head to head · open source
OpenMQTTGateway vs EMS-ESP32
OpenMQTTGateway has 4,094 GitHub stars, 906 forks, 48 open issues and last shipped today. EMS-ESP32 has 1,010 stars, 152 forks, 15 open issues and last shipped 2 days ago. OpenMQTTGateway leads on adoption by 305% (4,094 vs 1,010 stars). OpenMQTTGateway is written in C++ under GPL-3.0; EMS-ESP32 is written in C++ under LGPL-3.0. OpenMQTTGateway has attracted 22% as many forks as stars, EMS-ESP32 15%. OpenMQTTGateway was the more recently maintained of the two, and both are self-hostable with no licence fee. The two share 3 topic tags (esp32, home-assistant, home-automation), so they are genuine substitutes rather than adjacent tools.
Two open source projects, one decision. Both are free and self-hostable — the differences are community size, license terms, language stack and release pace.
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Side by side
| OpenMQTTGateway | EMS-ESP32 | |
|---|---|---|
| GitHub stars | ★ 4.1K | ★ 1.0K |
| License | GPL-3.0 | LGPL-3.0 |
| Written in | C++ | C++ |
| Last push | 2026-09-20 | 2026-09-18 |
| Forks | ⑂ 906 | ⑂ 152 |
| Self-hosting | Yes | Yes |
| Data ownership | Your server | Your server |
pick OpenMQTTGateway if
- You weight community size — 4.1K stars and counting
- You want the GPL-3.0 license terms
- Your stack matches C++
- You value the larger contributor base for long-term maintenance
pick EMS-ESP32 if
- You want the EMS-ESP32 feature set and don't need the biggest community
- You prefer the LGPL-3.0 license terms
- Your stack matches C++
- You evaluated both and EMS-ESP32 fits your workflow better
About OpenMQTTGateway
OpenMQTTGateway is an open source C++ gateway firmware for ESP8266 and ESP32 boards that connects local radio and sensor protocols to MQTT. It lives in the home automation ecosystem and is associated with Home Assistant, OpenHAB, NodeRed, and AWS IOT. The project aims to unify various technologies and protocols into a single firmware, reducing the need for multiple physical bridges.
read the full OpenMQTTGateway overview →
About EMS-ESP32
EMS ESP32 is an open source C++ firmware for the Espressif ESP32 microcontroller that reads and controls EMS and Heatronic compatible equipment such as boilers, thermostats, solar modules and heat pumps, built for technically confident home automation users who own Bosch, Buderus, Nefit, Junkers, Worcester, Sieger, elm.leblanc or iVT heating hardware.
read the full EMS-ESP32 overview →
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Frequently asked questions
Is OpenMQTTGateway or EMS-ESP32 more popular?
OpenMQTTGateway has 4,094 GitHub stars and EMS-ESP32 has 1,010. OpenMQTTGateway has the larger community by that measure.
Are OpenMQTTGateway and EMS-ESP32 free?
Both are open source. OpenMQTTGateway is licensed under GPL-3.0 and EMS-ESP32 under LGPL-3.0. Neither carries a licence fee.
What is the difference between OpenMQTTGateway and EMS-ESP32?
OpenMQTTGateway is written in C++ and EMS-ESP32 in C++. The practical differences are community size, licence terms, language stack and release cadence — all compared in the table above.
Which should I choose, OpenMQTTGateway or EMS-ESP32?
Choose OpenMQTTGateway if you want the larger community (4,094 stars) or its GPL-3.0 licence terms. Choose EMS-ESP32 if its feature set, stack or LGPL-3.0 licence fits better. Both are self-hostable.