Freematics Builder is a fully self-contained utility which integrates all the toolchains, Arduino cores and libraries for easily uploading Arduino sketches or pre-compiled binaries to one of AVR based Arduino boards or ESP8266 and ESP32 variants. A simple code viewer and serial monitor are also integrated.

Freematics Builder supports custom configuration for compiling a sketch, with a UI created from a config file (example). Extra compiler options will be generated for compiling. This makes it easy to configure a sketch with some optional features or parameters, without changing code manually.


  • Compiling Arduino sketch for AVR, ESP32 and ESP8266 targets
  • Uploading binary to Arduino boards or Freematics products
  • Built-in serial monitor
  • SPIFFS image creation and uploading
  • Customizable building configuration UI




Version 1.1.3 (15 SEP 2019)

  • Updated ESP32 Arduino core
  • Updated esptool
  • Integrated ESP-MDF (WiFi mesh support for ESP32)
  • Fixed occasional ESP32 reset issue
  • Changed ESP32 default upload baud rate to 921600bps

Version 1.1.1 (30 MAY 2019)

  • Updated ESP32 SDK
  • Updated esptool
  • CPU frequency configurable for ESP32

Version 1.1.0 (15 APR 2019)

  • Updated ESP32 Arduino core
  • Added auto-reset option
  • Improved UI

Version 1.0.12 (24 JUL 2018)

  • Updated ESP32 Arduino core
  • Added image verification for ESP32
  • Allowing uploading pre-built file system image

Version 1.0.11 (22 MAY 2018)

  • Fixed partition setting for ESP32 with 16MB flash so SPIFFS partition can reach the end of flash

Version 1.0.10 (8 APR 2018)

  • SPIFFS image creation and uploading for ESP8266 and ESP32
  • Updated ESP32 Arduino core

Version 1.0.9 (29 MAR 2018)

  • SPIFFS image creation

Version 1.0.8 (16 MAR 2018)

  • Updated ESP-IDF SDK and ESP32 Arduino core (using 240Mhz clock)
  • Updated ESP8266 Arduino core
  • Updated ESPtool

Version 1.0.7 (16 JAN 2018)

  • Fixed a serial monitor issue

Version 1.0.6 (28 NOV 2017)

  • Added ESP8266 target

Version 1.0.5 (6 NOV 2017)

  • Updated ESP32 support for Arduino IDE (80Mhz clock)
  • Cleaned up ESP32 boards type list in Arduino IDE

Version 1.0.4 (22 OCT 2017)

  • Updated ESP32 SDK and Arduino core
  • Changed default ESP32 clock to 80Mhz (lower power consumption)
  • Purging build folder during installation to ensure a clean first-time build
  • Fixed the bug that source code can’t reside in folder with white space in name
  • Fixed a GUI issue
  • Updated Electron runtime

Version 1.0.3 (2 OCT 2017)

  • Updated ESP32 SDK and Arduino core
  • Changed ESP32 default upload baud rate to 115200bps
  • Fixed several GUI issues

Version 1.0.2 (17 JUL 2017)

  • Added uploading baud rate option
  • Adjusted library path searching range in accordance to Arduino IDE

Version 1.0.1 (3 JUL 2017)

  • Added optional rebuild for library and core files