Bitbucket is Atlassian's Git repository hosting service, offering code collaboration, pull requests and built-in CI/CD with tight integration to Jira for professional software teams.
GitHub is a Microsoft-owned code hosting platform based on Git, offering repositories, pull requests, Actions CI/CD, Copilot and collaboration tools for open source and enterprise developers.
Atlassian is an Australian software company behind Jira, Confluence, Trello and Bitbucket, offering collaboration and project tracking tools used by software and business teams.