Getting started

Welcome! TransitMatters Labs is run entirely by volunteers. Here's how to go from zero to your first merged PR.

1. Get connected

• Fill out the volunteer form if you haven't already.
• Join the Labs Slack channel. It's the place to ask questions, find a project and get AWS access if you need it.

2. Learn the shape of things

Read the architecture overview. It takes five minutes. The key idea: most projects read from one shared data pipeline that ends in the Data Dashboard API.

3. Pick a project

If you like…	Try
Frontend, charts, React	Data Dashboard
Something small to learn the ropes	Pride Bus or Shutdown Tracker
Maps and live data	New Train Tracker
Python and data wrangling	data-ingestion or mbta-performance

Browse each repo's Issues for something to pick up, or ask in Slack.

4. Set up your machine

You'll need:

• Git and a GitHub account
• Node: use the version in the repo's .nvmrc (nvm install && nvm use)
• Python + uv. A few older repos use Poetry; the README will say.
• A free MBTA V3 API key for apps that call the MBTA directly

You don't need AWS access to start

Most apps run locally against public data. For the Data Dashboard, export TM_BACKEND_SOURCE=prod points your local copy at the production API.

Most full-stack repos start with:

npm install
npm start   # runs the frontend and the Python backend together

5. Make a change

1. Create a branch and open a pull request.
2. CI runs lint and tests. Run npm run lint (or uv run ruff check .) locally first.
3. A maintainer reviews it.
4. Merging to main deploys to production. That's why reviews matter.

Help

Stuck? Ask in Slack. Every repo also has a CODEOWNERS file listing who maintains it.