What is the difference between GitLab and Bitbucket?

GitLab and Bitbucket are both Git-based repository management tools, but they cater to different needs. GitLab is an open-source platform offering a comprehensive DevSecOps solution with high availability and built-in CI/CD, while Bitbucket is tightly integrated with Atlassian tools like Jira and Trello. 

GitLab provides greater flexibility in organizing repositories with nested subgroups, whereas Bitbucket uses workspaces with team-based limitations. Additionally, GitLab's open-source nature allows for more customization, while Bitbucket offers strong built-in security tools at no extra cost.