Gitter is a real-time chat system similar to Slack or IRC, but with an emphasis on ease of use for open-source communities, especially those using GitHub. For example, Gitter provides a "badge" that can be placed in a GitHub project's README file that allows users to join a Gitter chat with a single click. Rather than creating a dedicated Gitter account, users can sign in using either their Github or their Twitter credentials. Messages can be formatted using GitHub-flavored Markdown and can contain inline media files. Message archives are both browseable and searchable by month. In addition to Github integration, Gitter also integrates with Trello, Jenkins, Travis CI, Drone, Heroku, and Bitbucket. Public Gitter chats are provided with unlimited message history and can use all available integrations. Source code for Gitter is available under the MIT license on gitlab.org and the service can be self-hosted if users wish to do so. In addition to the web client, which works in any modern browser, device-specific Gitter clients are available for Windows, macOS, Linux, Android, and iOS.