Identifier
An ID is an identifier given by users to TeamCity objects (Project, build configuration, build configuration template and VCS root, etc.). The ID is unique within all the objects of the same type on the entire server; note that build configurations and templates share the same ID space.
IDs can contain only alpha-numeric characters and underscore ("_") and should start with a Latin letter.
Using IDs
IDs are used:
in URLs of the web interface (including Syndication Feed, NuGet feed)
in Predefined Build Parameters and Predefined Build Parameters parameter references
in REST API and build scripts used to automate actions with TeamCity (e.g. download artifacts via direct URLs or Ivy)
in the configuration files storing settings of projects and build configurations under TeamCity Data Directory
in file and directory names under TeamCity Data Directory (e.g. build artifacts storage)
Assigning IDs
By default, TeamCity automatically suggests an ID for an object by converting its name to match the ID requirements and prefixing that with the ID of the parent project. The ID can be modified manually.
It is recommended to leave the automatically generated IDs as is unless there are special considerations to modify them.
If you consider moving projects between several TeamCity server installations, it is a good practice to make sure that all the IDs are globally unique.
To reset the IDs to match the default scheme for all projects, VCS roots, build configurations and templates, use the Bulk Edit IDs action on the Administration page of the parent Project. To use the automatically generated ID after it has been modified or after you change an existing object name, you can regenerate ID using the Regenerate ID action.
When you copy a project, TeamCity automatically assigns new IDs to all the child elements. The IDs can be previewed and changed in the Copy dialog. When you move an object, its ID is preserved and you might want to use Regenerate ID action to make the ID reflect the new placement.