Python Matter Server is an officially certified Software Component that provides Matter controller support. It serves as the foundation for Matter support in Home Assistant and other projects. The server implements a Matter Controller over WebSockets using the official Matter SDK.

Always reference these instructions first and fallback to search or bash commands only when you encounter unexpected information that does not match the info here.

• CRITICAL: Matter Server requires Linux or macOS with specific IPv6 networking configuration. Windows/WSL is NOT supported.
• Set up the complete development environment:

  scripts/setup.sh

  • Creates Python virtual environment in .venv/
  • Installs Python dependencies including Matter SDK components
  • Installs pre-commit hooks for code quality
  • TIMING: Typically takes 3-5 minutes. NEVER CANCEL - wait up to 10 minutes for completion.
  • NETWORK ISSUE: If pip install fails with timeout errors (common with Matter SDK dependencies), this is due to network limitations, not code issues.

• Always run the bootstrapping steps first before any Python development
• Start the Matter server:

  # Basic server (info log level)
  python -m matter_server.server
  
  # Debug mode
  python -m matter_server.server --log-level debug
  
  # SDK debug mode
  python -m matter_server.server --log-level-sdk progress

• Create /data directory with proper permissions if it doesn't exist
• Server runs on port 5580 by default (WebSocket endpoint)
• Alternative entry point: python main.py

• Dashboard setup (requires Python dependencies to be available):

  cd dashboard
  script/setup

  • Runs npm install (~15 seconds)
  • Generates descriptions file from Python source
  • TIMING: ~30 seconds total. NEVER CANCEL - set timeout to 2+ minutes.

• Development server:

  cd dashboard
  script/develop

  • Starts TypeScript compiler in watch mode
  • Starts development server on http://localhost:5010
  • Live reload for development changes
  • TIMING: Starts in ~5 seconds

• Production build:

  cd dashboard
  script/build

  • Builds optimized TypeScript/JavaScript bundle
  • Copies build to matter_server/dashboard/ directory
  • TIMING: ~10 seconds. NEVER CANCEL - set timeout to 2+ minutes.

• Run complete test suite:

  scripts/run-in-env.sh pytest --durations 10 --cov-report term-missing --cov=matter_server --cov-report=xml tests/

  • TIMING: Typically 2-3 minutes. NEVER CANCEL - set timeout to 10+ minutes.

• Pre-commit validation (REQUIRED before commits):

  SKIP=no-commit-to-branch pre-commit run --all-files

  • Runs ruff (linting + formatting), pylint, mypy, codespell, and other checks
  • TIMING: 1-2 minutes for all files. NEVER CANCEL - set timeout to 5+ minutes.

• Individual linting tools:

  scripts/run-in-env.sh ruff check --fix
  scripts/run-in-env.sh ruff format
  scripts/run-in-env.sh pylint matter_server/ tests/
  scripts/run-in-env.sh mypy

ALWAYS manually validate changes using complete end-to-end scenarios:

1. Start the server: python -m matter_server.server --log-level debug
2. Verify WebSocket endpoint responds (server starts without errors)
3. Check dashboard is accessible if built: verify matter_server/dashboard/ contains files
4. Test example client: python scripts/example.py (requires dependencies)

1. Build dashboard: cd dashboard && script/build
2. Verify build artifacts: check matter_server/dashboard/js/ contains compiled JavaScript
3. Start development server: cd dashboard && script/develop
4. Access http://localhost:5010 and verify dashboard loads
5. Test WebSocket connection input (should prompt for server URL)

CRITICAL: Always run before pushing changes or CI will fail:

SKIP=no-commit-to-branch pre-commit run --all-files

matter_server/           # Main Python package
├── client/             # Matter client library
├── server/             # Matter server implementation
├── common/             # Shared utilities
└── dashboard/          # Built web dashboard (auto-generated)

dashboard/              # Dashboard source code (TypeScript/Lit)
├── src/               # TypeScript source files
├── script/            # Build and development scripts
└── public/            # Static assets

scripts/               # Development utilities
├── setup.sh          # Main environment setup
├── example.py        # Server/client example
└── generate_descriptions.py  # Generates dashboard type definitions

tests/                 # Test suite (pytest-based)
docs/                  # Documentation
├── os_requirements.md # Operating system setup requirements
├── docker.md         # Docker deployment guide
└── websockets_api.md  # WebSocket API documentation

• pyproject.toml - Python packaging and tool configuration
• main.py - Alternative server entry point
• .pre-commit-config.yaml - Code quality hooks configuration
• DEVELOPMENT.md - Detailed development setup guide

SYMPTOM: pip install fails with ReadTimeoutError from PyPI CAUSE: Matter SDK dependencies are large and can timeout on slow connections SOLUTION:

• Retry setup: scripts/setup.sh
• Use pip install --timeout 300 for extended timeout
• Document as known issue if persistent

SYMPTOM: Matter devices not discoverable or connection failures REFERENCE: See docs/os_requirements.md for complete networking requirements KEY REQUIREMENTS:

• IPv6 support enabled on host interface
• No multicast filtering on network equipment
• Proper ICMPv6 Router Advertisement processing
• For Thread devices: specific kernel options and sysctl settings

SYMPTOM: Git commits rejected due to formatting/linting issues SOLUTION:

SKIP=no-commit-to-branch pre-commit run --all-files
scripts/run-in-env.sh ruff format  # Fix formatting
scripts/run-in-env.sh ruff check --fix  # Fix linting issues

SYMPTOM: script/setup fails with "No module named 'chip'" CAUSE: Python Matter SDK dependencies not installed SOLUTION: Run scripts/setup.sh first to install Python dependencies

• Always activate virtual environment: source .venv/bin/activate
• Use scripts/run-in-env.sh for consistent tool execution across environments
• Dashboard development can proceed independently once built once
• Server requires /data directory for persistent storage
• Matter protocol requires specific OS and network configuration (see docs/os_requirements.md)
• Example usage patterns available in scripts/example.py
• WebSocket API documentation in docs/websockets_api.md

The project uses GitHub Actions (.github/workflows/test.yml):

• Linting: pre-commit hooks on Python 3.12
• Testing: pytest on Python 3.12 and 3.13
• Always ensure pre-commit passes locally before pushing to avoid CI failures

This project implements both server and client components:

• Server: Runs Matter Controller with WebSocket API
• Client: Python library for consuming the WebSocket API (used by Home Assistant)
• Dashboard: Web-based debugging and testing interface
• Architecture: Allows multiple consumers to connect to same Matter fabric
• Deployment: Available as Home Assistant add-on, Docker container, or standalone

The separation enables scenarios where the Matter fabric continues running while consumers (like Home Assistant) restart or disconnect.

CRITICAL: All code changes MUST pass linting checks before submitting PRs. The CI will fail if linting issues are present.

Always run these commands before committing and pushing changes:

# Run all pre-commit checks (REQUIRED)
SKIP=no-commit-to-branch pre-commit run --all-files

# Individual linting tools for troubleshooting
scripts/run-in-env.sh ruff check --fix      # Fix linting issues
scripts/run-in-env.sh ruff format           # Fix formatting
scripts/run-in-env.sh pylint matter_server/ tests/  # Check code quality
scripts/run-in-env.sh mypy                  # Check type annotations

The project uses multiple linting tools enforced via pre-commit hooks:

• ruff: Fast Python linter and formatter (replaces flake8, isort, etc.)
• pylint: Static code analysis for code quality
• mypy: Static type checking
• codespell: Spell checking for code and documentation
• File format checks: JSON, TOML validation, trailing whitespace, end-of-file fixers

Trailing Whitespace: Remove all trailing spaces from lines Missing Newline: Ensure files end with a single newline character Import Order: Use ruff format to fix import sorting Type Annotations: Add type hints where mypy reports missing annotations Spelling: Use codespell to check for typos in code and comments

Most linting issues can be automatically fixed:

scripts/run-in-env.sh ruff check --fix    # Auto-fix many linting issues
scripts/run-in-env.sh ruff format         # Auto-format code

Always verify changes after auto-fixing and run the full pre-commit suite before submitting.