The MAR Web Services are a series of APIs which primarily call DC Government’s Master Address Repository (MAR). These operations return a wealth of information about locations in Washington, DC. These locations include addresses, blocks, intersection, place names. We offer XML based returns and JSON. These APIs are available to all users. There are 68 operations. The APIs are behind a large number of applications both inside and outside DC Government. These APIs are free to use both inside and outside of government. By using the MAR Web Services, users can take advantage of DC's authoritative data sources including the best available source of addressing and street network. The data behind the MAR Web Services is updated on a regular basis.