Dependency Management

Modern software projects rarely work in isolation. In most cases, a project relies on reusable functionality in the form of libraries or is broken up into individual components to compose a modularized system. Dependency management is a technique for declaring, resolving, and using dependencies required by the project in an automated fashion.

PlatformIO is the missing solution in the embedded system industry which has built-in support for dependency management and lives up to the task of fulfilling typical scenarios encountered in modern software projects.

Library Registry

PlatformIO Registry contains a rich set of popular libraries with examples and instructions on how to add them to your project. Libraries in PlatformIO are isolated between projects and project environments. This helps you to avoid conflicts or break existing projects when you update libraries to the newest versions.

If you prefer using PlatformIO Core (CLI) instead of web browsing, the pio pkg search command allows you to search for libraries matching the search query.

Library sources

PlatformIO supports different library sources which you can use for declaring dependencies. The most popular are:

  • Versioned libraries from PlatformIO Registry

  • VCS repositories (Git, Hg, SVN)

  • Remote or local library as a TAR or ZIP archive

  • Local library as a source folder.

Dependency specifications

Please check Package Specifications for the available options.

Declaring dependencies

“platformio.ini” (Project Configuration File) and the lib_deps is the only place for declaring project dependencies. There are 2 sections where dependencies can be declared:

  1. Section [env] - declare common dependencies for all environments

  2. Working [env:NAME] - declare specific dependencies for the working environment.

Please take a look at the example below. The dep_1 and dep_2 dependencies are common to the release and debug working environments, whereas the dep_3 is a specific only for the debug working environment. The [env:debug] section overrides common lib_deps option, and the ${env.lib_deps} (Interpolation of Values technic) is used to merge the common and custom dependencies.

; Common dependencies declared in the common "[env]" section
platform = ...
board = ...
framework = ...
lib_deps =

build_flags = -D RELEASE=1

; Specific dependencies that extend the common dependencies
lib_deps =


If some libraries are not visible in PlatformIO IDE and Code Completion or Code Linting does not work properly, please perform

  • VSCode: “Menu: View > Command Palette... > PlatformIO: Rebuild C/C++ Project Index”

Declaring practices

Good practice

lib_deps =
  ; Depend on the latest 6.x stable version of ArduinoJson.
  ; The minimum required version is 6.19.4.
  ; New functionality (backward-compatible) and bug-fixed are allowed
  bblanchon/ArduinoJson @ ^6.19.4

  ; Depend on the exact 1.1.1 version
  ; No new functionality (backward-compatible) or bug fixes.
  ; Recommended for safety-critical projects
  me-no-dev/AsyncTCP @ 1.1.1

  ; Depend on the particular tag (v2.13) of a Git repository

Bad practice



lib_deps =
  ; Omit library package owner (<owner>/<name>) and depend on the library by name.
  ; Lead to the conflicts when there are multiple libraries with the same name

  ; Depend on ANY/Latest version of the development platform
  ; allowing breaking changes

  ; Depend on the development branch of the Git repository,
  ; allow breaking changes, and untested commits

Installing dependencies

PlatformIO automatically resolves and installs project dependencies when you build, debug, or test a project. If you want to install project dependencies manually, please use PlatformIO Core (CLI) and the pio pkg install command.

Updating dependencies

PlatformIO does not update project dependencies automatically. You need to use PlatformIO Core (CLI) and the pio pkg update command to update all project dependencies or for the specified environment. It is also possible to update the specified dependency.

We recommend using the pio pkg outdated command, checking available updates, and avoiding versions that introduce breaking changes.