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Important - PLEASE READ !!
This repo is for the ESP8266 version. It is no longer maintained and superceeded by version 3 which is based on the ESP32 and located at To upgrade an interface board from version 2 to version 3 take a look at BBQKees's instructions.

EMS-ESP is an open-source firmware for the Espressif ESP8266 and ESP32 microcontroller that communicates with EMS (Energy Management System) based equipment from manufacturers like Bosch, Buderus, Nefit, Junkers, Worcester and Sieger.

version release-date license downloads Average time to resolve an issue Percentage of issues still open

If you like EMS-ESP, please give it a star, or fork it and contribute!

GitHub stars GitHub forks donate

Note, EMS-ESP requires a small hardware circuit that can convert the EMS bus data to be read by the microcontroller. These can be ordered at


  • Compatible with both ESP8266 and ESP32
  • A multi-user secure web interface to change settings and monitor the data
  • A console, accessible via Serial and Telnet for more monitoring
  • Native support for Home Assistant via MQTT Discovery
  • Can run standalone as an independent WiFi Access Point or join an existing WiFi network
  • Easy first-time configuration via a web Captive Portal
  • Support for more than 70 EMS devices (boilers, thermostats, solar modules, mixer modules, heat pumps, gateways)


Web Interface

Telnet Console

In Home Assistant


Refer to the official documentation to how to install the firmware and configure it. The documentation is being constantly updated as new features and settings are added.

You can choose to use an pre-built firmware image or compile the code yourself:

Support Information

If you're looking for support on EMS-ESP there are some options available:


Support Community

  • Discord Server: For support, troubleshooting and general questions. You have better chances to get fast answers from members of the community
  • Search in Issues: You might find an answer to your question by searching current or closed issues

Developer's Community

  • Bug Report: For reporting Bugs
  • Feature Request: For requesting features/functions
  • Troubleshooting: As a last resort, you can open new Troubleshooting & Question issue on GitHub if the solution could not be found using the other channels. Just remember: the more info you provide the more chances you'll have to get an accurate answer


EMS-ESP is a project originally created by proddy with the main contributors and owners:


v2 v3


v2 v3

You can also contribute to EMS-ESP by

  • providing Pull Requests (Features, Fixes, suggestions)
  • testing new released features and report issues on your EMS equipment
  • contributing to missing Documentation

Libraries used

  • esp8266-react by @rjwats for the framework that provides the Web UI
  • uuid-* from @nomis. The console, syslog, telnet and logging is based on these libraries
  • ArduinoJson
  • AsyncMqttClient for MQTT, with modifications from @bertmelis
  • ESPAsyncWebServer and ESPAsyncTCP for the Web and TCP backends, with custom modifications for performance


This program is licensed under GPL-3.0