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 6.0 of the API introduces improved upgrade procedures, new build runners, maven integration, JetBrains dotCover integration, web interface improvements, build priorities, better handling of "failed to start" builds, improvements in IDE plugins, VCS integration improvements, and TeamCity usage statistics.
TeamCity is a Java-based continuous integration and build management server from JetBrains.