diff --git a/dist/cjs/Alex2Node.js b/dist/cjs/Alex2Node.js
index f060321..330a918 100644
--- a/dist/cjs/Alex2Node.js
+++ b/dist/cjs/Alex2Node.js
@@ -1,4 +1,37 @@
 "use strict";
+var __createBinding = (this && this.__createBinding) || (Object.create ? (function(o, m, k, k2) {
+    if (k2 === undefined) k2 = k;
+    var desc = Object.getOwnPropertyDescriptor(m, k);
+    if (!desc || ("get" in desc ? !m.__esModule : desc.writable || desc.configurable)) {
+      desc = { enumerable: true, get: function() { return m[k]; } };
+    }
+    Object.defineProperty(o, k2, desc);
+}) : (function(o, m, k, k2) {
+    if (k2 === undefined) k2 = k;
+    o[k2] = m[k];
+}));
+var __setModuleDefault = (this && this.__setModuleDefault) || (Object.create ? (function(o, v) {
+    Object.defineProperty(o, "default", { enumerable: true, value: v });
+}) : function(o, v) {
+    o["default"] = v;
+});
+var __importStar = (this && this.__importStar) || (function () {
+    var ownKeys = function(o) {
+        ownKeys = Object.getOwnPropertyNames || function (o) {
+            var ar = [];
+            for (var k in o) if (Object.prototype.hasOwnProperty.call(o, k)) ar[ar.length] = k;
+            return ar;
+        };
+        return ownKeys(o);
+    };
+    return function (mod) {
+        if (mod && mod.__esModule) return mod;
+        var result = {};
+        if (mod != null) for (var k = ownKeys(mod), i = 0; i < k.length; i++) if (k[i] !== "default") __createBinding(result, mod, k[i]);
+        __setModuleDefault(result, mod);
+        return result;
+    };
+})();
 var __importDefault = (this && this.__importDefault) || function (mod) {
     return (mod && mod.__esModule) ? mod : { "default": mod };
 };
@@ -11,6 +44,8 @@ const validate_js_1 = require("./device/validate.js");
 const events_1 = require("events");
 const enums_js_1 = require("./compat/enums.js");
 const types_js_1 = require("./registry/types.js");
+const topics = __importStar(require("./topics.js"));
+const transport_js_1 = require("./transport.js");
 exports.DEFAULT_HOST = "mqtt://Alex2MQTT.stormysdream.club:1883";
 // What addDevice() copies from the definition to the device
 const DESCRIBED = [
@@ -39,6 +74,8 @@ class Alex2MQTT extends events_1.EventEmitter {
         this.rootTopic = rootTopic;
         this.debugLogging = debugLogging;
         this.client = null;
+        // One for the life of the bridge: the devices keep it over disconnect() and connect()
+        this.publisher = new transport_js_1.MqttPublisher(() => this.client);
         this.devices = [];
         // The lines of check() that were logged. Discovery comes every few minutes: a line is logged once.
         this.logged = new Set();
@@ -76,8 +113,6 @@ class Alex2MQTT extends events_1.EventEmitter {
             ...(this.options.mqtt || {}),
         };
         this.client = mqtt_1.default.connect(this.MqttHost, options);
-        for (const d of this.devices)
-            d.setMqttClient(this.client); // after a disconnect(): the devices publish through the new client
         this.client.on("connect", () => {
             this.connected = true;
             this.log("Connected to MQTT broker");
@@ -100,12 +135,12 @@ class Alex2MQTT extends events_1.EventEmitter {
                 this.log("Discovery request received, getting device json...");
                 const deviceArray = this.describeDevices();
                 this.lastDiscoveryAt = new Date().toISOString();
-                this.client.publish(topic + "_r", JSON.stringify(deviceArray), (err) => {
-                    if (err) {
-                        this.fail(err);
+                void this.publisher.publish(topics.discoverReply(this.rootTopic), deviceArray).then((result) => {
+                    if (!result.ok) {
+                        this.fail(result.error);
                         return;
                     }
-                    this.log(`Discovery payloads published to ${topic + "_r"}`, deviceArray);
+                    this.log(`Discovery payloads published to ${result.topic}`, deviceArray);
                     this.emit("discover", deviceArray.length);
                 });
             }
@@ -179,15 +214,13 @@ class Alex2MQTT extends events_1.EventEmitter {
      *
      * Throws a DeclarationError when Alexa would reject the endpoint (an endpointId with a slash, a name with
      * punctuation) or when the endpointId is registered already. Discovery lists Alexa.EndpointHealth for the device
-     * unless endpointHealth is false.
+     * unless endpointHealth is false. A device can be declared before connect(): what it sends before the bridge has
+     * a connection is not published, and the "error" event says so.
      */
     addDevice(definition) {
-        if (!this.client) {
-            throw new Error("Must call connect before creating devices");
-        }
         const { endpointId, name, categories, endpointHealth, ...described } = definition;
         // Without categories the device would take LIGHT, the default of registerDevice: here it is a mistake
-        const device = new Device_js_1.default(this.client, this.rootTopic, name, endpointId, (categories ?? []));
+        const device = new Device_js_1.default(null, this.rootTopic, name, endpointId, (categories ?? []));
         for (const [field, value] of Object.entries(described)) {
             if (!DESCRIBED.includes(field))
                 throw new types_js_1.DeclarationError({ endpointId }, `${field} is not a field of an endpoint`);
@@ -202,9 +235,6 @@ class Alex2MQTT extends events_1.EventEmitter {
         return device;
     }
     registerDevice(name, endpointId, displayCategory) {
-        if (!this.client) {
-            throw new Error("Must call connect before creating devices");
-        }
         const existing = this.devices.find((d) => d.endpointId === endpointId);
         if (existing) { // 1.5.2: endpointIds are unique per root topic; 1.5.1 added a second device that never got a directive
             const warning = `warning: registerDevice("${endpointId}") is already registered as "${existing.name}", returning that device`;
@@ -216,7 +246,7 @@ class Alex2MQTT extends events_1.EventEmitter {
         }
         this.log(`Creating new device with endpoint: ${endpointId}`);
         const normalizedCategory = Array.isArray(displayCategory) ? displayCategory : [displayCategory || enums_js_1.DisplayCategory.LIGHT];
-        const device = new Device_js_1.default(this.client, this.rootTopic, name, endpointId, normalizedCategory);
+        const device = new Device_js_1.default(null, this.rootTopic, name, endpointId, normalizedCategory);
         this.register(device, false);
         return device;
     }
@@ -224,6 +254,7 @@ class Alex2MQTT extends events_1.EventEmitter {
         device.alexaInterface = this.options.alexaInterface !== false;
         device.endpointHealth = endpointHealth;
         device.onPublishError = (err) => this.fail(err); // a failed publish is an "error" event (when listened to), never a rejected send()
+        device.publisher = this.publisher;
         this.devices.push(device);
     }
     /** Forget a device (its listeners with it). Returns false when there was none. */
@@ -231,16 +262,21 @@ class Alex2MQTT extends events_1.EventEmitter {
         const i = this.devices.findIndex((d) => d.endpointId === endpointId);
         if (i === -1)
             return false;
-        this.devices[i].removeAllListeners();
+        this.release(this.devices[i]);
         this.devices.splice(i, 1);
         return true;
     }
     /** Forget every device. */
     clearDevices() {
         for (const d of this.devices)
-            d.removeAllListeners();
+            this.release(d);
         this.devices = [];
     }
+    // A device the bridge forgot hears no directive and publishes nothing
+    release(device) {
+        device.removeAllListeners();
+        device.publisher = null;
+    }
     getDevices() {
         return this.devices.slice();
     }
diff --git a/dist/cjs/compat/AlexaErrorResponse.js b/dist/cjs/compat/AlexaErrorResponse.js
index 25a5d8e..4fb9359 100644
--- a/dist/cjs/compat/AlexaErrorResponse.js
+++ b/dist/cjs/compat/AlexaErrorResponse.js
@@ -1,16 +1,51 @@
 "use strict";
+var __createBinding = (this && this.__createBinding) || (Object.create ? (function(o, m, k, k2) {
+    if (k2 === undefined) k2 = k;
+    var desc = Object.getOwnPropertyDescriptor(m, k);
+    if (!desc || ("get" in desc ? !m.__esModule : desc.writable || desc.configurable)) {
+      desc = { enumerable: true, get: function() { return m[k]; } };
+    }
+    Object.defineProperty(o, k2, desc);
+}) : (function(o, m, k, k2) {
+    if (k2 === undefined) k2 = k;
+    o[k2] = m[k];
+}));
+var __setModuleDefault = (this && this.__setModuleDefault) || (Object.create ? (function(o, v) {
+    Object.defineProperty(o, "default", { enumerable: true, value: v });
+}) : function(o, v) {
+    o["default"] = v;
+});
+var __importStar = (this && this.__importStar) || (function () {
+    var ownKeys = function(o) {
+        ownKeys = Object.getOwnPropertyNames || function (o) {
+            var ar = [];
+            for (var k in o) if (Object.prototype.hasOwnProperty.call(o, k)) ar[ar.length] = k;
+            return ar;
+        };
+        return ownKeys(o);
+    };
+    return function (mod) {
+        if (mod && mod.__esModule) return mod;
+        var result = {};
+        if (mod != null) for (var k = ownKeys(mod), i = 0; i < k.length; i++) if (k[i] !== "default") __createBinding(result, mod, k[i]);
+        __setModuleDefault(result, mod);
+        return result;
+    };
+})();
 Object.defineProperty(exports, "__esModule", { value: true });
 exports.AlexaErrorResponse = void 0;
 const crypto_1 = require("crypto");
 const build_js_1 = require("../messages/build.js");
 const errors_js_1 = require("../messages/errors.js");
+const topics = __importStar(require("../topics.js"));
+const transport_js_1 = require("../transport.js");
 /** An ErrorResponse as 1.x builds it: device.getErrorMessage(token), setErrorMessage(), send(). */
 class AlexaErrorResponse {
-    constructor(correlationToken, rootTopic, endpointId, mqttClient) {
+    constructor(correlationToken, rootTopic, endpointId, publisher) {
         this.correlationToken = correlationToken;
         this.rootTopic = rootTopic;
         this.endpointId = endpointId;
-        this.mqttClient = mqttClient;
+        this.publisher = publisher;
         // Sent when setErrorMessage() was not called: 1.x published an empty payload, which is no ErrorResponse to Alexa
         this.error = errors_js_1.AlexaErrors.of("INTERNAL_ERROR", "the device answered with an error and did not say which");
         // One id for the message, however often toJSON() is called
@@ -39,16 +74,8 @@ class AlexaErrorResponse {
     }
     /** Resolves with the topic published to, or "" when the publish failed. Never rejects. */
     send(sendAsync = false) {
-        const topic = `${this.rootTopic}/${this.endpointId}/${sendAsync ? "deferredResponse" : "alexaResponce"}`; // "alexaResponce" is how Alex2MQTT and Alex2ESP spell the topic
-        return new Promise((resolve) => {
-            this.mqttClient.publish(topic, JSON.stringify(this.toJSON()), (err) => {
-                if (!err)
-                    return resolve(topic);
-                if (this.onPublishError)
-                    this.onPublishError(err); // -> the bridge's "error" event (when somebody listens)
-                resolve(""); // 1.5.1 rejected here, and an un-caught send() then killed the host on any broker hiccup
-            });
-        });
+        const answer = sendAsync ? topics.deferred : topics.response;
+        return (0, transport_js_1.send)(this.publisher, answer(this.rootTopic, this.endpointId), () => this.toJSON(), this.onPublishError);
     }
 }
 exports.AlexaErrorResponse = AlexaErrorResponse;
diff --git a/dist/cjs/compat/AlexaStatusMessage.js b/dist/cjs/compat/AlexaStatusMessage.js
index e31382a..00929fa 100644
--- a/dist/cjs/compat/AlexaStatusMessage.js
+++ b/dist/cjs/compat/AlexaStatusMessage.js
@@ -1,9 +1,44 @@
 "use strict";
+var __createBinding = (this && this.__createBinding) || (Object.create ? (function(o, m, k, k2) {
+    if (k2 === undefined) k2 = k;
+    var desc = Object.getOwnPropertyDescriptor(m, k);
+    if (!desc || ("get" in desc ? !m.__esModule : desc.writable || desc.configurable)) {
+      desc = { enumerable: true, get: function() { return m[k]; } };
+    }
+    Object.defineProperty(o, k2, desc);
+}) : (function(o, m, k, k2) {
+    if (k2 === undefined) k2 = k;
+    o[k2] = m[k];
+}));
+var __setModuleDefault = (this && this.__setModuleDefault) || (Object.create ? (function(o, v) {
+    Object.defineProperty(o, "default", { enumerable: true, value: v });
+}) : function(o, v) {
+    o["default"] = v;
+});
+var __importStar = (this && this.__importStar) || (function () {
+    var ownKeys = function(o) {
+        ownKeys = Object.getOwnPropertyNames || function (o) {
+            var ar = [];
+            for (var k in o) if (Object.prototype.hasOwnProperty.call(o, k)) ar[ar.length] = k;
+            return ar;
+        };
+        return ownKeys(o);
+    };
+    return function (mod) {
+        if (mod && mod.__esModule) return mod;
+        var result = {};
+        if (mod != null) for (var k = ownKeys(mod), i = 0; i < k.length; i++) if (k[i] !== "default") __createBinding(result, mod, k[i]);
+        __setModuleDefault(result, mod);
+        return result;
+    };
+})();
 Object.defineProperty(exports, "__esModule", { value: true });
 exports.AlexaStatusMessage = void 0;
 const crypto_1 = require("crypto");
 const build_js_1 = require("../messages/build.js");
 const StateBuilder_js_1 = require("../messages/StateBuilder.js");
+const topics = __importStar(require("../topics.js"));
+const transport_js_1 = require("../transport.js");
 const enums_js_1 = require("./enums.js");
 // The 1.x helpers report every temperature in Celsius, whatever scale the device works in
 function celsius(scale, value) {
@@ -14,11 +49,11 @@ function celsius(scale, value) {
  * device.getChangeReport(), the add...Prop() calls, send(). The values are not checked.
  */
 class AlexaStatusMessage {
-    constructor(correlationToken, rootTopic, endpointId, mqttClient, isResponse = false, isDeferred = false, changeCause = null) {
+    constructor(correlationToken, rootTopic, endpointId, publisher, isResponse = false, isDeferred = false, changeCause = null) {
         this.correlationToken = correlationToken;
         this.rootTopic = rootTopic;
         this.endpointId = endpointId;
-        this.mqttClient = mqttClient;
+        this.publisher = publisher;
         this.isResponse = isResponse;
         this.isDeferred = isDeferred;
         this.changeCause = changeCause;
@@ -109,24 +144,9 @@ class AlexaStatusMessage {
      * to). Never rejects (1.5.1 did, so an un-caught send() could kill the host).
      */
     send(sendAsync = false) {
-        const topic = this.changeCause
-            ? `${this.rootTopic}/changeReport`
-            : `${this.rootTopic}/${this.endpointId}/${sendAsync ? "deferredResponse" : "alexaResponce"}`; // "alexaResponce" is how Alex2MQTT and Alex2ESP spell the topic
-        return new Promise((resolve) => {
-            const failed = (err) => {
-                if (this.onPublishError)
-                    this.onPublishError(err); // -> the bridge's "error" event (when somebody listens)
-                resolve(""); // 1.5.1 rejected here, and an un-caught send() then killed the host on any broker hiccup
-            };
-            let payload;
-            try {
-                payload = JSON.stringify(this.toJSON());
-            }
-            catch (err) {
-                return failed(err);
-            }
-            this.mqttClient.publish(topic, payload, (err) => (err ? failed(err) : resolve(topic)));
-        });
+        const answer = sendAsync ? topics.deferred : topics.response;
+        const topic = this.changeCause ? topics.changeReport(this.rootTopic) : answer(this.rootTopic, this.endpointId);
+        return (0, transport_js_1.send)(this.publisher, topic, () => this.toJSON(), this.onPublishError);
     }
 }
 exports.AlexaStatusMessage = AlexaStatusMessage;
diff --git a/dist/cjs/device/Device.js b/dist/cjs/device/Device.js
index dacfd63..4f5485c 100644
--- a/dist/cjs/device/Device.js
+++ b/dist/cjs/device/Device.js
@@ -1,4 +1,37 @@
 "use strict";
+var __createBinding = (this && this.__createBinding) || (Object.create ? (function(o, m, k, k2) {
+    if (k2 === undefined) k2 = k;
+    var desc = Object.getOwnPropertyDescriptor(m, k);
+    if (!desc || ("get" in desc ? !m.__esModule : desc.writable || desc.configurable)) {
+      desc = { enumerable: true, get: function() { return m[k]; } };
+    }
+    Object.defineProperty(o, k2, desc);
+}) : (function(o, m, k, k2) {
+    if (k2 === undefined) k2 = k;
+    o[k2] = m[k];
+}));
+var __setModuleDefault = (this && this.__setModuleDefault) || (Object.create ? (function(o, v) {
+    Object.defineProperty(o, "default", { enumerable: true, value: v });
+}) : function(o, v) {
+    o["default"] = v;
+});
+var __importStar = (this && this.__importStar) || (function () {
+    var ownKeys = function(o) {
+        ownKeys = Object.getOwnPropertyNames || function (o) {
+            var ar = [];
+            for (var k in o) if (Object.prototype.hasOwnProperty.call(o, k)) ar[ar.length] = k;
+            return ar;
+        };
+        return ownKeys(o);
+    };
+    return function (mod) {
+        if (mod && mod.__esModule) return mod;
+        var result = {};
+        if (mod != null) for (var k = ownKeys(mod), i = 0; i < k.length; i++) if (k[i] !== "default") __createBinding(result, mod, k[i]);
+        __setModuleDefault(result, mod);
+        return result;
+    };
+})();
 Object.defineProperty(exports, "__esModule", { value: true });
 const events_1 = require("events");
 const AlexaErrorResponse_js_1 = require("../compat/AlexaErrorResponse.js");
@@ -10,12 +43,14 @@ const Alexa_js_1 = require("../registry/interfaces/Alexa.js");
 const EndpointHealth_js_1 = require("../registry/interfaces/EndpointHealth.js");
 const schema_js_1 = require("../registry/schema.js");
 const types_js_1 = require("../registry/types.js");
+const topics = __importStar(require("../topics.js"));
+const transport_js_1 = require("../transport.js");
 const Capability_js_1 = require("./Capability.js");
 const validate_js_1 = require("./validate.js");
 class Device extends events_1.EventEmitter {
-    constructor(mqttClient, rootTopic, name, endpointId, displayCategory, description = "Alexa to Node.js bridge", manufacturerName = "Alex2Node", manufacturer = "Alex2Node", model = "Alex2Node_v1.0.0") {
+    /** client is ignored: in 1.x it was the broker client, and a device could only be built after connect(). */
+    constructor(client, rootTopic, name, endpointId, displayCategory, description = "Alexa to Node.js bridge", manufacturerName = "Alex2Node", manufacturer = "Alex2Node", model = "Alex2Node_v1.0.0") {
         super();
-        this.mqttClient = mqttClient;
         this.rootTopic = rootTopic;
         this.name = name;
         this.endpointId = endpointId;
@@ -39,10 +74,12 @@ class Device extends events_1.EventEmitter {
          */
         this.endpointHealth = false;
         this.capabilities = [];
-    }
-    /** Internal (1.5.2): Alex2MQTT.connect() re-binds every registered device to its new broker client after a disconnect(). */
-    setMqttClient(client) {
-        this.mqttClient = client;
+        /**
+         * What the device and the messages it builds publish through. The bridge sets it when the device is registered
+         * and clears it when the device is unregistered; a MemoryPublisher here tests a device without a broker. While it
+         * is null every send() resolves "" and reports why.
+         */
+        this.publisher = null;
     }
     getName() {
         return this.name;
@@ -66,12 +103,12 @@ class Device extends events_1.EventEmitter {
         return this.description;
     }
     getErrorMessage(correlationToken) {
-        const msg = new AlexaErrorResponse_js_1.AlexaErrorResponse(correlationToken, this.rootTopic, this.endpointId, this.mqttClient);
+        const msg = new AlexaErrorResponse_js_1.AlexaErrorResponse(correlationToken, this.rootTopic, this.endpointId, this.publisher);
         msg.onPublishError = this.onPublishError;
         return msg;
     }
     getStatusMessage(correlationToken, isResponse = false, isDeferred = false) {
-        const msg = new AlexaStatusMessage_js_1.AlexaStatusMessage(correlationToken, this.rootTopic, this.endpointId, this.mqttClient, isResponse, isDeferred);
+        const msg = new AlexaStatusMessage_js_1.AlexaStatusMessage(correlationToken, this.rootTopic, this.endpointId, this.publisher, isResponse, isDeferred);
         msg.onPublishError = this.onPublishError;
         return msg;
     }
@@ -82,7 +119,7 @@ class Device extends events_1.EventEmitter {
      * Without a changed property send() publishes nothing and resolves with "": Alex2MQTT would drop the report.
      */
     getChangeReport(cause = "PHYSICAL_INTERACTION") {
-        const msg = new AlexaStatusMessage_js_1.AlexaStatusMessage("", this.rootTopic, this.endpointId, this.mqttClient, false, false, cause);
+        const msg = new AlexaStatusMessage_js_1.AlexaStatusMessage("", this.rootTopic, this.endpointId, this.publisher, false, false, cause);
         msg.onPublishError = this.onPublishError;
         return msg;
     }
@@ -91,17 +128,9 @@ class Device extends events_1.EventEmitter {
      * (1.5.1). Resolves with the topic published to, or "" when the publish failed (never rejects, 1.5.2).
      */
     sendSceneResponse(correlationToken, activated, cause = "VOICE_INTERACTION", sendAsync = false) {
-        const payload = (0, build_js_1.sceneEvent)({ endpointId: this.endpointId, correlationToken, activated, cause });
-        const topic = `${this.rootTopic}/${this.endpointId}/${sendAsync ? "deferredResponse" : "alexaResponce"}`;
-        return new Promise((resolve) => {
-            this.mqttClient.publish(topic, JSON.stringify(payload), (err) => {
-                if (!err)
-                    return resolve(topic);
-                if (this.onPublishError)
-                    this.onPublishError(err); // -> the bridge's "error" event (when somebody listens)
-                resolve(""); // 1.5.1 rejected here, and an un-caught send() then killed the host on any broker hiccup
-            });
-        });
+        const answer = sendAsync ? topics.deferred : topics.response;
+        const build = () => (0, build_js_1.sceneEvent)({ endpointId: this.endpointId, correlationToken, activated, cause });
+        return (0, transport_js_1.send)(this.publisher, answer(this.rootTopic, this.endpointId), build, this.onPublishError);
     }
     /** The capabilities the device declared, in the order it declared them. */
     getCapabilities() {
diff --git a/dist/cjs/index.js b/dist/cjs/index.js
index 774c919..c3fcd76 100644
--- a/dist/cjs/index.js
+++ b/dist/cjs/index.js
@@ -36,7 +36,7 @@ var __importDefault = (this && this.__importDefault) || function (mod) {
     return (mod && mod.__esModule) ? mod : { "default": mod };
 };
 Object.defineProperty(exports, "__esModule", { value: true });
-exports.AlexaErrorResponse = exports.AlexaStatusMessage = exports.ThermostatMode = exports.TemperatureSensorScale = exports.PowerState = exports.DisplayCategory = exports.AlexaInterfaceType = exports.AlexaErrorType = exports.AlexaActions = exports.ActionMapping = exports.AlexaInterface = exports.property = exports.StateBuilder = exports.MessageError = exports.AlexaErrors = exports.AlexaError = exports.messages = exports.DisplayCategories = exports.States = exports.Actions = exports.Units = exports.Assets = exports.SemanticsBuilder = exports.semantics = exports.text = exports.asset = exports.EndpointHealth = exports.PowerController = exports.ToggleController = exports.TemperatureSensor = exports.RangeController = exports.ModeController = exports.BrightnessController = exports.Alexa = exports.SchemaError = exports.DeclarationError = exports.registry = exports.Capability = exports.Device = exports.DEFAULT_HOST = exports.Alex2MQTT = void 0;
+exports.AlexaErrorResponse = exports.AlexaStatusMessage = exports.ThermostatMode = exports.TemperatureSensorScale = exports.PowerState = exports.DisplayCategory = exports.AlexaInterfaceType = exports.AlexaErrorType = exports.AlexaActions = exports.ActionMapping = exports.AlexaInterface = exports.MemoryPublisher = exports.topics = exports.property = exports.StateBuilder = exports.MessageError = exports.AlexaErrors = exports.AlexaError = exports.messages = exports.DisplayCategories = exports.States = exports.Actions = exports.Units = exports.Assets = exports.SemanticsBuilder = exports.semantics = exports.text = exports.asset = exports.EndpointHealth = exports.PowerController = exports.ToggleController = exports.TemperatureSensor = exports.RangeController = exports.ModeController = exports.BrightnessController = exports.Alexa = exports.SchemaError = exports.DeclarationError = exports.registry = exports.Capability = exports.Device = exports.DEFAULT_HOST = exports.Alex2MQTT = void 0;
 // Relative specifiers carry ".js": Node's ES module loader resolves no extension, and TypeScript maps it back to the .ts.
 var Alex2Node_js_1 = require("./Alex2Node.js");
 Object.defineProperty(exports, "Alex2MQTT", { enumerable: true, get: function () { return __importDefault(Alex2Node_js_1).default; } });
@@ -80,6 +80,10 @@ Object.defineProperty(exports, "AlexaErrors", { enumerable: true, get: function
 Object.defineProperty(exports, "MessageError", { enumerable: true, get: function () { return index_js_5.MessageError; } });
 Object.defineProperty(exports, "StateBuilder", { enumerable: true, get: function () { return index_js_5.StateBuilder; } });
 Object.defineProperty(exports, "property", { enumerable: true, get: function () { return index_js_5.property; } });
+// Publishing: the topics of the Alex2MQTT contract, and a publisher that needs no broker for tests
+exports.topics = __importStar(require("./topics.js"));
+var transport_js_1 = require("./transport.js");
+Object.defineProperty(exports, "MemoryPublisher", { enumerable: true, get: function () { return transport_js_1.MemoryPublisher; } });
 // 1.x
 var AlexaInterface_js_1 = require("./compat/AlexaInterface.js");
 Object.defineProperty(exports, "AlexaInterface", { enumerable: true, get: function () { return AlexaInterface_js_1.AlexaInterface; } });
diff --git a/dist/cjs/topics.js b/dist/cjs/topics.js
new file mode 100644
index 0000000..45f2d53
--- /dev/null
+++ b/dist/cjs/topics.js
@@ -0,0 +1,17 @@
+"use strict";
+// The topics of the Alex2MQTT contract, named once. The backend and Alex2ESP use the same names, so none of them
+// can change here alone.
+Object.defineProperty(exports, "__esModule", { value: true });
+exports.changeReport = exports.deferred = exports.response = exports.discoverReply = void 0;
+/** Where the bridge answers a discovery request with its endpoints. */
+const discoverReply = (root) => `${root}/discover_r`;
+exports.discoverReply = discoverReply;
+/** Where the answer to a directive goes. "alexaResponce" is how the backend and Alex2ESP spell it. */
+const response = (root, endpointId) => `${root}/${endpointId}/alexaResponce`;
+exports.response = response;
+/** Where the answer goes once a DeferredResponse was sent for the directive. */
+const deferred = (root, endpointId) => `${root}/${endpointId}/deferredResponse`;
+exports.deferred = deferred;
+/** Where every ChangeReport of the root goes: the backend adds the user's token and posts it to Alexa. */
+const changeReport = (root) => `${root}/changeReport`;
+exports.changeReport = changeReport;
diff --git a/dist/cjs/transport.js b/dist/cjs/transport.js
new file mode 100644
index 0000000..0d97477
--- /dev/null
+++ b/dist/cjs/transport.js
@@ -0,0 +1,83 @@
+"use strict";
+Object.defineProperty(exports, "__esModule", { value: true });
+exports.MemoryPublisher = exports.MqttPublisher = void 0;
+exports.send = send;
+const asError = (err) => (err instanceof Error ? err : new Error(String(err)));
+/**
+ * Publishes to the broker through the client the bridge has at the time: a new one after disconnect() and connect(),
+ * none before connect() and after disconnect(). Without a client the publish is refused. With a client that lost
+ * its connection mqtt.js keeps the message and sends it after the reconnect, and the publish resolves then.
+ */
+class MqttPublisher {
+    constructor(client) {
+        this.client = client;
+    }
+    publish(topic, message) {
+        const client = this.client();
+        return new Promise((resolve) => {
+            const failed = (err) => resolve({ ok: false, topic, error: asError(err) });
+            if (!client) {
+                failed(new Error(`nothing was published to ${topic}: the bridge is not connected, call connect() first`));
+                return;
+            }
+            try {
+                client.publish(topic, JSON.stringify(message), (err) => (err ? failed(err) : resolve({ ok: true, topic })));
+            }
+            catch (err) {
+                failed(err);
+            }
+        });
+    }
+}
+exports.MqttPublisher = MqttPublisher;
+/**
+ * Keeps what it is asked to publish, for tests and dry runs without a broker:
+ *
+ *   const sent = new MemoryPublisher();
+ *   device.publisher = sent;
+ *   await device.getStatusMessage(token, true).addPowerControllerProp(PowerController.ON).send();
+ *   sent.published[0]   // { topic: "<root>/<endpointId>/alexaResponce", message: { event, context } }
+ */
+class MemoryPublisher {
+    constructor() {
+        /** Oldest first. The message is what a subscriber gets after JSON.parse. */
+        this.published = [];
+        /** Set it and every publish fails with this error, as a publish to a broker that is gone does. */
+        this.failWith = null;
+    }
+    publish(topic, message) {
+        if (this.failWith)
+            return Promise.resolve({ ok: false, topic, error: this.failWith });
+        try {
+            this.published.push({ topic, message: JSON.parse(JSON.stringify(message)) });
+        }
+        catch (err) {
+            return Promise.resolve({ ok: false, topic, error: asError(err) });
+        }
+        return Promise.resolve({ ok: true, topic });
+    }
+}
+exports.MemoryPublisher = MemoryPublisher;
+/**
+ * send() as 1.x promises it: resolves with the topic, or with "" when nothing was published, and never rejects
+ * (1.5.1 rejected, and a send() nobody caught killed the host on any broker hiccup). What went wrong goes to report:
+ * the message cannot be built, the device is on no bridge, or the publish failed.
+ */
+async function send(publisher, topic, build, report) {
+    let result;
+    try {
+        const message = build();
+        if (!publisher) {
+            throw new Error(`nothing was published to ${topic}: the device is on no bridge, register it with addDevice() or registerDevice()`);
+        }
+        result = await publisher.publish(topic, message);
+    }
+    catch (err) {
+        result = { ok: false, topic, error: asError(err) };
+    }
+    if (result.ok)
+        return topic;
+    if (report)
+        report(result.error);
+    return "";
+}
diff --git a/dist/esm/Alex2Node.d.ts b/dist/esm/Alex2Node.d.ts
index 983e964..e7d45dc 100644
--- a/dist/esm/Alex2Node.d.ts
+++ b/dist/esm/Alex2Node.d.ts
@@ -38,6 +38,7 @@ declare class Alex2MQTT extends EventEmitter {
     private rootTopic;
     private debugLogging;
     private client;
+    private readonly publisher;
     private devices;
     private MqttHost;
     private options;
@@ -62,7 +63,8 @@ declare class Alex2MQTT extends EventEmitter {
      *
      * Throws a DeclarationError when Alexa would reject the endpoint (an endpointId with a slash, a name with
      * punctuation) or when the endpointId is registered already. Discovery lists Alexa.EndpointHealth for the device
-     * unless endpointHealth is false.
+     * unless endpointHealth is false. A device can be declared before connect(): what it sends before the bridge has
+     * a connection is not published, and the "error" event says so.
      */
     addDevice(definition: EndpointDefinition): Device;
     registerDevice(name: string, endpointId: string, displayCategory?: DisplayCategory | DisplayCategory[] | null): Device;
@@ -71,6 +73,7 @@ declare class Alex2MQTT extends EventEmitter {
     unregisterDevice(endpointId: string): boolean;
     /** Forget every device. */
     clearDevices(): void;
+    private release;
     getDevices(): Device[];
     getDevice(endpointId: string): Device | undefined;
     getRootTopic(): string;
diff --git a/dist/esm/Alex2Node.js b/dist/esm/Alex2Node.js
index 6838e74..0be84a6 100644
--- a/dist/esm/Alex2Node.js
+++ b/dist/esm/Alex2Node.js
@@ -5,6 +5,8 @@ import { checkEndpoint } from "./device/validate.js";
 import { EventEmitter } from "events";
 import { DisplayCategory } from "./compat/enums.js";
 import { DeclarationError } from "./registry/types.js";
+import * as topics from "./topics.js";
+import { MqttPublisher } from "./transport.js";
 export const DEFAULT_HOST = "mqtt://Alex2MQTT.stormysdream.club:1883";
 // What addDevice() copies from the definition to the device
 const DESCRIBED = [
@@ -33,6 +35,8 @@ class Alex2MQTT extends EventEmitter {
         this.rootTopic = rootTopic;
         this.debugLogging = debugLogging;
         this.client = null;
+        // One for the life of the bridge: the devices keep it over disconnect() and connect()
+        this.publisher = new MqttPublisher(() => this.client);
         this.devices = [];
         // The lines of check() that were logged. Discovery comes every few minutes: a line is logged once.
         this.logged = new Set();
@@ -70,8 +74,6 @@ class Alex2MQTT extends EventEmitter {
             ...(this.options.mqtt || {}),
         };
         this.client = mqtt.connect(this.MqttHost, options);
-        for (const d of this.devices)
-            d.setMqttClient(this.client); // after a disconnect(): the devices publish through the new client
         this.client.on("connect", () => {
             this.connected = true;
             this.log("Connected to MQTT broker");
@@ -94,12 +96,12 @@ class Alex2MQTT extends EventEmitter {
                 this.log("Discovery request received, getting device json...");
                 const deviceArray = this.describeDevices();
                 this.lastDiscoveryAt = new Date().toISOString();
-                this.client.publish(topic + "_r", JSON.stringify(deviceArray), (err) => {
-                    if (err) {
-                        this.fail(err);
+                void this.publisher.publish(topics.discoverReply(this.rootTopic), deviceArray).then((result) => {
+                    if (!result.ok) {
+                        this.fail(result.error);
                         return;
                     }
-                    this.log(`Discovery payloads published to ${topic + "_r"}`, deviceArray);
+                    this.log(`Discovery payloads published to ${result.topic}`, deviceArray);
                     this.emit("discover", deviceArray.length);
                 });
             }
@@ -173,15 +175,13 @@ class Alex2MQTT extends EventEmitter {
      *
      * Throws a DeclarationError when Alexa would reject the endpoint (an endpointId with a slash, a name with
      * punctuation) or when the endpointId is registered already. Discovery lists Alexa.EndpointHealth for the device
-     * unless endpointHealth is false.
+     * unless endpointHealth is false. A device can be declared before connect(): what it sends before the bridge has
+     * a connection is not published, and the "error" event says so.
      */
     addDevice(definition) {
-        if (!this.client) {
-            throw new Error("Must call connect before creating devices");
-        }
         const { endpointId, name, categories, endpointHealth, ...described } = definition;
         // Without categories the device would take LIGHT, the default of registerDevice: here it is a mistake
-        const device = new Device(this.client, this.rootTopic, name, endpointId, (categories ?? []));
+        const device = new Device(null, this.rootTopic, name, endpointId, (categories ?? []));
         for (const [field, value] of Object.entries(described)) {
             if (!DESCRIBED.includes(field))
                 throw new DeclarationError({ endpointId }, `${field} is not a field of an endpoint`);
@@ -196,9 +196,6 @@ class Alex2MQTT extends EventEmitter {
         return device;
     }
     registerDevice(name, endpointId, displayCategory) {
-        if (!this.client) {
-            throw new Error("Must call connect before creating devices");
-        }
         const existing = this.devices.find((d) => d.endpointId === endpointId);
         if (existing) { // 1.5.2: endpointIds are unique per root topic; 1.5.1 added a second device that never got a directive
             const warning = `warning: registerDevice("${endpointId}") is already registered as "${existing.name}", returning that device`;
@@ -210,7 +207,7 @@ class Alex2MQTT extends EventEmitter {
         }
         this.log(`Creating new device with endpoint: ${endpointId}`);
         const normalizedCategory = Array.isArray(displayCategory) ? displayCategory : [displayCategory || DisplayCategory.LIGHT];
-        const device = new Device(this.client, this.rootTopic, name, endpointId, normalizedCategory);
+        const device = new Device(null, this.rootTopic, name, endpointId, normalizedCategory);
         this.register(device, false);
         return device;
     }
@@ -218,6 +215,7 @@ class Alex2MQTT extends EventEmitter {
         device.alexaInterface = this.options.alexaInterface !== false;
         device.endpointHealth = endpointHealth;
         device.onPublishError = (err) => this.fail(err); // a failed publish is an "error" event (when listened to), never a rejected send()
+        device.publisher = this.publisher;
         this.devices.push(device);
     }
     /** Forget a device (its listeners with it). Returns false when there was none. */
@@ -225,16 +223,21 @@ class Alex2MQTT extends EventEmitter {
         const i = this.devices.findIndex((d) => d.endpointId === endpointId);
         if (i === -1)
             return false;
-        this.devices[i].removeAllListeners();
+        this.release(this.devices[i]);
         this.devices.splice(i, 1);
         return true;
     }
     /** Forget every device. */
     clearDevices() {
         for (const d of this.devices)
-            d.removeAllListeners();
+            this.release(d);
         this.devices = [];
     }
+    // A device the bridge forgot hears no directive and publishes nothing
+    release(device) {
+        device.removeAllListeners();
+        device.publisher = null;
+    }
     getDevices() {
         return this.devices.slice();
     }
diff --git a/dist/esm/compat/AlexaErrorResponse.d.ts b/dist/esm/compat/AlexaErrorResponse.d.ts
index 389b6cc..696f1ea 100644
--- a/dist/esm/compat/AlexaErrorResponse.d.ts
+++ b/dist/esm/compat/AlexaErrorResponse.d.ts
@@ -1,17 +1,17 @@
-import type { MqttClient } from "mqtt";
 import type { ErrorResponseMessage } from "../messages/types.js";
+import type { Publisher } from "../transport.js";
 /** An ErrorResponse as 1.x builds it: device.getErrorMessage(token), setErrorMessage(), send(). */
 export declare class AlexaErrorResponse {
     private readonly correlationToken;
     private readonly rootTopic;
     private readonly endpointId;
-    private readonly mqttClient;
+    private readonly publisher;
     private error;
     private namespace?;
     private readonly messageId;
     /** Where a failed publish is reported (set by the Device that built this message, 1.5.2): send() never rejects. */
     onPublishError?: (err: Error) => void;
-    constructor(correlationToken: string, rootTopic: string, endpointId: string, mqttClient: MqttClient);
+    constructor(correlationToken: string, rootTopic: string, endpointId: string, publisher: Publisher | null);
     /**
      * The error to answer with. otherParams are the fields the type adds to the payload (validRange). The header
      * carries the namespace the type is documented under, Alexa.ThermostatController for THERMOSTAT_IS_OFF;
diff --git a/dist/esm/compat/AlexaErrorResponse.js b/dist/esm/compat/AlexaErrorResponse.js
index 84cb1eb..a91cfb5 100644
--- a/dist/esm/compat/AlexaErrorResponse.js
+++ b/dist/esm/compat/AlexaErrorResponse.js
@@ -1,13 +1,15 @@
 import { randomUUID } from "crypto";
 import { errorResponse } from "../messages/build.js";
 import { AlexaErrors } from "../messages/errors.js";
+import * as topics from "../topics.js";
+import { send } from "../transport.js";
 /** An ErrorResponse as 1.x builds it: device.getErrorMessage(token), setErrorMessage(), send(). */
 export class AlexaErrorResponse {
-    constructor(correlationToken, rootTopic, endpointId, mqttClient) {
+    constructor(correlationToken, rootTopic, endpointId, publisher) {
         this.correlationToken = correlationToken;
         this.rootTopic = rootTopic;
         this.endpointId = endpointId;
-        this.mqttClient = mqttClient;
+        this.publisher = publisher;
         // Sent when setErrorMessage() was not called: 1.x published an empty payload, which is no ErrorResponse to Alexa
         this.error = AlexaErrors.of("INTERNAL_ERROR", "the device answered with an error and did not say which");
         // One id for the message, however often toJSON() is called
@@ -36,15 +38,7 @@ export class AlexaErrorResponse {
     }
     /** Resolves with the topic published to, or "" when the publish failed. Never rejects. */
     send(sendAsync = false) {
-        const topic = `${this.rootTopic}/${this.endpointId}/${sendAsync ? "deferredResponse" : "alexaResponce"}`; // "alexaResponce" is how Alex2MQTT and Alex2ESP spell the topic
-        return new Promise((resolve) => {
-            this.mqttClient.publish(topic, JSON.stringify(this.toJSON()), (err) => {
-                if (!err)
-                    return resolve(topic);
-                if (this.onPublishError)
-                    this.onPublishError(err); // -> the bridge's "error" event (when somebody listens)
-                resolve(""); // 1.5.1 rejected here, and an un-caught send() then killed the host on any broker hiccup
-            });
-        });
+        const answer = sendAsync ? topics.deferred : topics.response;
+        return send(this.publisher, answer(this.rootTopic, this.endpointId), () => this.toJSON(), this.onPublishError);
     }
 }
diff --git a/dist/esm/compat/AlexaStatusMessage.d.ts b/dist/esm/compat/AlexaStatusMessage.d.ts
index f4dee17..2f9e51a 100644
--- a/dist/esm/compat/AlexaStatusMessage.d.ts
+++ b/dist/esm/compat/AlexaStatusMessage.d.ts
@@ -1,5 +1,5 @@
-import type { MqttClient } from "mqtt";
 import type { ChangeCause, Property } from "../messages/types.js";
+import type { Publisher } from "../transport.js";
 import { TemperatureSensorScale } from "./enums.js";
 import type { EndpointHealth, PowerController } from "./enums.js";
 /**
@@ -10,7 +10,7 @@ export declare class AlexaStatusMessage {
     private readonly correlationToken;
     private readonly rootTopic;
     private readonly endpointId;
-    private readonly mqttClient;
+    private readonly publisher;
     private readonly isResponse;
     private readonly isDeferred;
     private readonly changeCause;
@@ -19,7 +19,7 @@ export declare class AlexaStatusMessage {
     private estimatedDeferralInSeconds?;
     /** Where a failed publish is reported (set by the Device that built this message, 1.5.2): send() never rejects. */
     onPublishError?: (err: Error) => void;
-    constructor(correlationToken: string, rootTopic: string, endpointId: string, mqttClient: MqttClient, isResponse?: boolean, isDeferred?: boolean, changeCause?: ChangeCause | null);
+    constructor(correlationToken: string, rootTopic: string, endpointId: string, publisher: Publisher | null, isResponse?: boolean, isDeferred?: boolean, changeCause?: ChangeCause | null);
     private addProperty;
     /** ChangeReport: the add*Prop calls that follow describe what CHANGED (the default for a change report). */
     changed(): this;
diff --git a/dist/esm/compat/AlexaStatusMessage.js b/dist/esm/compat/AlexaStatusMessage.js
index 75e1f4c..e84e73a 100644
--- a/dist/esm/compat/AlexaStatusMessage.js
+++ b/dist/esm/compat/AlexaStatusMessage.js
@@ -1,6 +1,8 @@
 import { randomUUID } from "crypto";
 import { changeReport, deferredResponse, response } from "../messages/build.js";
 import { StateBuilder } from "../messages/StateBuilder.js";
+import * as topics from "../topics.js";
+import { send } from "../transport.js";
 import { AlexaInterfaceType, TemperatureSensorScale } from "./enums.js";
 // The 1.x helpers report every temperature in Celsius, whatever scale the device works in
 function celsius(scale, value) {
@@ -11,11 +13,11 @@ function celsius(scale, value) {
  * device.getChangeReport(), the add...Prop() calls, send(). The values are not checked.
  */
 export class AlexaStatusMessage {
-    constructor(correlationToken, rootTopic, endpointId, mqttClient, isResponse = false, isDeferred = false, changeCause = null) {
+    constructor(correlationToken, rootTopic, endpointId, publisher, isResponse = false, isDeferred = false, changeCause = null) {
         this.correlationToken = correlationToken;
         this.rootTopic = rootTopic;
         this.endpointId = endpointId;
-        this.mqttClient = mqttClient;
+        this.publisher = publisher;
         this.isResponse = isResponse;
         this.isDeferred = isDeferred;
         this.changeCause = changeCause;
@@ -106,23 +108,8 @@ export class AlexaStatusMessage {
      * to). Never rejects (1.5.1 did, so an un-caught send() could kill the host).
      */
     send(sendAsync = false) {
-        const topic = this.changeCause
-            ? `${this.rootTopic}/changeReport`
-            : `${this.rootTopic}/${this.endpointId}/${sendAsync ? "deferredResponse" : "alexaResponce"}`; // "alexaResponce" is how Alex2MQTT and Alex2ESP spell the topic
-        return new Promise((resolve) => {
-            const failed = (err) => {
-                if (this.onPublishError)
-                    this.onPublishError(err); // -> the bridge's "error" event (when somebody listens)
-                resolve(""); // 1.5.1 rejected here, and an un-caught send() then killed the host on any broker hiccup
-            };
-            let payload;
-            try {
-                payload = JSON.stringify(this.toJSON());
-            }
-            catch (err) {
-                return failed(err);
-            }
-            this.mqttClient.publish(topic, payload, (err) => (err ? failed(err) : resolve(topic)));
-        });
+        const answer = sendAsync ? topics.deferred : topics.response;
+        const topic = this.changeCause ? topics.changeReport(this.rootTopic) : answer(this.rootTopic, this.endpointId);
+        return send(this.publisher, topic, () => this.toJSON(), this.onPublishError);
     }
 }
diff --git a/dist/esm/device/Device.d.ts b/dist/esm/device/Device.d.ts
index f404968..5f0d570 100644
--- a/dist/esm/device/Device.d.ts
+++ b/dist/esm/device/Device.d.ts
@@ -1,5 +1,4 @@
 import { EventEmitter } from "events";
-import type { MqttClient } from "mqtt";
 import { AlexaErrorResponse } from "../compat/AlexaErrorResponse.js";
 import { AlexaInterface } from "../compat/AlexaInterface.js";
 import { AlexaStatusMessage } from "../compat/AlexaStatusMessage.js";
@@ -8,6 +7,7 @@ import type { AlexaInterfaceType } from "../compat/enums.js";
 import type { ChangeCause } from "../messages/types.js";
 import type { DisplayCategoryName } from "../registry/catalog.js";
 import type { Directives, InterfaceDescriptor, Properties } from "../registry/types.js";
+import type { Publisher } from "../transport.js";
 import { Capability } from "./Capability.js";
 import type { AnyCapability, CapabilityJson, Declaration } from "./Capability.js";
 import type { EndpointFields } from "./validate.js";
@@ -40,7 +40,6 @@ export interface EndpointJson extends EndpointFields {
 }
 type DeclarationArguments<O, I extends boolean> = {} extends Declaration<O, I> ? [options?: Declaration<O, I>] : [options: Declaration<O, I>];
 declare class Device extends EventEmitter {
-    private mqttClient;
     private rootTopic;
     name: string;
     endpointId: string;
@@ -67,9 +66,14 @@ declare class Device extends EventEmitter {
     private capabilities;
     /** Where a failed publish from this device or a message it built is reported; Alex2MQTT sets it (1.5.2). */
     onPublishError?: (err: Error) => void;
-    constructor(mqttClient: MqttClient, rootTopic: string, name: string, endpointId: string, displayCategory: Array<DisplayCategory> | null, description?: string, manufacturerName?: string, manufacturer?: string, model?: string);
-    /** Internal (1.5.2): Alex2MQTT.connect() re-binds every registered device to its new broker client after a disconnect(). */
-    setMqttClient(client: MqttClient): void;
+    /**
+     * What the device and the messages it builds publish through. The bridge sets it when the device is registered
+     * and clears it when the device is unregistered; a MemoryPublisher here tests a device without a broker. While it
+     * is null every send() resolves "" and reports why.
+     */
+    publisher: Publisher | null;
+    /** client is ignored: in 1.x it was the broker client, and a device could only be built after connect(). */
+    constructor(client: unknown, rootTopic: string, name: string, endpointId: string, displayCategory: Array<DisplayCategory> | null, description?: string, manufacturerName?: string, manufacturer?: string, model?: string);
     getName(): string;
     setName(name: string): void;
     getEndpointId(): string;
diff --git a/dist/esm/device/Device.js b/dist/esm/device/Device.js
index 87f334c..8137755 100644
--- a/dist/esm/device/Device.js
+++ b/dist/esm/device/Device.js
@@ -8,12 +8,14 @@ import { Alexa } from "../registry/interfaces/Alexa.js";
 import { EndpointHealth } from "../registry/interfaces/EndpointHealth.js";
 import { SchemaError } from "../registry/schema.js";
 import { DeclarationError } from "../registry/types.js";
+import * as topics from "../topics.js";
+import { send } from "../transport.js";
 import { Capability, commonOptions } from "./Capability.js";
 import { checkCapability, checkCapabilityCount, checkEndpoint } from "./validate.js";
 class Device extends EventEmitter {
-    constructor(mqttClient, rootTopic, name, endpointId, displayCategory, description = "Alexa to Node.js bridge", manufacturerName = "Alex2Node", manufacturer = "Alex2Node", model = "Alex2Node_v1.0.0") {
+    /** client is ignored: in 1.x it was the broker client, and a device could only be built after connect(). */
+    constructor(client, rootTopic, name, endpointId, displayCategory, description = "Alexa to Node.js bridge", manufacturerName = "Alex2Node", manufacturer = "Alex2Node", model = "Alex2Node_v1.0.0") {
         super();
-        this.mqttClient = mqttClient;
         this.rootTopic = rootTopic;
         this.name = name;
         this.endpointId = endpointId;
@@ -37,10 +39,12 @@ class Device extends EventEmitter {
          */
         this.endpointHealth = false;
         this.capabilities = [];
-    }
-    /** Internal (1.5.2): Alex2MQTT.connect() re-binds every registered device to its new broker client after a disconnect(). */
-    setMqttClient(client) {
-        this.mqttClient = client;
+        /**
+         * What the device and the messages it builds publish through. The bridge sets it when the device is registered
+         * and clears it when the device is unregistered; a MemoryPublisher here tests a device without a broker. While it
+         * is null every send() resolves "" and reports why.
+         */
+        this.publisher = null;
     }
     getName() {
         return this.name;
@@ -64,12 +68,12 @@ class Device extends EventEmitter {
         return this.description;
     }
     getErrorMessage(correlationToken) {
-        const msg = new AlexaErrorResponse(correlationToken, this.rootTopic, this.endpointId, this.mqttClient);
+        const msg = new AlexaErrorResponse(correlationToken, this.rootTopic, this.endpointId, this.publisher);
         msg.onPublishError = this.onPublishError;
         return msg;
     }
     getStatusMessage(correlationToken, isResponse = false, isDeferred = false) {
-        const msg = new AlexaStatusMessage(correlationToken, this.rootTopic, this.endpointId, this.mqttClient, isResponse, isDeferred);
+        const msg = new AlexaStatusMessage(correlationToken, this.rootTopic, this.endpointId, this.publisher, isResponse, isDeferred);
         msg.onPublishError = this.onPublishError;
         return msg;
     }
@@ -80,7 +84,7 @@ class Device extends EventEmitter {
      * Without a changed property send() publishes nothing and resolves with "": Alex2MQTT would drop the report.
      */
     getChangeReport(cause = "PHYSICAL_INTERACTION") {
-        const msg = new AlexaStatusMessage("", this.rootTopic, this.endpointId, this.mqttClient, false, false, cause);
+        const msg = new AlexaStatusMessage("", this.rootTopic, this.endpointId, this.publisher, false, false, cause);
         msg.onPublishError = this.onPublishError;
         return msg;
     }
@@ -89,17 +93,9 @@ class Device extends EventEmitter {
      * (1.5.1). Resolves with the topic published to, or "" when the publish failed (never rejects, 1.5.2).
      */
     sendSceneResponse(correlationToken, activated, cause = "VOICE_INTERACTION", sendAsync = false) {
-        const payload = sceneEvent({ endpointId: this.endpointId, correlationToken, activated, cause });
-        const topic = `${this.rootTopic}/${this.endpointId}/${sendAsync ? "deferredResponse" : "alexaResponce"}`;
-        return new Promise((resolve) => {
-            this.mqttClient.publish(topic, JSON.stringify(payload), (err) => {
-                if (!err)
-                    return resolve(topic);
-                if (this.onPublishError)
-                    this.onPublishError(err); // -> the bridge's "error" event (when somebody listens)
-                resolve(""); // 1.5.1 rejected here, and an un-caught send() then killed the host on any broker hiccup
-            });
-        });
+        const answer = sendAsync ? topics.deferred : topics.response;
+        const build = () => sceneEvent({ endpointId: this.endpointId, correlationToken, activated, cause });
+        return send(this.publisher, answer(this.rootTopic, this.endpointId), build, this.onPublishError);
     }
     /** The capabilities the device declared, in the order it declared them. */
     getCapabilities() {
diff --git a/dist/esm/index.d.ts b/dist/esm/index.d.ts
index 8a97471..a718bc1 100644
--- a/dist/esm/index.d.ts
+++ b/dist/esm/index.d.ts
@@ -13,6 +13,9 @@ export type { ActionId, AssetId, DisplayCategoryName, StateId, UnitOfMeasure, Ac
 export * as messages from "./messages/index.js";
 export { AlexaError, AlexaErrors, MessageError, StateBuilder, property } from "./messages/index.js";
 export type { ChangeCause, ChangeReportMessage, DeferredResponseMessage, ErrorResponseMessage, Header, ProactiveEventMessage, Property, PropertyOptions, ResponseMessage, SceneEventMessage, } from "./messages/index.js";
+export * as topics from "./topics.js";
+export { MemoryPublisher } from "./transport.js";
+export type { Publisher, PublishResult } from "./transport.js";
 export { AlexaInterface } from "./compat/AlexaInterface.js";
 export type { SupportedMode } from "./compat/AlexaInterface.js";
 export { ActionMapping } from "./compat/ActionMapping.js";
diff --git a/dist/esm/index.js b/dist/esm/index.js
index e522d0b..fa09b61 100644
--- a/dist/esm/index.js
+++ b/dist/esm/index.js
@@ -12,6 +12,9 @@ export { ASSETS as Assets, UNITS_OF_MEASURE as Units, ACTIONS as Actions, STATES
 // The messages: what the bridge publishes, built from plain values
 export * as messages from "./messages/index.js";
 export { AlexaError, AlexaErrors, MessageError, StateBuilder, property } from "./messages/index.js";
+// Publishing: the topics of the Alex2MQTT contract, and a publisher that needs no broker for tests
+export * as topics from "./topics.js";
+export { MemoryPublisher } from "./transport.js";
 // 1.x
 export { AlexaInterface } from "./compat/AlexaInterface.js";
 export { ActionMapping } from "./compat/ActionMapping.js";
diff --git a/dist/esm/topics.d.ts b/dist/esm/topics.d.ts
new file mode 100644
index 0000000..14bb390
--- /dev/null
+++ b/dist/esm/topics.d.ts
@@ -0,0 +1,8 @@
+/** Where the bridge answers a discovery request with its endpoints. */
+export declare const discoverReply: (root: string) => string;
+/** Where the answer to a directive goes. "alexaResponce" is how the backend and Alex2ESP spell it. */
+export declare const response: (root: string, endpointId: string) => string;
+/** Where the answer goes once a DeferredResponse was sent for the directive. */
+export declare const deferred: (root: string, endpointId: string) => string;
+/** Where every ChangeReport of the root goes: the backend adds the user's token and posts it to Alexa. */
+export declare const changeReport: (root: string) => string;
diff --git a/dist/esm/topics.js b/dist/esm/topics.js
new file mode 100644
index 0000000..ba81060
--- /dev/null
+++ b/dist/esm/topics.js
@@ -0,0 +1,10 @@
+// The topics of the Alex2MQTT contract, named once. The backend and Alex2ESP use the same names, so none of them
+// can change here alone.
+/** Where the bridge answers a discovery request with its endpoints. */
+export const discoverReply = (root) => `${root}/discover_r`;
+/** Where the answer to a directive goes. "alexaResponce" is how the backend and Alex2ESP spell it. */
+export const response = (root, endpointId) => `${root}/${endpointId}/alexaResponce`;
+/** Where the answer goes once a DeferredResponse was sent for the directive. */
+export const deferred = (root, endpointId) => `${root}/${endpointId}/deferredResponse`;
+/** Where every ChangeReport of the root goes: the backend adds the user's token and posts it to Alexa. */
+export const changeReport = (root) => `${root}/changeReport`;
diff --git a/dist/esm/transport.d.ts b/dist/esm/transport.d.ts
new file mode 100644
index 0000000..6c2ad3c
--- /dev/null
+++ b/dist/esm/transport.d.ts
@@ -0,0 +1,48 @@
+import type { MqttClient } from "mqtt";
+/** What became of a publish. A failure is a value: publish() never rejects. */
+export type PublishResult = {
+    ok: true;
+    topic: string;
+} | {
+    ok: false;
+    topic: string;
+    error: Error;
+};
+/** Where the bridge, its devices and their messages publish. The message is sent as JSON. */
+export interface Publisher {
+    publish(topic: string, message: object): Promise<PublishResult>;
+}
+/**
+ * Publishes to the broker through the client the bridge has at the time: a new one after disconnect() and connect(),
+ * none before connect() and after disconnect(). Without a client the publish is refused. With a client that lost
+ * its connection mqtt.js keeps the message and sends it after the reconnect, and the publish resolves then.
+ */
+export declare class MqttPublisher implements Publisher {
+    private readonly client;
+    constructor(client: () => MqttClient | null);
+    publish(topic: string, message: object): Promise<PublishResult>;
+}
+/**
+ * Keeps what it is asked to publish, for tests and dry runs without a broker:
+ *
+ *   const sent = new MemoryPublisher();
+ *   device.publisher = sent;
+ *   await device.getStatusMessage(token, true).addPowerControllerProp(PowerController.ON).send();
+ *   sent.published[0]   // { topic: "<root>/<endpointId>/alexaResponce", message: { event, context } }
+ */
+export declare class MemoryPublisher implements Publisher {
+    /** Oldest first. The message is what a subscriber gets after JSON.parse. */
+    readonly published: Array<{
+        topic: string;
+        message: any;
+    }>;
+    /** Set it and every publish fails with this error, as a publish to a broker that is gone does. */
+    failWith: Error | null;
+    publish(topic: string, message: object): Promise<PublishResult>;
+}
+/**
+ * send() as 1.x promises it: resolves with the topic, or with "" when nothing was published, and never rejects
+ * (1.5.1 rejected, and a send() nobody caught killed the host on any broker hiccup). What went wrong goes to report:
+ * the message cannot be built, the device is on no bridge, or the publish failed.
+ */
+export declare function send(publisher: Publisher | null, topic: string, build: () => object, report?: (err: Error) => void): Promise<string>;
diff --git a/dist/esm/transport.js b/dist/esm/transport.js
new file mode 100644
index 0000000..403cef3
--- /dev/null
+++ b/dist/esm/transport.js
@@ -0,0 +1,77 @@
+const asError = (err) => (err instanceof Error ? err : new Error(String(err)));
+/**
+ * Publishes to the broker through the client the bridge has at the time: a new one after disconnect() and connect(),
+ * none before connect() and after disconnect(). Without a client the publish is refused. With a client that lost
+ * its connection mqtt.js keeps the message and sends it after the reconnect, and the publish resolves then.
+ */
+export class MqttPublisher {
+    constructor(client) {
+        this.client = client;
+    }
+    publish(topic, message) {
+        const client = this.client();
+        return new Promise((resolve) => {
+            const failed = (err) => resolve({ ok: false, topic, error: asError(err) });
+            if (!client) {
+                failed(new Error(`nothing was published to ${topic}: the bridge is not connected, call connect() first`));
+                return;
+            }
+            try {
+                client.publish(topic, JSON.stringify(message), (err) => (err ? failed(err) : resolve({ ok: true, topic })));
+            }
+            catch (err) {
+                failed(err);
+            }
+        });
+    }
+}
+/**
+ * Keeps what it is asked to publish, for tests and dry runs without a broker:
+ *
+ *   const sent = new MemoryPublisher();
+ *   device.publisher = sent;
+ *   await device.getStatusMessage(token, true).addPowerControllerProp(PowerController.ON).send();
+ *   sent.published[0]   // { topic: "<root>/<endpointId>/alexaResponce", message: { event, context } }
+ */
+export class MemoryPublisher {
+    constructor() {
+        /** Oldest first. The message is what a subscriber gets after JSON.parse. */
+        this.published = [];
+        /** Set it and every publish fails with this error, as a publish to a broker that is gone does. */
+        this.failWith = null;
+    }
+    publish(topic, message) {
+        if (this.failWith)
+            return Promise.resolve({ ok: false, topic, error: this.failWith });
+        try {
+            this.published.push({ topic, message: JSON.parse(JSON.stringify(message)) });
+        }
+        catch (err) {
+            return Promise.resolve({ ok: false, topic, error: asError(err) });
+        }
+        return Promise.resolve({ ok: true, topic });
+    }
+}
+/**
+ * send() as 1.x promises it: resolves with the topic, or with "" when nothing was published, and never rejects
+ * (1.5.1 rejected, and a send() nobody caught killed the host on any broker hiccup). What went wrong goes to report:
+ * the message cannot be built, the device is on no bridge, or the publish failed.
+ */
+export async function send(publisher, topic, build, report) {
+    let result;
+    try {
+        const message = build();
+        if (!publisher) {
+            throw new Error(`nothing was published to ${topic}: the device is on no bridge, register it with addDevice() or registerDevice()`);
+        }
+        result = await publisher.publish(topic, message);
+    }
+    catch (err) {
+        result = { ok: false, topic, error: asError(err) };
+    }
+    if (result.ok)
+        return topic;
+    if (report)
+        report(result.error);
+    return "";
+}
diff --git a/dist/types/Alex2Node.d.ts b/dist/types/Alex2Node.d.ts
index 983e964..e7d45dc 100644
--- a/dist/types/Alex2Node.d.ts
+++ b/dist/types/Alex2Node.d.ts
@@ -38,6 +38,7 @@ declare class Alex2MQTT extends EventEmitter {
     private rootTopic;
     private debugLogging;
     private client;
+    private readonly publisher;
     private devices;
     private MqttHost;
     private options;
@@ -62,7 +63,8 @@ declare class Alex2MQTT extends EventEmitter {
      *
      * Throws a DeclarationError when Alexa would reject the endpoint (an endpointId with a slash, a name with
      * punctuation) or when the endpointId is registered already. Discovery lists Alexa.EndpointHealth for the device
-     * unless endpointHealth is false.
+     * unless endpointHealth is false. A device can be declared before connect(): what it sends before the bridge has
+     * a connection is not published, and the "error" event says so.
      */
     addDevice(definition: EndpointDefinition): Device;
     registerDevice(name: string, endpointId: string, displayCategory?: DisplayCategory | DisplayCategory[] | null): Device;
@@ -71,6 +73,7 @@ declare class Alex2MQTT extends EventEmitter {
     unregisterDevice(endpointId: string): boolean;
     /** Forget every device. */
     clearDevices(): void;
+    private release;
     getDevices(): Device[];
     getDevice(endpointId: string): Device | undefined;
     getRootTopic(): string;
diff --git a/dist/types/compat/AlexaErrorResponse.d.ts b/dist/types/compat/AlexaErrorResponse.d.ts
index 389b6cc..696f1ea 100644
--- a/dist/types/compat/AlexaErrorResponse.d.ts
+++ b/dist/types/compat/AlexaErrorResponse.d.ts
@@ -1,17 +1,17 @@
-import type { MqttClient } from "mqtt";
 import type { ErrorResponseMessage } from "../messages/types.js";
+import type { Publisher } from "../transport.js";
 /** An ErrorResponse as 1.x builds it: device.getErrorMessage(token), setErrorMessage(), send(). */
 export declare class AlexaErrorResponse {
     private readonly correlationToken;
     private readonly rootTopic;
     private readonly endpointId;
-    private readonly mqttClient;
+    private readonly publisher;
     private error;
     private namespace?;
     private readonly messageId;
     /** Where a failed publish is reported (set by the Device that built this message, 1.5.2): send() never rejects. */
     onPublishError?: (err: Error) => void;
-    constructor(correlationToken: string, rootTopic: string, endpointId: string, mqttClient: MqttClient);
+    constructor(correlationToken: string, rootTopic: string, endpointId: string, publisher: Publisher | null);
     /**
      * The error to answer with. otherParams are the fields the type adds to the payload (validRange). The header
      * carries the namespace the type is documented under, Alexa.ThermostatController for THERMOSTAT_IS_OFF;
diff --git a/dist/types/compat/AlexaStatusMessage.d.ts b/dist/types/compat/AlexaStatusMessage.d.ts
index f4dee17..2f9e51a 100644
--- a/dist/types/compat/AlexaStatusMessage.d.ts
+++ b/dist/types/compat/AlexaStatusMessage.d.ts
@@ -1,5 +1,5 @@
-import type { MqttClient } from "mqtt";
 import type { ChangeCause, Property } from "../messages/types.js";
+import type { Publisher } from "../transport.js";
 import { TemperatureSensorScale } from "./enums.js";
 import type { EndpointHealth, PowerController } from "./enums.js";
 /**
@@ -10,7 +10,7 @@ export declare class AlexaStatusMessage {
     private readonly correlationToken;
     private readonly rootTopic;
     private readonly endpointId;
-    private readonly mqttClient;
+    private readonly publisher;
     private readonly isResponse;
     private readonly isDeferred;
     private readonly changeCause;
@@ -19,7 +19,7 @@ export declare class AlexaStatusMessage {
     private estimatedDeferralInSeconds?;
     /** Where a failed publish is reported (set by the Device that built this message, 1.5.2): send() never rejects. */
     onPublishError?: (err: Error) => void;
-    constructor(correlationToken: string, rootTopic: string, endpointId: string, mqttClient: MqttClient, isResponse?: boolean, isDeferred?: boolean, changeCause?: ChangeCause | null);
+    constructor(correlationToken: string, rootTopic: string, endpointId: string, publisher: Publisher | null, isResponse?: boolean, isDeferred?: boolean, changeCause?: ChangeCause | null);
     private addProperty;
     /** ChangeReport: the add*Prop calls that follow describe what CHANGED (the default for a change report). */
     changed(): this;
diff --git a/dist/types/device/Device.d.ts b/dist/types/device/Device.d.ts
index f404968..5f0d570 100644
--- a/dist/types/device/Device.d.ts
+++ b/dist/types/device/Device.d.ts
@@ -1,5 +1,4 @@
 import { EventEmitter } from "events";
-import type { MqttClient } from "mqtt";
 import { AlexaErrorResponse } from "../compat/AlexaErrorResponse.js";
 import { AlexaInterface } from "../compat/AlexaInterface.js";
 import { AlexaStatusMessage } from "../compat/AlexaStatusMessage.js";
@@ -8,6 +7,7 @@ import type { AlexaInterfaceType } from "../compat/enums.js";
 import type { ChangeCause } from "../messages/types.js";
 import type { DisplayCategoryName } from "../registry/catalog.js";
 import type { Directives, InterfaceDescriptor, Properties } from "../registry/types.js";
+import type { Publisher } from "../transport.js";
 import { Capability } from "./Capability.js";
 import type { AnyCapability, CapabilityJson, Declaration } from "./Capability.js";
 import type { EndpointFields } from "./validate.js";
@@ -40,7 +40,6 @@ export interface EndpointJson extends EndpointFields {
 }
 type DeclarationArguments<O, I extends boolean> = {} extends Declaration<O, I> ? [options?: Declaration<O, I>] : [options: Declaration<O, I>];
 declare class Device extends EventEmitter {
-    private mqttClient;
     private rootTopic;
     name: string;
     endpointId: string;
@@ -67,9 +66,14 @@ declare class Device extends EventEmitter {
     private capabilities;
     /** Where a failed publish from this device or a message it built is reported; Alex2MQTT sets it (1.5.2). */
     onPublishError?: (err: Error) => void;
-    constructor(mqttClient: MqttClient, rootTopic: string, name: string, endpointId: string, displayCategory: Array<DisplayCategory> | null, description?: string, manufacturerName?: string, manufacturer?: string, model?: string);
-    /** Internal (1.5.2): Alex2MQTT.connect() re-binds every registered device to its new broker client after a disconnect(). */
-    setMqttClient(client: MqttClient): void;
+    /**
+     * What the device and the messages it builds publish through. The bridge sets it when the device is registered
+     * and clears it when the device is unregistered; a MemoryPublisher here tests a device without a broker. While it
+     * is null every send() resolves "" and reports why.
+     */
+    publisher: Publisher | null;
+    /** client is ignored: in 1.x it was the broker client, and a device could only be built after connect(). */
+    constructor(client: unknown, rootTopic: string, name: string, endpointId: string, displayCategory: Array<DisplayCategory> | null, description?: string, manufacturerName?: string, manufacturer?: string, model?: string);
     getName(): string;
     setName(name: string): void;
     getEndpointId(): string;
diff --git a/dist/types/index.d.ts b/dist/types/index.d.ts
index 8a97471..a718bc1 100644
--- a/dist/types/index.d.ts
+++ b/dist/types/index.d.ts
@@ -13,6 +13,9 @@ export type { ActionId, AssetId, DisplayCategoryName, StateId, UnitOfMeasure, Ac
 export * as messages from "./messages/index.js";
 export { AlexaError, AlexaErrors, MessageError, StateBuilder, property } from "./messages/index.js";
 export type { ChangeCause, ChangeReportMessage, DeferredResponseMessage, ErrorResponseMessage, Header, ProactiveEventMessage, Property, PropertyOptions, ResponseMessage, SceneEventMessage, } from "./messages/index.js";
+export * as topics from "./topics.js";
+export { MemoryPublisher } from "./transport.js";
+export type { Publisher, PublishResult } from "./transport.js";
 export { AlexaInterface } from "./compat/AlexaInterface.js";
 export type { SupportedMode } from "./compat/AlexaInterface.js";
 export { ActionMapping } from "./compat/ActionMapping.js";
diff --git a/dist/types/topics.d.ts b/dist/types/topics.d.ts
new file mode 100644
index 0000000..14bb390
--- /dev/null
+++ b/dist/types/topics.d.ts
@@ -0,0 +1,8 @@
+/** Where the bridge answers a discovery request with its endpoints. */
+export declare const discoverReply: (root: string) => string;
+/** Where the answer to a directive goes. "alexaResponce" is how the backend and Alex2ESP spell it. */
+export declare const response: (root: string, endpointId: string) => string;
+/** Where the answer goes once a DeferredResponse was sent for the directive. */
+export declare const deferred: (root: string, endpointId: string) => string;
+/** Where every ChangeReport of the root goes: the backend adds the user's token and posts it to Alexa. */
+export declare const changeReport: (root: string) => string;
diff --git a/dist/types/transport.d.ts b/dist/types/transport.d.ts
new file mode 100644
index 0000000..6c2ad3c
--- /dev/null
+++ b/dist/types/transport.d.ts
@@ -0,0 +1,48 @@
+import type { MqttClient } from "mqtt";
+/** What became of a publish. A failure is a value: publish() never rejects. */
+export type PublishResult = {
+    ok: true;
+    topic: string;
+} | {
+    ok: false;
+    topic: string;
+    error: Error;
+};
+/** Where the bridge, its devices and their messages publish. The message is sent as JSON. */
+export interface Publisher {
+    publish(topic: string, message: object): Promise<PublishResult>;
+}
+/**
+ * Publishes to the broker through the client the bridge has at the time: a new one after disconnect() and connect(),
+ * none before connect() and after disconnect(). Without a client the publish is refused. With a client that lost
+ * its connection mqtt.js keeps the message and sends it after the reconnect, and the publish resolves then.
+ */
+export declare class MqttPublisher implements Publisher {
+    private readonly client;
+    constructor(client: () => MqttClient | null);
+    publish(topic: string, message: object): Promise<PublishResult>;
+}
+/**
+ * Keeps what it is asked to publish, for tests and dry runs without a broker:
+ *
+ *   const sent = new MemoryPublisher();
+ *   device.publisher = sent;
+ *   await device.getStatusMessage(token, true).addPowerControllerProp(PowerController.ON).send();
+ *   sent.published[0]   // { topic: "<root>/<endpointId>/alexaResponce", message: { event, context } }
+ */
+export declare class MemoryPublisher implements Publisher {
+    /** Oldest first. The message is what a subscriber gets after JSON.parse. */
+    readonly published: Array<{
+        topic: string;
+        message: any;
+    }>;
+    /** Set it and every publish fails with this error, as a publish to a broker that is gone does. */
+    failWith: Error | null;
+    publish(topic: string, message: object): Promise<PublishResult>;
+}
+/**
+ * send() as 1.x promises it: resolves with the topic, or with "" when nothing was published, and never rejects
+ * (1.5.1 rejected, and a send() nobody caught killed the host on any broker hiccup). What went wrong goes to report:
+ * the message cannot be built, the device is on no bridge, or the publish failed.
+ */
+export declare function send(publisher: Publisher | null, topic: string, build: () => object, report?: (err: Error) => void): Promise<string>;
diff --git a/src/Alex2Node.ts b/src/Alex2Node.ts
index ed2c782..c05f6f5 100644
--- a/src/Alex2Node.ts
+++ b/src/Alex2Node.ts
@@ -7,6 +7,8 @@ import { checkEndpoint } from "./device/validate.js";
 import { EventEmitter } from "events";
 import { DisplayCategory } from "./compat/enums.js";
 import { DeclarationError } from "./registry/types.js";
+import * as topics from "./topics.js";
+import { MqttPublisher } from "./transport.js";
 
 /** Optional settings for the bridge (1.5.1). Everything has the 1.4.0 behaviour as its default. */
 export interface Alex2MQTTOptions {
@@ -47,6 +49,8 @@ const DESCRIBED = [
  */
 class Alex2MQTT extends EventEmitter {
   private client: MqttClient | null = null;
+  // One for the life of the bridge: the devices keep it over disconnect() and connect()
+  private readonly publisher = new MqttPublisher(() => this.client);
   private devices: Device[] = [];
   private MqttHost: string;
   private options: Alex2MQTTOptions;
@@ -93,7 +97,6 @@ class Alex2MQTT extends EventEmitter {
     };
 
     this.client = mqtt.connect(this.MqttHost, options);
-    for (const d of this.devices) d.setMqttClient(this.client); // after a disconnect(): the devices publish through the new client
 
     this.client.on("connect", () => {
       this.connected = true;
@@ -115,9 +118,9 @@ class Alex2MQTT extends EventEmitter {
         this.log("Discovery request received, getting device json...");
         const deviceArray = this.describeDevices();
         this.lastDiscoveryAt = new Date().toISOString();
-        this.client!.publish(topic + "_r", JSON.stringify(deviceArray), (err) => {
-          if (err) { this.fail(err); return; }
-          this.log(`Discovery payloads published to ${topic + "_r"}`, deviceArray);
+        void this.publisher.publish(topics.discoverReply(this.rootTopic), deviceArray).then((result) => {
+          if (!result.ok) { this.fail(result.error); return; }
+          this.log(`Discovery payloads published to ${result.topic}`, deviceArray);
           this.emit("discover", deviceArray.length);
         });
       } else if (topic.split("/").length == 3) {
@@ -187,15 +190,13 @@ class Alex2MQTT extends EventEmitter {
    *
    * Throws a DeclarationError when Alexa would reject the endpoint (an endpointId with a slash, a name with
    * punctuation) or when the endpointId is registered already. Discovery lists Alexa.EndpointHealth for the device
-   * unless endpointHealth is false.
+   * unless endpointHealth is false. A device can be declared before connect(): what it sends before the bridge has
+   * a connection is not published, and the "error" event says so.
    */
   addDevice(definition: EndpointDefinition): Device {
-    if (!this.client) {
-      throw new Error("Must call connect before creating devices");
-    }
     const { endpointId, name, categories, endpointHealth, ...described } = definition;
     // Without categories the device would take LIGHT, the default of registerDevice: here it is a mistake
-    const device = new Device(this.client, this.rootTopic, name, endpointId, (categories ?? []) as DisplayCategory[]);
+    const device = new Device(null, this.rootTopic, name, endpointId, (categories ?? []) as DisplayCategory[]);
     for (const [field, value] of Object.entries(described)) {
       if (!DESCRIBED.includes(field)) throw new DeclarationError({ endpointId }, `${field} is not a field of an endpoint`);
       if (value !== undefined) Object.assign(device, { [field]: value });
@@ -212,9 +213,6 @@ class Alex2MQTT extends EventEmitter {
     endpointId: string,
     displayCategory?: DisplayCategory | DisplayCategory[] | null
   ): Device {
-    if (!this.client) {
-      throw new Error("Must call connect before creating devices");
-    }
     const existing = this.devices.find((d) => d.endpointId === endpointId);
     if (existing) { // 1.5.2: endpointIds are unique per root topic; 1.5.1 added a second device that never got a directive
       const warning = `warning: registerDevice("${endpointId}") is already registered as "${existing.name}", returning that device`;
@@ -223,7 +221,7 @@ class Alex2MQTT extends EventEmitter {
     }
     this.log(`Creating new device with endpoint: ${endpointId}`);
     const normalizedCategory = Array.isArray(displayCategory) ? displayCategory : [displayCategory || DisplayCategory.LIGHT];
-    const device = new Device(this.client, this.rootTopic, name, endpointId, normalizedCategory);
+    const device = new Device(null, this.rootTopic, name, endpointId, normalizedCategory);
     this.register(device, false);
     return device;
   }
@@ -232,6 +230,7 @@ class Alex2MQTT extends EventEmitter {
     device.alexaInterface = this.options.alexaInterface !== false;
     device.endpointHealth = endpointHealth;
     device.onPublishError = (err) => this.fail(err); // a failed publish is an "error" event (when listened to), never a rejected send()
+    device.publisher = this.publisher;
     this.devices.push(device);
   }
 
@@ -239,15 +238,20 @@ class Alex2MQTT extends EventEmitter {
   unregisterDevice(endpointId: string): boolean {
     const i = this.devices.findIndex((d) => d.endpointId === endpointId);
     if (i === -1) return false;
-    this.devices[i].removeAllListeners();
+    this.release(this.devices[i]);
     this.devices.splice(i, 1);
     return true;
   }
   /** Forget every device. */
   clearDevices(): void {
-    for (const d of this.devices) d.removeAllListeners();
+    for (const d of this.devices) this.release(d);
     this.devices = [];
   }
+  // A device the bridge forgot hears no directive and publishes nothing
+  private release(device: Device): void {
+    device.removeAllListeners();
+    device.publisher = null;
+  }
   getDevices(): Device[] {
     return this.devices.slice();
   }
diff --git a/src/compat/AlexaErrorResponse.ts b/src/compat/AlexaErrorResponse.ts
index b466662..e9c94f7 100644
--- a/src/compat/AlexaErrorResponse.ts
+++ b/src/compat/AlexaErrorResponse.ts
@@ -1,9 +1,11 @@
 import { randomUUID } from "crypto";
-import type { MqttClient } from "mqtt";
 import { errorResponse } from "../messages/build.js";
 import { AlexaErrors } from "../messages/errors.js";
 import type { AlexaError } from "../messages/errors.js";
 import type { ErrorResponseMessage } from "../messages/types.js";
+import * as topics from "../topics.js";
+import { send } from "../transport.js";
+import type { Publisher } from "../transport.js";
 
 /** An ErrorResponse as 1.x builds it: device.getErrorMessage(token), setErrorMessage(), send(). */
 export class AlexaErrorResponse {
@@ -19,7 +21,7 @@ export class AlexaErrorResponse {
     private readonly correlationToken: string,
     private readonly rootTopic: string,
     private readonly endpointId: string,
-    private readonly mqttClient: MqttClient
+    private readonly publisher: Publisher | null
   ) {}
 
   /**
@@ -52,13 +54,7 @@ export class AlexaErrorResponse {
 
   /** Resolves with the topic published to, or "" when the publish failed. Never rejects. */
   send(sendAsync = false): Promise<string> {
-    const topic = `${this.rootTopic}/${this.endpointId}/${sendAsync ? "deferredResponse" : "alexaResponce"}`; // "alexaResponce" is how Alex2MQTT and Alex2ESP spell the topic
-    return new Promise((resolve) => {
-      this.mqttClient.publish(topic, JSON.stringify(this.toJSON()), (err) => {
-        if (!err) return resolve(topic);
-        if (this.onPublishError) this.onPublishError(err); // -> the bridge's "error" event (when somebody listens)
-        resolve(""); // 1.5.1 rejected here, and an un-caught send() then killed the host on any broker hiccup
-      });
-    });
+    const answer = sendAsync ? topics.deferred : topics.response;
+    return send(this.publisher, answer(this.rootTopic, this.endpointId), () => this.toJSON(), this.onPublishError);
   }
 }
diff --git a/src/compat/AlexaStatusMessage.ts b/src/compat/AlexaStatusMessage.ts
index 9c23f3b..7d3d399 100644
--- a/src/compat/AlexaStatusMessage.ts
+++ b/src/compat/AlexaStatusMessage.ts
@@ -1,8 +1,10 @@
 import { randomUUID } from "crypto";
-import type { MqttClient } from "mqtt";
 import { changeReport, deferredResponse, response } from "../messages/build.js";
 import { StateBuilder } from "../messages/StateBuilder.js";
 import type { ChangeCause, Property } from "../messages/types.js";
+import * as topics from "../topics.js";
+import { send } from "../transport.js";
+import type { Publisher } from "../transport.js";
 import { AlexaInterfaceType, TemperatureSensorScale } from "./enums.js";
 import type { EndpointHealth, PowerController } from "./enums.js";
 
@@ -27,7 +29,7 @@ export class AlexaStatusMessage {
     private readonly correlationToken: string,
     private readonly rootTopic: string,
     private readonly endpointId: string,
-    private readonly mqttClient: MqttClient,
+    private readonly publisher: Publisher | null,
     private readonly isResponse: boolean = false,
     private readonly isDeferred: boolean = false,
     private readonly changeCause: ChangeCause | null = null
@@ -139,21 +141,8 @@ export class AlexaStatusMessage {
    * to). Never rejects (1.5.1 did, so an un-caught send() could kill the host).
    */
   public send(sendAsync: boolean = false): Promise<string> {
-    const topic = this.changeCause
-      ? `${this.rootTopic}/changeReport`
-      : `${this.rootTopic}/${this.endpointId}/${sendAsync ? "deferredResponse" : "alexaResponce"}`; // "alexaResponce" is how Alex2MQTT and Alex2ESP spell the topic
-    return new Promise((resolve) => {
-      const failed = (err: Error): void => {
-        if (this.onPublishError) this.onPublishError(err); // -> the bridge's "error" event (when somebody listens)
-        resolve(""); // 1.5.1 rejected here, and an un-caught send() then killed the host on any broker hiccup
-      };
-      let payload: string;
-      try {
-        payload = JSON.stringify(this.toJSON());
-      } catch (err) {
-        return failed(err as Error);
-      }
-      this.mqttClient.publish(topic, payload, (err) => (err ? failed(err) : resolve(topic)));
-    });
+    const answer = sendAsync ? topics.deferred : topics.response;
+    const topic = this.changeCause ? topics.changeReport(this.rootTopic) : answer(this.rootTopic, this.endpointId);
+    return send(this.publisher, topic, () => this.toJSON(), this.onPublishError);
   }
 }
diff --git a/src/device/Device.ts b/src/device/Device.ts
index 3a9cb26..8515648 100644
--- a/src/device/Device.ts
+++ b/src/device/Device.ts
@@ -1,5 +1,4 @@
 import { EventEmitter } from "events";
-import type { MqttClient } from "mqtt";
 import { AlexaErrorResponse } from "../compat/AlexaErrorResponse.js";
 import { AlexaInterface } from "../compat/AlexaInterface.js";
 import { AlexaStatusMessage } from "../compat/AlexaStatusMessage.js";
@@ -13,6 +12,9 @@ import { EndpointHealth } from "../registry/interfaces/EndpointHealth.js";
 import { SchemaError } from "../registry/schema.js";
 import { DeclarationError } from "../registry/types.js";
 import type { Directives, EndpointView, InterfaceDescriptor, Label, Properties } from "../registry/types.js";
+import * as topics from "../topics.js";
+import { send } from "../transport.js";
+import type { Publisher } from "../transport.js";
 import { Capability, commonOptions } from "./Capability.js";
 import type { AnyCapability, CapabilityJson, Declaration } from "./Capability.js";
 import { checkCapability, checkCapabilityCount, checkEndpoint } from "./validate.js";
@@ -72,9 +74,16 @@ class Device extends EventEmitter {
   private capabilities: AnyCapability[] = [];
   /** Where a failed publish from this device or a message it built is reported; Alex2MQTT sets it (1.5.2). */
   public onPublishError?: (err: Error) => void;
+  /**
+   * What the device and the messages it builds publish through. The bridge sets it when the device is registered
+   * and clears it when the device is unregistered; a MemoryPublisher here tests a device without a broker. While it
+   * is null every send() resolves "" and reports why.
+   */
+  public publisher: Publisher | null = null;
 
+  /** client is ignored: in 1.x it was the broker client, and a device could only be built after connect(). */
   constructor(
-    private mqttClient: MqttClient,
+    client: unknown,
     private rootTopic: string,
     public name: string,
     public endpointId: string,
@@ -87,11 +96,6 @@ class Device extends EventEmitter {
     super();
   }
 
-  /** Internal (1.5.2): Alex2MQTT.connect() re-binds every registered device to its new broker client after a disconnect(). */
-  setMqttClient(client: MqttClient): void {
-    this.mqttClient = client;
-  }
-
   getName(): string {
     return this.name;
   }
@@ -124,7 +128,7 @@ class Device extends EventEmitter {
       correlationToken,
       this.rootTopic,
       this.endpointId,
-      this.mqttClient
+      this.publisher
     );
     msg.onPublishError = this.onPublishError;
     return msg;
@@ -138,7 +142,7 @@ class Device extends EventEmitter {
       correlationToken,
       this.rootTopic,
       this.endpointId,
-      this.mqttClient,
+      this.publisher,
       isResponse,
       isDeferred
     );
@@ -152,7 +156,7 @@ class Device extends EventEmitter {
    * Without a changed property send() publishes nothing and resolves with "": Alex2MQTT would drop the report.
    */
   getChangeReport(cause: ChangeCause = "PHYSICAL_INTERACTION"): AlexaStatusMessage {
-    const msg = new AlexaStatusMessage("", this.rootTopic, this.endpointId, this.mqttClient, false, false, cause);
+    const msg = new AlexaStatusMessage("", this.rootTopic, this.endpointId, this.publisher, false, false, cause);
     msg.onPublishError = this.onPublishError;
     return msg;
   }
@@ -161,15 +165,9 @@ class Device extends EventEmitter {
    * (1.5.1). Resolves with the topic published to, or "" when the publish failed (never rejects, 1.5.2).
    */
   sendSceneResponse(correlationToken: string, activated: boolean, cause: ChangeCause = "VOICE_INTERACTION", sendAsync = false): Promise<string> {
-    const payload = sceneEvent({ endpointId: this.endpointId, correlationToken, activated, cause });
-    const topic = `${this.rootTopic}/${this.endpointId}/${sendAsync ? "deferredResponse" : "alexaResponce"}`;
-    return new Promise((resolve) => {
-      this.mqttClient.publish(topic, JSON.stringify(payload), (err) => {
-        if (!err) return resolve(topic);
-        if (this.onPublishError) this.onPublishError(err); // -> the bridge's "error" event (when somebody listens)
-        resolve(""); // 1.5.1 rejected here, and an un-caught send() then killed the host on any broker hiccup
-      });
-    });
+    const answer = sendAsync ? topics.deferred : topics.response;
+    const build = () => sceneEvent({ endpointId: this.endpointId, correlationToken, activated, cause });
+    return send(this.publisher, answer(this.rootTopic, this.endpointId), build, this.onPublishError);
   }
   /** The capabilities the device declared, in the order it declared them. */
   getCapabilities(): AnyCapability[] {
diff --git a/src/index.ts b/src/index.ts
index efe8fd3..1a1b201 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -34,6 +34,11 @@ export type {
   Property, PropertyOptions, ResponseMessage, SceneEventMessage,
 } from "./messages/index.js";
 
+// Publishing: the topics of the Alex2MQTT contract, and a publisher that needs no broker for tests
+export * as topics from "./topics.js";
+export { MemoryPublisher } from "./transport.js";
+export type { Publisher, PublishResult } from "./transport.js";
+
 // 1.x
 export { AlexaInterface } from "./compat/AlexaInterface.js";
 export type { SupportedMode } from "./compat/AlexaInterface.js";
diff --git a/src/topics.ts b/src/topics.ts
new file mode 100644
index 0000000..25b7e3f
--- /dev/null
+++ b/src/topics.ts
@@ -0,0 +1,14 @@
+// The topics of the Alex2MQTT contract, named once. The backend and Alex2ESP use the same names, so none of them
+// can change here alone.
+
+/** Where the bridge answers a discovery request with its endpoints. */
+export const discoverReply = (root: string): string => `${root}/discover_r`;
+
+/** Where the answer to a directive goes. "alexaResponce" is how the backend and Alex2ESP spell it. */
+export const response = (root: string, endpointId: string): string => `${root}/${endpointId}/alexaResponce`;
+
+/** Where the answer goes once a DeferredResponse was sent for the directive. */
+export const deferred = (root: string, endpointId: string): string => `${root}/${endpointId}/deferredResponse`;
+
+/** Where every ChangeReport of the root goes: the backend adds the user's token and posts it to Alexa. */
+export const changeReport = (root: string): string => `${root}/changeReport`;
diff --git a/src/transport.ts b/src/transport.ts
new file mode 100644
index 0000000..ad56aaf
--- /dev/null
+++ b/src/transport.ts
@@ -0,0 +1,89 @@
+import type { MqttClient } from "mqtt";
+
+/** What became of a publish. A failure is a value: publish() never rejects. */
+export type PublishResult =
+  | { ok: true; topic: string }
+  | { ok: false; topic: string; error: Error };
+
+/** Where the bridge, its devices and their messages publish. The message is sent as JSON. */
+export interface Publisher {
+  publish(topic: string, message: object): Promise<PublishResult>;
+}
+
+const asError = (err: unknown): Error => (err instanceof Error ? err : new Error(String(err)));
+
+/**
+ * Publishes to the broker through the client the bridge has at the time: a new one after disconnect() and connect(),
+ * none before connect() and after disconnect(). Without a client the publish is refused. With a client that lost
+ * its connection mqtt.js keeps the message and sends it after the reconnect, and the publish resolves then.
+ */
+export class MqttPublisher implements Publisher {
+  constructor(private readonly client: () => MqttClient | null) {}
+
+  publish(topic: string, message: object): Promise<PublishResult> {
+    const client = this.client();
+    return new Promise((resolve) => {
+      const failed = (err: unknown): void => resolve({ ok: false, topic, error: asError(err) });
+      if (!client) {
+        failed(new Error(`nothing was published to ${topic}: the bridge is not connected, call connect() first`));
+        return;
+      }
+      try {
+        client.publish(topic, JSON.stringify(message), (err) => (err ? failed(err) : resolve({ ok: true, topic })));
+      } catch (err) {
+        failed(err);
+      }
+    });
+  }
+}
+
+/**
+ * Keeps what it is asked to publish, for tests and dry runs without a broker:
+ *
+ *   const sent = new MemoryPublisher();
+ *   device.publisher = sent;
+ *   await device.getStatusMessage(token, true).addPowerControllerProp(PowerController.ON).send();
+ *   sent.published[0]   // { topic: "<root>/<endpointId>/alexaResponce", message: { event, context } }
+ */
+export class MemoryPublisher implements Publisher {
+  /** Oldest first. The message is what a subscriber gets after JSON.parse. */
+  public readonly published: Array<{ topic: string; message: any }> = [];
+  /** Set it and every publish fails with this error, as a publish to a broker that is gone does. */
+  public failWith: Error | null = null;
+
+  publish(topic: string, message: object): Promise<PublishResult> {
+    if (this.failWith) return Promise.resolve({ ok: false, topic, error: this.failWith });
+    try {
+      this.published.push({ topic, message: JSON.parse(JSON.stringify(message)) });
+    } catch (err) {
+      return Promise.resolve({ ok: false, topic, error: asError(err) });
+    }
+    return Promise.resolve({ ok: true, topic });
+  }
+}
+
+/**
+ * send() as 1.x promises it: resolves with the topic, or with "" when nothing was published, and never rejects
+ * (1.5.1 rejected, and a send() nobody caught killed the host on any broker hiccup). What went wrong goes to report:
+ * the message cannot be built, the device is on no bridge, or the publish failed.
+ */
+export async function send(
+  publisher: Publisher | null,
+  topic: string,
+  build: () => object,
+  report?: (err: Error) => void
+): Promise<string> {
+  let result: PublishResult;
+  try {
+    const message = build();
+    if (!publisher) {
+      throw new Error(`nothing was published to ${topic}: the device is on no bridge, register it with addDevice() or registerDevice()`);
+    }
+    result = await publisher.publish(topic, message);
+  } catch (err) {
+    result = { ok: false, topic, error: asError(err) };
+  }
+  if (result.ok) return topic;
+  if (report) report(result.error);
+  return "";
+}
diff --git a/test/compat/messages.test.js b/test/compat/messages.test.js
index 3cc03f0..4d1016c 100644
--- a/test/compat/messages.test.js
+++ b/test/compat/messages.test.js
@@ -5,7 +5,7 @@ const { test } = require("node:test");
 const assert = require("node:assert/strict");
 const {
   Alex2MQTT, AlexaErrorResponse, AlexaErrorType, AlexaInterfaceType, AlexaStatusMessage, DisplayCategory, EndpointHealth,
-  PowerController, TemperatureSensorScale,
+  MemoryPublisher, PowerController, TemperatureSensorScale,
 } = require("alex2node");
 const { setup, sleep, UUID_V4 } = require("../helpers/harness.js");
 
@@ -28,12 +28,6 @@ const property = (namespace, name, value, more = {}) => (
   { namespace, name, value, timeOfSample: "<time>", uncertaintyInMilliseconds: 0, ...more }
 );
 
-// A client that keeps what it is asked to publish
-function recorder(error) {
-  const published = [];
-  return { published, publish: (topic, payload, done) => { published.push({ topic, payload: JSON.parse(payload) }); done(error); } };
-}
-
 test("a Response with every add...Prop helper: the JSON of 1.5.2", () => {
   const message = new AlexaStatusMessage("ct", "root", "5020AA", null, true)
     .addPowerControllerProp(PowerController.ON)
@@ -131,8 +125,8 @@ test("wire change: the namespace of an ErrorResponse follows the type (1.5.2: al
 });
 
 test("an ErrorResponse with the fields of its type: the JSON of 1.5.2, sent to the topic asked for", async () => {
-  const client = recorder();
-  const error = new AlexaErrorResponse("ct", "root", "5020AA", client);
+  const sent = new MemoryPublisher();
+  const error = new AlexaErrorResponse("ct", "root", "5020AA", sent);
   error.setErrorMessage(AlexaErrorType.VALUE_OUT_OF_RANGE, "too high", { validRange: { minimumValue: 1, maximumValue: 10 } });
   const expected = {
     event: {
@@ -144,7 +138,7 @@ test("an ErrorResponse with the fields of its type: the JSON of 1.5.2, sent to t
   assert.deepEqual(settled(error), expected);
   assert.equal(await error.send(), "root/5020AA/alexaResponce");
   assert.equal(await error.send(true), "root/5020AA/deferredResponse");
-  assert.deepEqual(client.published.map(({ topic, payload }) => [topic, settled(payload)]), [
+  assert.deepEqual(sent.published.map(({ topic, message }) => [topic, settled(message)]), [
     ["root/5020AA/alexaResponce", expected],
     ["root/5020AA/deferredResponse", expected],
   ]);
@@ -157,14 +151,16 @@ test("an ErrorResponse nobody gave a type is an INTERNAL_ERROR", () => {
 });
 
 test("send: the topic of the message; a publish that fails resolves \"\" and is reported, never rejected", async () => {
-  const client = recorder();
-  const status = (...flags) => new AlexaStatusMessage("ct", "root", "5020AA", client, ...flags).addPowerControllerProp(PowerController.ON);
+  const sent = new MemoryPublisher();
+  const status = (...flags) => new AlexaStatusMessage("ct", "root", "5020AA", sent, ...flags).addPowerControllerProp(PowerController.ON);
   assert.equal(await status(true).send(), "root/5020AA/alexaResponce");
   assert.equal(await status(true).send(true), "root/5020AA/deferredResponse");
   assert.equal(await status(false, false, "PHYSICAL_INTERACTION").send(), "root/changeReport");
-  assert.deepEqual(client.published.map(({ payload }) => payload.event.header.name), ["Response", "Response", "ChangeReport"]);
+  assert.deepEqual(sent.published.map(({ message }) => message.event.header.name), ["Response", "Response", "ChangeReport"]);
 
-  const failing = new AlexaStatusMessage("ct", "root", "5020AA", recorder(new Error("broker gone")), true);
+  const gone = new MemoryPublisher();
+  gone.failWith = new Error("broker gone");
+  const failing = new AlexaStatusMessage("ct", "root", "5020AA", gone, true);
   const reported = [];
   failing.onPublishError = (err) => reported.push(err.message);
   assert.equal(await failing.send(), "");
diff --git a/test/connection.test.js b/test/connection.test.js
index fea2f14..c342524 100644
--- a/test/connection.test.js
+++ b/test/connection.test.js
@@ -1,10 +1,10 @@
 "use strict";
-// The broker connection: the default host, an outage reported as events that never crash the host, disconnect() then
-// connect(), and a publish that fails without rejecting.
+// The broker connection: the default host, an outage reported as events that never crash the host, devices declared
+// before connect(), disconnect() then connect(), and a publish that fails without rejecting.
 const { test } = require("node:test");
 const assert = require("node:assert/strict");
 const { Alex2MQTT, AlexaInterfaceType, DisplayCategory, PowerController, DEFAULT_HOST } = require("alex2node");
-const { broker, setup, connected, directive, until, sleep, cleanup } = require("./helpers/harness.js");
+const { broker, watcher, setup, connected, directive, until, sleep, cleanup } = require("./helpers/harness.js");
 
 // Nothing listens on port 1, so every attempt is refused at once.
 const DEAD_BROKER = { host: "mqtt://127.0.0.1:1", mqtt: { reconnectPeriod: 50, connectTimeout: 200 } };
@@ -32,8 +32,27 @@ test("a dead broker: 'offline'/'error' events when listened to, and NO crash whe
   await until(() => seen.includes("ECONNREFUSED") && seen.includes("reconnect"), 3000, "error + reconnect events");
 });
 
-test("registerDevice before connect throws (unchanged from 1.4.0)", () => {
-  assert.throws(() => new Alex2MQTT("u", "p", "root").registerDevice("x", "1", null), /connect before/);
+test("devices declared before connect() (1.x threw): a send() is refused until the bridge connects, then they answer", async () => {
+  const { url } = await broker();
+  const alexa = await watcher(url, "root-early/#");
+  const bridge = new Alex2MQTT("u", "p", "root-early", false, { host: url });
+  const errors = [];
+  bridge.on("error", (e) => errors.push(e.message));
+  const lamp = bridge.registerDevice("Lamp", "lamp-1", DisplayCategory.LIGHT);
+  const plug = bridge.addDevice({ endpointId: "plug-1", name: "Plug", categories: ["SMARTPLUG"] });
+  for (const device of [lamp, plug]) {
+    device.on("Event", (d) => device.getStatusMessage(d.header.correlationToken, true).addPowerControllerProp(PowerController.ON).send());
+  }
+
+  assert.equal(await lamp.getStatusMessage("early", true).addPowerControllerProp(PowerController.ON).send(), "");
+  assert.deepEqual(errors, ["nothing was published to root-early/lamp-1/alexaResponce: the bridge is not connected, call connect() first"]);
+
+  await connected(bridge);
+  for (const id of ["lamp-1", "plug-1"]) {
+    alexa.send("root-early", directive("Alexa.PowerController", "TurnOn", id, `ct-${id}`));
+    await until(() => alexa.on(`root-early/${id}/alexaResponce`).length === 1, 3000, `the response of ${id}`);
+    assert.equal(alexa.on(`root-early/${id}/alexaResponce`)[0].event.header.correlationToken, `ct-${id}`);
+  }
 });
 
 test("disconnect() then connect(): devices registered before still answer (1.5.1 left them on the closed client)", async () => {
@@ -66,7 +85,7 @@ test("1.5.2: a failed publish never rejects send() - it resolves \"\" and reache
   await connected(bridge);
   const lamp = bridge.registerDevice("Lamp", "lamp-send", null);
   lamp.addCapability(AlexaInterfaceType.POWER_CONTROLLER);
-  await bridge.disconnect(); // the device still holds the ended client until the next connect(): every publish now fails
+  await bridge.disconnect(); // the bridge has no client until the next connect(): every publish is refused
 
   const status = await lamp.getStatusMessage("ct", true).addPowerControllerProp(PowerController.ON).send();
   const error = await lamp.getErrorMessage("ct").send();
diff --git a/test/helpers/endpoint.js b/test/helpers/endpoint.js
index d77876c..1b88f64 100644
--- a/test/helpers/endpoint.js
+++ b/test/helpers/endpoint.js
@@ -2,7 +2,7 @@
 // A device that is on no bridge. What a device declares and the discovery JSON it answers with need no broker.
 const { Device } = require("alex2node");
 
-/** The arguments Device takes before the name are the broker client and the root topic of its bridge. */
+/** The arguments Device takes before the name are the broker client of 1.x, ignored, and the root topic of its bridge. */
 function endpoint(endpointId = "lamp-1", name = "Lamp", categories = ["LIGHT"]) {
   return new Device(null, "root", name, endpointId, categories);
 }
diff --git a/test/transport.test.js b/test/transport.test.js
new file mode 100644
index 0000000..852b202
--- /dev/null
+++ b/test/transport.test.js
@@ -0,0 +1,65 @@
+"use strict";
+// Publishing without a broker: MemoryPublisher under a device, a device on no bridge, and the topics by name.
+const { test } = require("node:test");
+const assert = require("node:assert/strict");
+const { Alex2MQTT, MemoryPublisher, PowerController, topics } = require("alex2node");
+const { endpoint } = require("./helpers/endpoint.js");
+
+test("the topics of the contract, \"alexaResponce\" spelt as the backend spells it", () => {
+  assert.equal(topics.discoverReply("root"), "root/discover_r");
+  assert.equal(topics.response("root", "lamp-1"), "root/lamp-1/alexaResponce");
+  assert.equal(topics.deferred("root", "lamp-1"), "root/lamp-1/deferredResponse");
+  assert.equal(topics.changeReport("root"), "root/changeReport");
+});
+
+test("MemoryPublisher: what a device sends, by topic, as a subscriber parses it", async () => {
+  const lamp = endpoint("lamp-1");
+  const sent = lamp.publisher = new MemoryPublisher();
+
+  assert.equal(await lamp.getStatusMessage("ct", true).addPowerControllerProp(PowerController.ON).send(), "root/lamp-1/alexaResponce");
+  assert.equal(await lamp.getErrorMessage("ct").send(true), "root/lamp-1/deferredResponse");
+  assert.equal(await lamp.sendSceneResponse("ct", true), "root/lamp-1/alexaResponce");
+  assert.equal(await lamp.getChangeReport().addPowerControllerProp(PowerController.OFF).send(), "root/changeReport");
+  assert.deepEqual(sent.published.map(({ topic, message }) => [topic, message.event.header.name]), [
+    ["root/lamp-1/alexaResponce", "Response"],
+    ["root/lamp-1/deferredResponse", "ErrorResponse"],
+    ["root/lamp-1/alexaResponce", "ActivationStarted"],
+    ["root/changeReport", "ChangeReport"],
+  ]);
+  assert.deepEqual(await sent.publish("root/x", { a: 1, b: undefined }), { ok: true, topic: "root/x" });
+  assert.deepEqual(sent.published[4].message, { a: 1 });
+});
+
+test("MemoryPublisher.failWith: send() resolves \"\" and the error is reported, nothing is kept", async () => {
+  const lamp = endpoint("lamp-1");
+  const sent = lamp.publisher = new MemoryPublisher();
+  sent.failWith = new Error("broker gone");
+  const reported = [];
+  lamp.onPublishError = (err) => reported.push(err.message);
+
+  assert.equal(await lamp.sendSceneResponse("ct", false), "");
+  assert.equal(await lamp.getErrorMessage("ct").send(), "");
+  assert.deepEqual(reported, ["broker gone", "broker gone"]);
+  assert.deepEqual(sent.published, []);
+});
+
+test("a device on no bridge: send() resolves \"\" and the error says to register it", async () => {
+  const lamp = endpoint("lamp-1");
+  const reported = [];
+  lamp.onPublishError = (err) => reported.push(err.message);
+  assert.equal(await lamp.getStatusMessage("ct", true).send(), "");
+  assert.deepEqual(reported, [
+    "nothing was published to root/lamp-1/alexaResponce: the device is on no bridge, register it with addDevice() or registerDevice()",
+  ]);
+});
+
+test("unregisterDevice and clearDevices take the publisher from the device", () => {
+  const bridge = new Alex2MQTT("u", "p", "root");
+  const lamp = bridge.registerDevice("Lamp", "lamp-1", null);
+  const plug = bridge.registerDevice("Plug", "plug-1", null);
+  assert.ok(lamp.publisher && lamp.publisher === plug.publisher, "one publisher for the devices of a bridge");
+  bridge.unregisterDevice("lamp-1");
+  assert.equal(lamp.publisher, null);
+  bridge.clearDevices();
+  assert.equal(plug.publisher, null);
+});