Contributing to Matter (formerly Project CHIP)

Want to contribute? Great! First, read this page (including the small print at the end). By submitting a pull request, you represent that you have the right to license your contribution to the Connectivity Standards Alliance and the community, and agree by submitting the patch that your contributions are licensed under the Apache 2.0 license. Before submitting the pull request, please make sure you have tested your changes and that they follow the project guidelines for contributing code.

Contributing as an Open Source Contributor

As an open source contributor you can report bugs and request features in the Issue Tracker, as well as contribute bug fixes and features that do not impact Matter specification as a pull request. For example: ports of Matter to add APIs to alternative programming languages (e.g. Java, JS), hardware ports, or an optimized implementation of existing functionality. For features that impact the specification, please join Matter work group within the Connectivity Standards Alliance. The requirements to become an open source contributor of the Matter Repository are:

Contributing as a Connectivity Standards Alliance Matter Working Group Member

As a participant of the Connectivity Standards Alliance Matter Working Group, you can attend Working Group meetings, propose changes to the Matter specification, and contribute code for approved updates to the specification. The requirements to become a member of the Matter Repository are:

  • Must be a Participant member or higher of the Connectivity Standards Alliance
  • Must be a Matter Working Group member
  • Have signed the Alliance Matter Working Group CLA
  • Have approval from your company's official approver


If you find a bug in the source code, you can help us by submitting a GitHub Issue. The best bug reports provide a detailed description of the issue and step-by-step instructions for predictably reproducing the issue. Even better, you can submit a Pull Request with a fix.

New Features

You can request a new feature by submitting a GitHub Issue. If you would like to implement a new feature, please consider the scope of the new feature:

  • Large feature: first submit a GitHub Issue and communicate your proposal so that the community can review and provide feedback. Getting early feedback will help ensure your implementation work is accepted by the community. This will also allow us to better coordinate our efforts and minimize duplicated effort.
  • Small feature: can be implemented and directly submitted as a Pull Request.

Contributing Code

Matter follows the “Fork-and-Pull” model for accepting contributions.

Initial Setup

Setup your GitHub fork and continuous-integration services:

  1. Fork the Matter repository by clicking “Fork” on the web UI.

  2. All contributions must pass all checks and reviews to be accepted.

Setup your local development environment:

# Clone your fork
git clone<username>/connectedhomeip.git

# Configure upstream alias
git remote add upstream

Submitting a Pull Request


For each new feature, create a working branch:

# Create a working branch for your new feature
git branch --track <branch-name> origin/master

# Checkout the branch
git checkout <branch-name>

Create Commits

# Add each modified file you'd like to include in the commit
git add <file1> <file2>

# Create a commit
git commit

This will open up a text editor where you can craft your commit message.

Upstream Sync and Clean Up

Prior to submitting your pull request, you might want to do a few things to clean up your branch and make it as simple as possible for the original repository's maintainer to test, accept, and merge your work.

If any commits have been made to the upstream master branch, you should rebase your development branch so that merging it will be a simple fast-forward that won't require any conflict resolution work.

# Fetch upstream master and merge with your repository's master branch
git checkout master
git pull upstream master

# If there were any new commits, rebase your development branch
git checkout <branch-name>
git rebase master

Now, it may be desirable to squash some of your smaller commits down into a small number of larger more cohesive commits. You can do this with an interactive rebase:

# Rebase all commits on your development branch
git checkout <branch-name>
git rebase -i master

This will open up a text editor where you can specify which commits to squash.

Push and Test

# Checkout your branch
git checkout <branch-name>

# Push to your GitHub fork:
git push origin <branch-name>

This will trigger the continuous-integration checks. You can view the results in the respective services. Note that the integration checks will report failures on occasion.

Review Requirements

Documentation Best Practices

Matter uses Doxygen to markup (or markdown) all C, C++, Objective C, Objective C++, Perl, Python, and Java code. Read our Doxygen Best Practices, Conventions, and Style

Submit Pull Request

Once you've validated the CI results, go to the page for your fork on GitHub, select your development branch, and click the pull request button. If you need to make any adjustments to your pull request, just push the updates to GitHub. Your pull request will automatically track the changes on your development branch and update.

Merge Requirements

  • Github Workflows pass
  • Builds pass
  • Tests pass
  • Linting passes
  • Code style passes

When can I merge? After these have been satisfied, a reviewer will merge the PR into master


Documentation undergoes the same review process as code See the Documentation Style Guide for more information on how to author and format documentation for contribution.

Merge Processes

Merges require at least 3 approvals from unique require-reviewers lists, and all CI tests passing.

Shorter Reviews

Development Lead & Vice Leads can merge a change with fewer then the required approvals have been submitted.

A separate “fast track” label will be created that will only require a single checkbox to be set, this label shall only be set by the Development Lead, and/or Vice Lead (unless they’re both unavailable, in which case a replacement can be temporarily appointed)

“Day” here means “business day” (i.e. PRs on friday do not get fast-tracked faster).

Fast track types

Trivial changes

Small changes or changes that do not affect the main functionality of the code can be fast tracked immediately. Examples:

  • Adding/removing documentation (.md files)
  • Adding tests (may include small reorganization/method adding/changes to enable testability):
    • certification tests
    • stability tests
    • integration tests
    • functional tests
    • Test scripts
    • Additional tests following a pattern (e.g. YAML tests)
  • Adding/updating/fixing tooling to aid in development
  • Re-running code generation
  • Code readability refactors:
    • renaming enum/classes/structure members
    • moving constant header location
    • Obviously trivial build rule changes (e.g. adding missing files to build rules)
    • Changing comments
    • Adding/removing includes (include what you need and only what you need rules)
  • Pulling new third-party repo files
  • Platform vendors/maintainers adding platform features/logic/bug fixes to their own platforms
  • Most changes to existing docker files (pulling new versions, reorganizing)
  • Most changes to new dockerfile version in workflows

Fast track changes

Larger functionality changes are allowed to be fast tracked with these requirements/restrictions:

  • Require at least 1 day to have passed since the creation of the PR
  • Require at least 1 checkmark from someone familiar with the code or problem space
    • This requirement shall be dropped after a PR is 3 days old with stale or no feedback.
  • Code is sufficiently covered by automated tests (or impossible to automatically test with a very solid reason for this - e.g. changes to BLE parameters cannot be automatically tested, but should have been manually verified)

Fast tracking these changes will involve resolving any obviously ‘resolved’ comments (judgment call here: were they replied to or addressed) and merging the change.

Any “request for changes” marker will always be respected unless obviously resolved (i.e. author marked “requesting changes because of X and X was done in the PR”)

  • This requirement shall be dropped after a PR is 3 days old with stale or no feedback.