Build artifacts are files produced by a build and stored on the server. Typically these include distribution packages, WAR files, reports, log files, etc. When creating a build configuration you specify artifacts of your build at the General Settings page.

Upon build finish, TeamCity searches for artifacts in the build's checkout directory according to the specified artifact patterns. Matching files are then uploaded ("published") to the TeamCity server, where they become available for download through the web UI or can be used in other builds using artifact dependencies.

To download artifacts of a build use Artifacts column of the build entry on those TeamCity pages that list the builds, or you can find them at the Artifacts tab of the build results page. You can automate artifacts downloading as described in the Patterns For Accessing Build Artifacts section.

TeamCity stores artifacts on disk in a directory structure that can be accessed directly (for example, by configuring the Operating System to share the directory over the network). The artifacts are stored under <TeamCity data directory>/system/artifacts folder. Storage format is described in the TeamCity Data Directory section. The artifacts are stored on the server "as is" without additional compression, etc. TeamCity computer's administrator can delete artifacts directly form the disk. In this case, build's artifacts will no longer be available.

All artifacts stay on the server and are available for download until they are cleaned up.

Build artifacts can also be uploaded to the server while the build is still running. To instruct TeamCity to upload the artifacts, build script should be modified to send service messages

Hidden Artifacts

In addition to user-defined artifacts, TeamCity also generates and publishes some artifacts for internal purposes. These are called hidden artifacts.
For example, for Maven builds, TeamCity creates maven-build-info.xml file that contains Maven-specific data collected during the build. Content of the file is then used to visualize the Maven data on the Maven Build Info tab in the build results.

not yet hidden:, teamcity-info.xml

See also:

Concepts: Dependent Build
Administrator's Guide: Configuring General Settings | Configuring Dependencies | Patterns For Accessing Build Artifacts