Learn how MQTT brokers, topics, publish/subscribe, retained messages and availability work—then build ESP32 integrations and reliable home-automation messaging.
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A connected path
Move from fundamentals to device integrations and more reliable systems.
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Published resources open normally. Draft cards are listed for planning, but their article and project pages remain unpublished until they are released.
Build the mental model and get a first working setup before adding complexity.
A complete, broker-agnostic ESP32 MQTT tutorial -- topics, QoS, retained messages, Last Will and Testament, TLS security for production, and a working publish/subscribe example with PubSubClient.
MQTT is the backbone of most smart home systems. This guide shows you how to set up an MQTT broker, connect ESP32, and integrate with Home Assistant from scratch.
Build your first real-hardware Node-RED project: wire an LED to an ESP32, send ON/OFF commands over MQTT, and monitor device status from your flow.
Build an ESP32 automatic plant watering system that monitors soil moisture, triggers a pump, and reports data to Home Assistant via MQTT.
Install Eclipse Mosquitto on Raspberry Pi 5, start the broker as a service, test publish/subscribe locally, and configure remote LAN access with explicit listeners and password authentication. Explains the Mosquitto 2.0 local-only default and safe next steps for TLS.
Master MQTT for IoT with a practical guide to brokers, topics, QoS, retained messages, Last Will, Mosquitto, ESP32/ESP8266 firmware and Raspberry Pi integrations. Start with command-line tests and build toward secure, resilient systems.
Understand MQTT without writing code. Learn how brokers route publish/subscribe messages, how topic hierarchies and wildcards work, what QoS guarantees, when to retain state and how Last Will supports device availability.
Connect Node-RED to a Mosquitto MQTT broker, publish a test message, subscribe to the same topic, and verify the message in Debug. A practical foundation for Raspberry Pi and ESP32 IoT projects.
Control a NodeMCU ESP8266 LED by publishing ON/OFF commands to Mosquitto over MQTT. Configure command and reported-state topics, wire an external LED, test with command-line clients and troubleshoot broker access.
Verify a broker and topic flow before connecting any microcontroller. Use mosquitto_pub and mosquitto_sub in two terminals, inspect topics with MQTT Explorer, and diagnose local versus remote broker access.
Stop hardcoding WiFi credentials. Use the WiFiManager library to give your ESP32 a captive configuration portal: first-boot setup from a phone, saved credentials, custom MQTT fields, a reset button, timeouts and fixes for the common pitfalls.
Learn Node-RED from the first Inject-to-Debug flow to MQTT, live dashboards, ESP32 sensor projects and home automation. Follow a structured beginner-to-advanced path with practical guides, reliability advice and security essentials.
New to Node-RED? Learn how nodes, flows, messages and msg.payload work, then build your first Inject-to-Debug flow with simple diagrams and practical IoT examples.
A beginner-friendly explanation of Blynk 2.0: how templates, devices, datastreams and dashboards fit together, what the free plan really allows, and when to choose Blynk over MQTT or Node-RED.
Combine boards, sensors, brokers, dashboards and state feedback into practical systems.
Build an 8-channel relay dashboard using Node-RED and MQTT with separate command and reported-state topics. Plan reconnect behavior, retained-state policy and safe startup without letting the UI misrepresent the hardware.
Compare Blynk, Node-RED, Home Assistant and MQTT by purpose, hosting, dashboards, automation, offline behavior and maintenance. Choose a practical stack for ESP32 and ESP8266 projects without adding unnecessary components.
Build a WiFi smart switch with an ESP32 and a relay that appears in Home Assistant automatically through MQTT Discovery. Includes a physical button, power-loss state restore, safe relay wiring, full code, an automation and a safety section on mains voltage.
Four ways to connect an ESP32 to Home Assistant without MQTT: ESPHome native API (easiest), REST sensors and switches, webhooks and the Home Assistant REST API. Working YAML and code for each, plus a decision guide and troubleshooting.
Build an ESP32 temperature and humidity sensor that appears in Home Assistant automatically using MQTT Discovery. Includes DHT22 wiring, complete PubSubClient code with availability and reconnect, dashboard setup, an alert automation and troubleshooting.
Control relay channels from MQTT with separate command and reported-state topics. Define a safe startup policy, validate commands, handle retained messages carefully and test the relay controller with low-voltage loads.
Send DHT11 temperature/humidity and BMP280 temperature/pressure from an ESP32 to Node-RED over MQTT, validate JSON telemetry, and build a Dashboard 2.0 view with sensible ranges and clear stale-data status.
Design MQTT topic hierarchies that stay readable as IoT projects grow. Learn device naming, telemetry versus commands, wildcard filters, case sensitivity, retained state and topic permission patterns.
Diagnose MQTT connection failures systematically. Understand broker listener and port problems, PubSubClient rc=-2 and rc=5, authentication, client IDs, topic mismatches and reconnect logs for ESP32, ESP8266, Mosquitto and Node-RED.
Build a real-time ESP32 WebSocket server: push live sensor readings to a browser graph, control an LED from the page, handle reconnects and heartbeats, and learn when WebSockets beat HTTP polling and MQTT.
Use MQTT retained status and Last Will and Testament (LWT) to show whether an ESP32 is online. Configure status topics safely, test unexpected disconnects, and separate availability from sensor freshness and retained commands.
Focus on resilience, security, logging, integrations and maintainable system design.
Turn an ESP32 WROOM into a smart home node that publishes sensor data and receives relay commands via MQTT. Supports Home Assistant auto-discovery, OTA firmware updates, and reconnect logic.
Make an ESP32 MQTT client recover from Wi-Fi and broker outages without long delay() calls. Use millis()-based retry scheduling, capped backoff, unique client IDs, resubscription after reconnect and local work that continues while offline.
Harden a Node-RED deployment with editor authentication, HTTPS or a secure reverse proxy, restricted network access, MQTT security, secret handling and recoverable flow backups. Learn what not to expose to the internet.
Build practical Node-RED automations with scheduled Inject nodes, an LDR-based light rule, hysteresis and context variables. Learn to avoid rapid switching, handle stale readings and decide which state should survive a restart.
Turn PIR sensor events into Node-RED Telegram or email alerts without spamming your inbox. Detect state transitions, add a cooldown and test unavailable-network and repeated-trigger scenarios.
Build a time-series logging path from Node-RED to InfluxDB 2.x and Grafana. Validate MQTT sensor payloads, write measurements with units, configure a least-privilege token and chart trends without confusing missing samples with zero.
MQTT moves messages, Node-RED connects them into logic, and Blynk can provide a mobile-facing device interface. Pick the layer your project needs.
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