MBTA API — Free Boston Transit Data (No Key, Real-Time)

TL;DR

The MBTA API v3 provides real-time and scheduled data for all Massachusetts Bay Transportation Authority services — subway (Red, Orange, Blue, Green, Mattapan), commuter rail, bus, ferry, and the Silver Line. It follows the JSON:API specification with support for filtering, pagination, includes (relationships), and spatial queries. The API is ideal for building Boston-specific transit apps, arrival prediction tools, and service alert dashboards. Basic access requires no API key.

Quick start: https://api-v3.mbta.com/routes

No API key needed — just make a request!

How to Use This API

1. List All Routes

https://api-v3.mbta.com/routes

2. Get Stops on the Red Line

https://api-v3.mbta.com/stops?filter[route]=Red

3. Predictions for Park Street

https://api-v3.mbta.com/predictions?filter[stop]=place-pktrm&sort=departure_time

4. JavaScript — Next Train Times

fetch('https://api-v3.mbta.com/predictions?filter[stop]=place-harsq&filter[route]=Red')
  .then(r => r.json())
  .then(d => {
    d.data.forEach(p => {
      const attrs = p.attributes;
      console.log(`To ${attrs.direction}: ${attrs.departure_time}`);
    });
  });

5. Python — Get Active Alerts

import requests

resp = requests.get('https://api-v3.mbta.com/alerts', params={
    'filter[activity]': 'BOARDING',
    'sort': '-updated_at'
})
alerts = resp.json()
for a in alerts['data'][:5]:
    print(a['attributes']['header'])

Try it: https://api-v3.mbta.com/routes

Try This URL Now

API Details

API URL: https://api-v3.mbta.com
Documentation: mbta.com/developers
Category: Transport
Authentication: Not Required (basic access)
Geographic Coverage: USA — Greater Boston, Massachusetts

Frequently Asked Questions

Do I need an API key for the MBTA API?: No, anonymous access works for the v3 API. Registering for a free API key (from MBTA Developer Portal) raises the rate limit from 20 to 60 requests per minute.
What transit modes are covered?: Subway/light rail (Red, Orange, Blue, Green, Mattapan), Commuter Rail (12 lines), Bus (170+ routes), Ferry (4 routes), and the Silver Line BRT.
Can I get real-time vehicle positions?: Yes, the /vehicles endpoint returns real-time GPS positions for subway trains and some buses, including latitude, longitude, speed, and bearing.
What are the stop IDs?: Stops use IDs like place-pktrm (Park Street), place-harsq (Harvard Square), place-sstat (South Station). These can be found via the /stops endpoint.
How does the JSON:API format work?: Responses use the JSON:API spec with data (primary array), included (related resources), links (pagination), and support for include parameter to eager-load relationships.
Does the API include fare information?: Yes, the /fare_products endpoint describes fare types. Real-time fare calculation is available via /fare endpoints with origin/destination parameters.

What You Can Build

Boston subway arrival time display for stations
Commuter rail schedule app with delay alerts
Multi-modal trip planner combining bus and T
Service disruption dashboard with real-time alerts
Commute cost calculator with fare information