OnlyOffice vs Collabora vs CryptPad 2026: Self-Hosted Office Suites

TL;DR

If your priority is opening Microsoft Office files cleanly and editing them in the browser, OnlyOffice is the strongest choice — its formats are OOXML-native. If you already run LibreOffice on the desktop and want the same engine on the server, Collabora Online is the natural fit. If you want end-to-end encrypted documents that even the server operator cannot read, CryptPad is the only option in the category. All three plug into Nextcloud; none of them is a perfect Office 365 clone, and each makes a different bet about what "office in the browser" means.

Key Takeaways

OnlyOffice Document Server — AGPL-3.0; Microsoft format fidelity is the best in the category
Collabora Online — Mozilla Public License 2.0; LibreOffice engine running headless and rendered to the browser
CryptPad — AGPL-3.0; client-side end-to-end encryption; the documents themselves are opaque to the server
All three integrate with Nextcloud and ownCloud; OnlyOffice and Collabora also embed in Seafile, OpenProject, and Confluence
Document fidelity (best to lossiest for .docx/.xlsx/.pptx): OnlyOffice → Collabora → CryptPad
Encryption posture (most to least private): CryptPad → Collabora/OnlyOffice (server has plaintext)
Best fit: OnlyOffice for Office-heavy orgs; Collabora for ODF-first orgs; CryptPad for privacy-critical workflows

Decision Table

Capability	OnlyOffice	Collabora Online	CryptPad
License	AGPL-3.0	MPL-2.0	AGPL-3.0
Native formats	OOXML (`.docx`, `.xlsx`, `.pptx`)	ODF (`.odt`, `.ods`, `.odp`)	Custom encrypted; export to ODF/OOXML/PDF
Office format fidelity	✅ Excellent	✅ Good	⚠️ Limited (export only)
Real-time collaboration	✅	✅	✅
Comments, suggestions, track changes	✅	✅	⚠️ (basic in Pad/Doc)
End-to-end encryption	❌	❌	✅
Desktop apps	✅ Linux/macOS/Win	✅ (LibreOffice)	❌ (PWA)
Mobile apps	✅ iOS / Android	⚠️ via Nextcloud apps	⚠️ PWA
Nextcloud integration	✅ Official	✅ Official	✅ via app
Resource requirements	4 GB RAM, 2 vCPU	4 GB RAM, 2 vCPU	1 GB RAM, 1 vCPU
User license limits (free)	Unlimited	20 connections / 10 docs (free)	None
Self-hostable	✅	✅ (Code is free, Online has limits)	✅

OnlyOffice: Microsoft Format Fidelity

OnlyOffice is the suite that takes OOXML seriously. Its Document Server reads and writes .docx, .xlsx, and .pptx natively — not by converting to ODF and back. For organizations that exchange Office files with external partners, that one fact often decides the comparison.

Strengths

Best-in-class fidelity for Microsoft formats — complex Word documents and spreadsheets survive a round-trip
Modern UI that genuinely resembles the Office 365 web apps
Real-time collaboration with comment threads, track changes, and review workflow
AGPL community edition has no user cap when self-hosted
First-party desktop apps (Linux/macOS/Windows) and mobile apps (iOS/Android)
Integrates with Nextcloud, ownCloud, Seafile, Confluence, Alfresco, OpenProject, and many more
Macros support via JavaScript-style scripting

Weaknesses

Heavy install — Document Server wants 4 GB RAM and a current Linux
The Community Edition's connection limit was removed but enterprise support still gates some features (e.g., advanced auditing, SSO)
AGPL is friction for some enterprise deployments

Choose OnlyOffice if your organization regularly exchanges Microsoft Office files and you need them to look right.

Collabora Online: LibreOffice in the Browser

Collabora Online is LibreOffice rendered server-side and streamed into a browser canvas. It's the official "online" project from the Collabora Productivity team and the most common choice in Nextcloud-centric deployments.

Strengths

Same engine as LibreOffice — your power users on the desktop see exactly the same behavior in the browser
Excellent ODF support (it is the reference implementation)
MPL-2.0 license is friendlier than AGPL for many enterprises
"Collabora Online Development Edition" (CODE) is freely self-hostable; supported "Collabora Online" requires a contract for production use beyond small thresholds
Works with Nextcloud, ownCloud, EGroupware, and most major file collaboration suites
Real-time co-editing on Documents, Spreadsheets, and Presentations

Weaknesses

Microsoft format fidelity is good but not as clean as OnlyOffice for complex .docx/.xlsx
The free CODE has documented limits (20 simultaneous connections / 10 documents) intended for evaluation
The UI shows its desktop heritage — denser than OnlyOffice's

Choose Collabora if your standard format is ODF, you already love LibreOffice on the desktop, or you specifically want the MPL license posture.

CryptPad: Encryption-First

CryptPad is fundamentally different from the other two. It is a client-side end-to-end encrypted suite where the server stores only opaque ciphertext — even if your server is compromised, the documents are unreadable without the URL fragment that contains the key.

Strengths

Genuine end-to-end encryption; the server (and the operator) cannot read documents
Includes Pad, Code, Sheet, Slide, Kanban, Whiteboard, Form, and a Drive — the last is also encrypted
Anonymous sharing via "magic links" — no account required to collaborate
Encrypted teams and shared folders for organizational use
Active development by XWiki SAS / OpenPaaS, EU-based, public funding from NLnet
Excellent for privacy-critical industries — journalism, legal, activism, healthcare consultations

Weaknesses

Document fidelity is the weakest of the three; exports to OOXML/ODF are basic
Cannot do server-side rendering, OCR, or full-text search across encrypted content (by design)
Sheet is functional but not Excel-equivalent for complex spreadsheets
The mental model (URL = key) is unusual; users must understand that losing the URL means losing the document

Choose CryptPad if confidentiality is non-negotiable and the office suite is for human communication rather than complex business documents.

Nextcloud Integration

All three are first-class citizens inside Nextcloud — arguably the most common deployment context for any of them.

OnlyOffice ships an official Nextcloud app; the Document Server runs alongside Nextcloud (separate container) and renders documents stored in Nextcloud Files
Collabora Online has the most established Nextcloud integration — most "edit document in Nextcloud" tutorials default to Collabora
CryptPad integrates via the CryptPad Nextcloud app, but operates on its own encrypted store rather than Nextcloud Files

If you are already on Nextcloud, see the Nextcloud self-hosting guide for the broader stack and open source alternatives to Dropbox if you're still picking your file layer.

Performance Notes

OnlyOffice scales by adding more Document Server containers behind a load balancer; ~50 concurrent users per 4 GB / 2 vCPU node is a reasonable starting target
Collabora uses a fork-per-document model; sizing is by concurrent open documents, not user count — plan ~20 documents per 4 GB / 2 vCPU node
CryptPad is much lighter because the server isn't rendering documents — it's just shuttling encrypted blobs and presence updates

For 100-seat organizations, expect to provision a dedicated VM for OnlyOffice or Collabora; CryptPad can usually share infrastructure.

Migration Notes

Google Docs / Microsoft 365 → OnlyOffice: Direct file uploads work cleanly; complex collaboration history (comments, suggestions) survives partially
OnlyOffice → Collabora: Files transfer cleanly; expect minor formatting drift on complex .docx
Anything → CryptPad: Files import into CryptPad as PDF/ODF; you'll lose advanced formatting

For Office-heavy organizations, the path that loses the least fidelity over a multi-year horizon is to standardize on OOXML and use OnlyOffice as the editor — the formats remain interchangeable with the rest of the world.

Who Should Choose What

Choose OnlyOffice if:

You exchange .docx and .xlsx files with the outside world
You want the most Office-365-like browser experience
You operate beyond Collabora's free-tier connection limits

Choose Collabora if:

You're an ODF-first organization or government deployment
You already trust LibreOffice on the desktop
The MPL license posture matters more than minor fidelity gaps

Choose CryptPad if:

You handle confidential information and need cryptographic guarantees, not just access controls
You're a journalist, legal team, healthcare provider, or activist organization
You're willing to trade format fidelity for privacy

Verdict

For most organizations migrating off Microsoft 365 in 2026, OnlyOffice is the pragmatic default — it minimizes the "documents look broken now" complaints from non-technical staff. Collabora is the right answer for ODF-first or LibreOffice-aligned organizations. CryptPad is in a league of its own for confidentiality and worth running even alongside one of the other two for the documents that genuinely need encryption.

The SaaS-to-Self-Hosted Migration Guide (Free PDF)