Metro Transparent Data Sets API
Overview
The Metro Transparent Data Sets API allows developers to create applications for the desktop, web or mobile devices that includes Metro transit data. The API is available at no charge and can be implemented in both for-profit and non-profit applications. We only ask that developers adhere to the guidelines presented in the WMATA Developer License Agreement. To make the API as flexible as possible, each method provided has two endpoints - REST and JSON. Complete documention including code samples can be found in the Documentation tab at the top of the page. To get started you will need to register and obtain an API key.
What Data is Accessible via the API?
The first seven methods to be released describe the rail transit system. Data includes the order and location of rail stations by line, train arrival predictions for each station, service alerts and Elevator/Escalator status. A comprehensive set of methods that describe Metrobus activities (including schedules, bus stop details, bus route shapes and other information) is planned for Fall 2010 release. The Transparent Data Sets API supplements other Metro data offerings. RSS Feeds, our GTFS download and other data products can be found on the Developer Resources page.
Get Started
Follow the steps below to start using the Transparent Data Sets API:
1. Register for a user account.
2. Apply for an API key.
3. Browse the documentation.
Community
Join the WMATA Transparent Data Sets API Developer Community
Application Gallery
Check out some of the applications that Transparent Data Sets Developers have released recently.
Developer News Log
May 02: 
A error in our lastest bus data (March 2013) has caused some Bus Methods to return incorrect <StopID> values. This will affect any look up to other bus data methods based on <StopID>. Our Team is working hard to identify the source of error and implement a fix.
June 21:NextBus arrival predictions are now available via the Bus Prediction method.
January 27: Bus positions service now supports lat\long and radius
December 15: Bus Stop service now supports query by radius and contains list of routes servicing a particular bus stop.
November 30: BUS DATA BECAME AVAILABLE ON DECEMBER 9! A PDF of the presentation is available here.
August 31: We have added JSONP support in response to developer requests. Check Description of Methods for details.
August 12: We have added a new method, Station Entrances, that was requested during the developer conference. Note that this method includes elevators.
August 9: Thank you to everyone who attended our developer conference. A PDF of the presentation is available here.
August 6: Metro press release announces API Developer Conference.
July 8: Metro press release announces Transparent Data Sets.
