Get involved

You can open a collaborative presentation in one app and continue editing it in another — as long as both apps speak the same format. But today, no open standard defines how a real-time collaborative document should be structured. Every platform invents its own proprietary model, and your documents are trapped inside whichever tool you started with.

We are designing open, CRDT-based document format specifications so that collaborative documents can move freely between applications. We need people who care about document freedom to help us get it right.

The problem: no open standards for collaborative documents

Traditional document formats like ODF and OOXML define how a finished document looks — paragraphs, cells, slides. But they have no concept of the structures that make real-time collaboration work: CRDT state, concurrent edit resolution, operational history, or presence information.

As a result, every collaboration platform builds its own proprietary data model:

  • Google Docs, Sheets, and Slides use internal formats that are never exposed
  • Microsoft 365 layers proprietary real-time structures on top of OOXML
  • Notion, CryptPad, ONLYOFFICE, and others each have their own approach
  • None of these formats are documented, interoperable, or standardized

The consequence is vendor lock-in at the collaboration layer. Even when the static export format is open, the collaboration data model is not. You cannot take a collaboratively edited document from one platform and continue collaborating on it in another without losing structure, history, and concurrent editing capability.

Document Freedom Day 2026

Document Freedom Day is March 25, 2026 — an annual celebration of open document standards and the right to communicate freely. The need for open collaborative document formats is exactly the kind of challenge DFD exists to highlight.

What we are building

We are creating open, documented format specifications for collaborative document types:

  • Prezillo — Collaborative presentations (14 object types, style system, templates)
  • Calcillo — Collaborative spreadsheets (cells, formulas, multi-sheet)
  • Ideallo — Collaborative whiteboards (9 object types, linked copies)
  • Notillo — Collaborative notes (planned)
  • Quillo — Collaborative rich text editor (planned)

These formats are built on Yjs CRDTs (Conflict-free Replicated Data Types), which allow multiple users to edit the same document simultaneously without conflicts and without a central server deciding the outcome.

Each specification documents the exact data structures, field names, types, and relationships — enough for any developer to build a compatible reader, writer, or editor. See the Document Formats overview for the full specifications and the CRDT Design Guide for the patterns and principles behind the format design.

Early stage

These specifications are working documents, not ratified standards. The formats are implemented in Cloudillo apps and are actively used, but they have not gone through a formal standardization process. Community review and feedback at this stage has the most impact — the designs are mature enough to be meaningful but flexible enough to incorporate improvements.

How you can help

Review and critique the format specifications

Read through the Prezillo, Calcillo, and Ideallo format specs. Look for ambiguities, missing edge cases, unnecessary complexity, or things that would make implementation difficult. File issues or start discussions on GitHub.

Design formats for new document types

Notillo (notes) and Quillo (rich text) are planned but not yet specified. If you have experience with collaborative text editing, rich text data models, or CRDT-based editors, your input on these formats would be valuable. The CRDT Design Guide describes the patterns we follow.

Test concurrent editing scenarios

Collaborative formats need to handle multi-user editing, conflict resolution, offline edits, and large documents gracefully. Testing these scenarios and reporting issues helps ensure the formats work in practice, not just on paper.

Contribute to standardization efforts

If you have experience with standards bodies (OASIS, W3C, IETF) or with the ODF/OOXML standardization process, your perspective on how to move these specifications toward formal standardization is welcome.

Spread the word

Share this page with people who care about document freedom, open standards, and interoperability. The more eyes on these formats, the better they will be.

Where to start

About Cloudillo

Cloudillo is an open-source, decentralized collaboration platform where each user or organization hosts their own data while collaborating globally through federation. The collaborative document formats described here are part of that platform, but the formats themselves are designed to be useful to anyone building collaborative tools — you do not need to use Cloudillo to benefit from or contribute to these specifications. Learn more at What is Cloudillo?.

See also