V3 API

To start your Phoenix app:

1. Install required Erlang and Elixir versions:
   1. Install asdf package manager
   2. Run asdf plugin-add erlang to add Erlang plugin
   3. Run asdf plugin-add elixir to add Elixir plugin
   4. Optionally install plugins for load testing:
      • Run asdf plugin-add python to add Python plugin
      • Run asdf plugin-add poetry to add Poetry plugin
   5. Run asdf install to install plugin versions specified in .tool-versions file
2. Install dependencies with mix deps.get
3. Setup apps/api_accounts following directions in apps/api_accounts/README.md (on GitHub or ExDoc)
4. Start Phoenix endpoint with mix phx.server

Now you can visit localhost:4000 from your browser.

Tests

To run the tests, first install and setup Colima, Docker, and docker-compose:

brew install docker docker-compose colima
colima start
mkdir -p ${DOCKER_CONFIG:-"~/.docker"}/cli-plugins
ln -sfn /opt/homebrew/opt/docker-compose/bin/docker-compose ${DOCKER_CONFIG:-"~/.docker"}/cli-plugins/docker-compose

Then, start the Compose configuration in a separate window or tab and run the tests:

1. docker compose up
2. mix test

Environment Variables

In addition to the Elixir config files, the V3 API allows runtime configuration through a collection of environment variables.

Environment Variable	Default	Description
LOG_LEVEL	info	Log level to use. Can be changed to debug.
PORT	4000	The HTTP port the server will listen on.
HOST	undefined	The public-facing hostname for the server, used to generate URLs.
MBTA_GTFS_URL	https://cdn.mbta.com/MBTA_GTFS.zip	URL for the GTFS .zip file.
ALERT_URL	https://cdn.mbta.com/realtime/Alerts_enhanced.json	URL for the Alerts. Can be either a JSON or Protobuf file.
MBTA_TRIP_SOURCE	https://cdn.mbta.com/realtime/TripUpdates_enhanced.json	URL for the TripUpdates. Can be either a JSON or Protobuf file.
MBTA_VEHICLE_SOURCE	https://cdn.mbta.com/realtime/VehiclePositions_enhanced.json	URL for the VehiclePositions. Can be either a JSON or Protobuf file.
FETCH_FILETAP_S3_BUCKET	undefined	S3 bucket to which we write files we fetched.

Documentation

Swagger

Swagger documentation for the Api is generated automatically.

1. mix phoenix.server
2. open http://localhost:4000/docs/swagger

Want to contribute?

Thank you for wanting to contribute! We use the built in mix format for code formatting, and ExUnit for testing.

# Format all code
$ mix format

# Run all unit tests
$ mix test

# Run the integration tests
$ mix test --exclude test --include integration

Learn more

• Docs: https://www.mbta.com/developers/v3-api
• Mailing list: https://groups.google.com/forum/#!forum/massdotdevelopers

About us

The MBTA Customer Technology team is working to transform how people get around the Boston area. We’re a small but mighty team of designers, engineers and content specialists charged with bringing novel ideas, modern standards and a user-centered approach to technology on the T. As the MBTA works to reinvent itself, we have a rare opportunity to shape the future of transportation for Boston and communities all around Eastern Massachusetts, as well as blaze a trail for other transit agencies around the country.

We’re always looking for people to join the team who are passionate about improving the daily transportation experience for our 400 million annual riders. Does this sound like you? Check out our open positions at https://jobs.lever.co/mbta/.