#1★ TOP PICK
LibreOffice
The mature, fully open-source desktop office suite that runs entirely on your own machine.
100
OPEN SOURCEMPL-2.0SELF-HOSTLOCAL-FIRST
LibreOffice is the most complete free desktop office suite and the closest all-round replacement for the Word/Excel/PowerPoint apps. It bundles Writer, Calc, Impress, Draw, Base, and Math, runs on Windows, macOS, and Linux, and opens and saves Microsoft's DOCX, XLSX, and PPTX files as well as the open OpenDocument (ODF) formats. It is produced by the non-profit Document Foundation, installs locally with no account or cloud, and costs nothing. It is the right pick for individuals and organizations that mainly need capable offline documents and full control over their files. Its main gap versus 365 is native real-time co-authoring in the desktop apps; browser-based simultaneous editing comes from the related Collabora Online project, listed below.
Strengths
- +Fully open-source under MPL-2.0, an OSI-approved license
- +Runs entirely offline on your own computer with no account, subscription, or cloud
- +The most feature-complete free desktop suite: word processor, spreadsheet, presentations, plus Draw, Base, and Math
- +Reads and writes Microsoft's DOCX/XLSX/PPTX as well as the open ODF formats, so files stay portable
- +Backed by the non-profit Document Foundation with a very active release cadence and large community
Trade-offs
- −No built-in real-time co-authoring in the desktop apps; browser-based simultaneous editing needs the related Collabora Online
- −Complex Microsoft documents (heavy macros, advanced pivot tables, intricate formatting) can shift slightly on import/export
- −No bundled cloud storage, email, or team-chat equivalent to OneDrive/Outlook/Teams
- −The interface and defaults differ from Microsoft's, so there is a short adjustment period
#2
ONLYOFFICE
Open-source suite with the closest Microsoft-format fidelity and real-time co-editing.
97
OPEN SOURCEAGPL-3.0SELF-HOSTLOCAL-FIRST
ONLYOFFICE is an open-source office suite whose editors use Office Open XML (DOCX, XLSX, PPTX) as their native formats, which gives it some of the best fidelity with Microsoft files of any alternative here. It comes in two parts: the free ONLYOFFICE Desktop Editors, an offline app for Windows, macOS, and Linux; and ONLYOFFICE Docs (Document Server), a self-hostable engine that adds real-time co-authoring, comments, track changes, and version history in the browser. Both are AGPL-3.0 licensed. It is a strong fit for teams that want Microsoft-like documents plus self-hosted collaboration on infrastructure they control. The vendor also sells hosted cloud and enterprise editions.
Strengths
- +AGPL-3.0 licensed and genuinely open, for both the desktop editors and the Docs server
- +Uses DOCX/XLSX/PPTX as native formats, giving very high fidelity with Microsoft files
- +Self-hostable Docs server adds real-time co-authoring, comments, and track changes on your own infrastructure
- +Free offline desktop apps for Windows, macOS, and Linux for users who do not need collaboration
- +Actively developed with a regular release cadence and integrations for Nextcloud, ownCloud, and others
Trade-offs
- −Real-time collaboration requires running and maintaining the Docs server, which needs a capable server
- −The free self-hosted Community edition is intended for smaller deployments; heavier or enterprise use points to the paid editions
- −Some advanced features and official support sit behind the paid cloud/enterprise tiers
- −As a newer suite, it has a smaller extension ecosystem than the most established desktop suites
Free desktop apps and self-hosted Community server; paid cloud and enterprise editions available #3
Collabora Online
Self-hosted, browser-based collaborative editing built on the LibreOffice engine.
95
OPEN SOURCEMPL-2.0SELF-HOSTLOCAL-FIRST
Collabora Online is a self-hostable, browser-based office suite from Collabora that brings real-time co-authoring to the LibreOffice engine, so multiple people can edit the same Writer, Calc, or Impress document at once through a web browser. The free Collabora Online Development Edition (CODE) is a rolling release aimed at home use, testing, and small teams, while the supported Collabora Online product targets organizations that need stability and vendor support. It is the natural way to add Google-Docs-style collaboration on your own server, and it is what powers Nextcloud Office (the richdocuments app) inside a Nextcloud instance. It is MPL-2.0 licensed.
Strengths
- +Fully open-source under MPL-2.0, an OSI-approved license
- +Real-time, in-browser co-authoring of documents, spreadsheets, and presentations on a server you control
- +Built on the mature LibreOffice engine, so format handling matches LibreOffice closely
- +Powers Nextcloud Office, giving an easy path for people already running Nextcloud
- +Supports ODF and Microsoft formats, keeping documents portable
Trade-offs
- −Requires running a server; setup and maintenance are more involved than a desktop install
- −The free CODE edition is a rolling release the vendor does not recommend for production; production use points to the paid supported edition
- −Best used alongside a file backend such as Nextcloud, rather than as a standalone suite
- −Browser-based editing depends on the server being available, so it is less 'offline-first' than a desktop app
Free self-hosted CODE edition; paid supported edition and hosting available #4
CryptPad
End-to-end-encrypted collaborative documents where the server never sees your content.
92
OPEN SOURCEAGPL-3.0SELF-HOSTLOCAL-FIRST
CryptPad is a privacy-first collaboration suite built around end-to-end encryption: documents, spreadsheets, presentations, and more are encrypted in your browser, so a self-hosted or public server stores only ciphertext and cannot read your content. It supports real-time co-editing, shared folders, and a range of app types, and it is AGPL-3.0 licensed and self-hostable via Docker or a Debian install. Developed by XWiki SAS with public-interest funding, it also runs a free public instance at cryptpad.fr. It is the strongest choice when confidentiality is the priority; the trade-off is that it is a distinct web workspace rather than a drop-in Microsoft-format editor.
Strengths
- +AGPL-3.0 licensed and self-hostable via Docker or Debian, so you can own the whole stack
- +End-to-end encryption means the server stores only encrypted data and cannot read your documents
- +Real-time collaborative documents, spreadsheets, presentations, and shared drives in the browser
- +A free public instance (cryptpad.fr) lets you try it with no setup
- +Actively maintained by XWiki SAS with sustained public-interest funding
Trade-offs
- −It is a browser-based encrypted workspace, not a full desktop suite or a drop-in Microsoft-format editor
- −Compatibility with complex Microsoft documents is more limited than ONLYOFFICE or LibreOffice
- −The encryption model means account recovery and some integrations work differently from conventional suites
- −Self-hosting requires running a server, and encrypted real-time editing is heavier than plain document storage
Free / self-host; free public instance at cryptpad.fr