ONLYOFFICE Document Server is a free collaborative online office suite comprising viewers and editors for texts, spreadsheets and presentations, fully compatible with Office Open XML formats: .docx, .xlsx, .pptx and enabling collaborative editing in real time.
ONLYOFFICE Docs can be used as a part of ONLYOFFICE Workspace or with third-party sync&share solutions (e.g. Nextcloud, ownCloud, Seafile) to enable collaborative editing within their interface.
It has three editions - Community, Enterprise, and Developer.
Official website: https://www.onlyoffice.com
Code repository: https://github.com/ONLYOFFICE/DocumentServer
License: GNU AGPL v3.0
ONLYOFFICE Docs on official website: http://www.onlyoffice.com/office-suite.aspx
ONLYOFFICE Workspace on official website: https://www.onlyoffice.com/workspace.aspx
List of available integrations: http://www.onlyoffice.com/all-connectors.aspx
If you have any problems with or questions about ONLYOFFICE Document Server, please visit our official forum to find answers to your questions: forum.onlyoffice.com or you can ask and answer ONLYOFFICE development questions on Stack Overflow.