You can import issues from Jira, GitHub, Mantis, Redmine, and Bugzilla, and migrate tasks and projects from one YouTrack instance to another.
A full history of commit messages and pull requests from TeamCity, GitHub, GitLab, and BitBucket Cloud can also be added to imported YouTrack issues. To make this work, import tasks that include the VCS changes history and set up an integration with your VCS.
YouTrack can be configured to import continuously from Jira and GitHub. When continuous import is enabled, YouTrack checks the connected Jira or GitHub instance for changes in the imported projects every 10 minutes. Issues that have been added or updated since the previous check are imported and updated in YouTrack.
You can import entire Confluence spaces to YouTrack Knowledge Base, complete with articles, comments, and even users. Import works with cloud and self-hosted Confluence installations.