Gitter is an open-source instant messaging and chat room system for developers and users of GitLab and GitHub repositories.

[3] Gitter is provided as software as a service, with a free option providing all basic features and the ability to create a single private chat room, and paid subscription options for individuals and organisations, which allows them to create arbitrary numbers of private chat rooms.

A graphical badge linking to the chat room can then be placed in the git repository's README file, bringing it to the attention of all users and developers of the project.

[8] On February 13, 2023, Gitter migrated their service to a custom-branded Matrix instance that uses Element for its web interface.

[8] On February 13, 2023, Gitter migrated their service to a custom-branded Matrix instance that uses Element for its web interface.