Transport for Atlanta, US — Free MARTA Transit API (No Key)

TL;DR

MARTA (Metropolitan Atlanta Rapid Transit Authority) provides a free API for real-time transit data across the Atlanta metro area. Get bus and rail arrival predictions, route configurations, stop locations, fare information, and service alerts. Covers MARTA's rail network (4 lines, 38 stations) and extensive bus network (91 routes). No API key required.

Quick start: http://www.itsmarta.com/app-developer-resources.aspx

No API key needed — free Atlanta transit data!

How to Use This API

1. Get Rail Arrival Predictions

Real-time train arrival times for a specific station (Five Points):

http://developer.itsmarta.com/rail-pred/DeveloperRailPredictions.php?stationCode=FP

2. Get All Bus Predictions

http://developer.itsmarta.com/bus-pred/BusPredictions.php

3. List All Rail Stations

http://developer.itsmarta.com/rail-stations/StationList.php

4. JavaScript — Train Times at a Station

const station = 'FP'; // Five Points
fetch(`http://developer.itsmarta.com/rail-pred/DeveloperRailPredictions.php?stationCode=${station}`)
  .then(r => r.json())
  .then(trains => {
    trains.forEach(t => {
      console.log(`${t.LINE} to ${t.DIRECTION} — ${t.WAITING_TIME}`);
      console.log(`  Platform: ${t.PLATFORM}, Event: ${t.EVENT_TYPE}`);
    });
  });

5. Python — Bus Route Stops

import requests

routes = requests.get(
    'http://developer.itsmarta.com/bus-pred/BusPredictions.php'
).json()

print(f"Active buses: {len(routes)}")
for bus in routes[:10]:
    print(f"Route {bus['ROUTE']}: {bus['DIRECTION']}")
    print(f"  Next stop: {bus['STOP_NAME']} in {bus['WAITING_TIME']}")

Five Points arrivals: http://developer.itsmarta.com/rail-pred/DeveloperRailPredictions.php?stationCode=FP

Try This URL Now

Frequently Asked Questions

What station codes are available for rail predictions?: Common codes: FP (Five Points), AS (Airport), NS (North Springs), DO (Doraville), IN (Indian Creek), HE (Heidelberg). Full list available from the StationList endpoint.
What data does the rail prediction endpoint return?: Each prediction includes LINE (RED, GOLD, BLUE, GREEN), DIRECTION, WAITING_TIME (minutes/ARRIVING), STATION, PLATFORM, and EVENT_TYPE.
Does the API cover both bus and rail?: Yes — bus predictions, rail predictions, station lists, and service alerts are all available through separate endpoints documented in the developer resources.
How often is real-time data updated?: Predictions update every 30-60 seconds. Train positions are tracked via the system's signaling network. Bus predictions use GPS tracking from onboard units.
Are there any restrictions on API usage?: MARTA's API is free and open to developers. Attribution to MARTA is appreciated. No formal rate limits are published, but reasonable usage is expected.
Does it support GTFS schedule data?: MARTA also publishes GTFS schedule data for offline trip planning. The real-time API described here provides live predictions on top of those schedules.

API Details

API URL: http://developer.itsmarta.com/
Documentation: itsmarta.com/app-developer-resources
Category: Transportation
Authentication: Not Required
Geographic Coverage: Atlanta, Georgia, USA metropolitan area

What You Can Build

Atlanta transit app showing real-time train and bus arrivals
Digital station sign with next train departing times
Commuter dashboard combining rail and bus ETAs for a route
MARTA service alert monitor for delay notifications
Station departure board for office lobbies near rail stations