The TeamCity API allows developers to make HTTP requests to the TeamCity server and get a response. The API is REST-based and is available as an open-source plugin. This API can be authenticated using basic HTTP authentication.
Version 4 of the API introduces an enhanced UI, historical builds, test reordering, custom builds, TeamCity IDE integration plugins improvements, Eclipse plugin improvements, .NET framework integration improvements, Ruby support, and general extensibility improvements.
TeamCity is a Java-based continuous integration and build management server from JetBrains.