Custom Embedded Board

PlatformIO has pre-built settings for the most popular embedded boards. This list is available:

Nevertheless, PlatformIO allows one to create own board or override existing board’s settings. All data is declared using JSON-style via associative array (name/value pairs).

JSON Structure

The key fields:

  "build": {
    "extra_flags": "-DHELLO_PLATFORMIO",
    "f_cpu": "16000000L",
    "hwids": [
    "mcu": "%MCU_TYPE_HERE%"
  "name": "My Test Board",
  "upload": {
    "maximum_ram_size": 2048,
    "maximum_size": 32256
  "url": "",
  "vendor": "MyCompany"


  1. Create boards directory in core_dir if it doesn’t exist.
  2. Create myboard.json file in this boards directory.
  3. Search available boards via platformio boards command. You should see myboard board.

Now, you can use myboard for the board option in “platformio.ini” (Project Configuration File).


You can have custom boards per project. In this case, please put your board’s JSON files to boards_dir.


Please take a look at the source code of PlatformIO Development Platforms and navigate to boards folder of the repository.