Alternatives / Microsoft 365
These tools replace different parts of Microsoft 365: desktop and browser office suites, encrypted email and calendars, collaborative documents, and document archiving. A full migration usually combines several projects rather than relying on a single exact substitute.
Written by Maxime DERAME
Last updated:
Microsoft 365 spans office editing (Word, Excel, PowerPoint), communication (Outlook, Exchange, Teams), storage and knowledge (OneDrive, SharePoint), and collaboration (Office Online, shared calendars, Forms). No project here replaces every layer; a realistic open-source setup combines multiple tools.
ONLYOFFICE Docs focuses on browser-based editing and compatibility with Microsoft Office formats. LibreOffice provides a mature offline desktop suite. Collabora Online brings LibreOffice technology to collaborative browser-based editing. CryptPad prioritizes privacy and encryption, with less emphasis on Office file compatibility.
Tuta is the email, calendar, and contacts option in this comparison. It provides hosted encrypted mail and clients but not a complete publicly self-hostable server stack. Organizations requiring self-hosted mail infrastructure need a dedicated mail server in addition to an office suite.
Papra covers document management and archiving, but it is not a complete file-sync or collaboration platform. CryptPad includes encrypted file storage alongside collaborative documents. A broader migration may pair an office editor with a file platform such as Nextcloud.
LibreOffice is primarily desktop software, making it a fit for offline access, local files, and no-account use. ONLYOFFICE Docs, Collabora Online, and CryptPad emphasize browser-based collaboration and centralized editing, which requires server infrastructure.
CryptPad encrypts documents in the browser before sending them to the server. Tuta applies a similar privacy-first approach to email, calendar, and contacts. LibreOffice works locally by default. Self-hosting ONLYOFFICE or Collabora gives infrastructure control, but not the same zero-knowledge document model as CryptPad.
A more complete deployment could combine Nextcloud for files, calendar, contacts, and collaboration; ONLYOFFICE Docs or Collabora Online for office editing; a dedicated mail server or encrypted provider for email; and Matrix or another collaboration platform for messaging and calls. This provides more infrastructure control but requires operating multiple services.
Organizations look beyond Microsoft 365 for open-source software, self-hosting, on-premises deployment, data sovereignty, offline office apps, open formats, control over backups, or less dependence on Microsoft accounts and per-seat subscriptions. Microsoft 365 combines Word, Excel, PowerPoint, Outlook, Exchange, OneDrive, SharePoint, Teams, calendars, forms, and cloud storage, so alternatives cover distinct pieces of that suite.
| Alternative | Primary replacement | License | Status | GitHub stars | Self-hosted |
|---|---|---|---|---|---|
| Tuta | Outlook / Exchange / Calendar | GPL-3.0 client | Open-source client / hosted service | ~7.9k | No full server stack |
| CryptPad | Office + collaborative docs | AGPL-3.0-or-later | Open source | ~8k | Yes |
| Papra | SharePoint-style document archive | AGPL-3.0 | Open source | ~5.2k | Yes |
| ONLYOFFICE Docs | Word / Excel / PowerPoint | AGPL-3.0 Community Edition | Open source / commercial editions | ~6.9k | Yes |
| LibreOffice | Word / Excel / PowerPoint desktop | MPL/LGPL multi-license | Open source | ~4.4k mirror | Local |
| Collabora Online | Office Online | Primarily MPL-2.0 | Open source / commercial support | ~3.3k issue repo | Yes |
Want the closest replacement for Word, Excel, and PowerPoint
ONLYOFFICE Docs provides browser-based collaborative editing with a strong focus on DOCX, XLSX, and PPTX compatibility.
Want a completely offline office suite
LibreOffice is a mature cross-platform desktop suite that works locally without an account, server, subscription, or cloud connection.
Want browser-based collaborative office editing
Collabora Online brings LibreOffice technology to a self-hosted browser-based suite, while ONLYOFFICE is another strong option.
Want maximum privacy for collaborative documents
CryptPad encrypts documents in the browser before they reach the server, so the server operator normally cannot read their contents.
Want to replace Outlook and Calendar
Tuta provides hosted end-to-end encrypted email, calendars, contacts, and desktop and mobile applications; it does not publish a complete self-hostable mail server stack.
Need document archiving
Papra focuses on storing, tagging, sharing, and retrieving documents rather than editing office files.
Already use Nextcloud
Collabora Online and ONLYOFFICE Docs both integrate with Nextcloud and can provide browser-based document editing alongside file storage.
Need Microsoft Office file compatibility
ONLYOFFICE emphasizes DOCX, XLSX, and PPTX compatibility; LibreOffice and Collabora also support Microsoft formats and OpenDocument.
Want a complete Microsoft 365 replacement
No single listed project covers every layer. A more complete stack may combine a file and collaboration platform, office editor, mail provider or server, and messaging system.