6 Best Open Source Microsoft 365 Alternatives
A curated collection of the 6 best open source and self-hosted alternatives to Microsoft 365 in 2026.
Looking for a free, privacy-friendly, or self-hosted replacement for Microsoft 365 in 2026? The top open-source alternative is Tuta — Tuta offers encrypted email, calendar and contacts with quantum-resistant security, protecting your privacy without ads or tracking..
Other highly rated open-source Microsoft 365 alternatives include CryptPad, Papra and ONLYOFFICE Docs.
Tuta offers encrypted email, calendar and contacts with quantum-resistant security, protecting your privacy without ads or tracking.
Tuta offers encrypted email, calendar and contacts with quantum-resistant security, protecting your privacy without ads or tracking.
Open-source collaboration suite offering encrypted document editing, file sharing, and team workspaces with complete privacy protection.
Open-source collaboration suite offering encrypted document editing, file sharing, and team workspaces with complete privacy protection.
A document management platform that helps you archive, organize, and search files with email ingestion, tagging capabilities, and powerful search functionality.
A document management platform that helps you archive, organize, and search files with email ingestion, tagging capabilities, and powerful search functionality.
Open-source online editor for documents, spreadsheets, presentations, and PDFs. Features real-time collaboration, AI integration, and accessibility tools.
Open-source online editor for documents, spreadsheets, presentations, and PDFs. Features real-time collaboration, AI integration, and accessibility tools.
Complete free office suite compatible with Microsoft formats (.doc, .docx, .xls, .xlsx, .ppt, .pptx). Open source alternative with regular updates.
Complete free office suite compatible with Microsoft formats (.doc, .docx, .xls, .xlsx, .ppt, .pptx). Open source alternative with regular updates.
Powerful online document editor with Microsoft Office compatibility. Integrate into your infrastructure or use trusted hosting partners for secure team collaboration.
Powerful online document editor with Microsoft Office compatibility. Integrate into your infrastructure or use trusted hosting partners for secure team collaboration.
About Microsoft 365
A cloud-based suite of business applications from Microsoft that includes Office 365, SharePoint, Exchange, and Teams.