# Build Configurations

New in version 4.0.0.

There are 2 types (build_type) of build configuration in PlatformIO:

`release`

  Default configuration. A “release” configuration of your firmware/program does not contain symbolic debug information and is optimized for the firmware size or speed (depending on Development Platforms)

`debug`

  A “debug” configuration of your firmware/program is compiled with full symbolic debug information and no optimization. Optimization complicates debugging, because the relationship between source code and generated instructions is more complex.

Note

If you need to control build flags that are specific for debug configuration please refer to debug_build_flags.

If you need to build a project in `debug` configuration, please use one of these options:

- Add build_type with `debug` value to “platformio.ini” (Project Configuration File)

- Use target `debug` for the `platformio run --target` command.

Note

PIO Unified Debugger automatically switches to `debug` configuration when you do project debugging from PlatformIO IDE or use the platformio debug command.

To avoid having PIO Unified Debugger rebuild the project, please create a separate build environment that defines `build_type = debug`. See the example below where the `mydebug` build environment will be used automatically by PIO Unified Debugger:

    [env]
    platform = ...
    board = ...
    framework = ...
    ... other common configuration

    [env:myrelease]
    some_extra_options = ...

    [env:mydebug]
    build_type = debug
    some_extra_options = ...

Please note that you can set a default build environment per a project using the default_envs option in Section [platformio].