opendoc: Edit Word Documents with a Rust Engine

Overview

OpenDoc is a local-first editor for Word documents, built on its own deterministic Rust engine. The same engine handles import, editing, layout, and rendering natively, headless, or in the browser through WebAssembly, so the web editor can open and save documents without a document server.

It is aimed at teams that want to embed or brand a document editor, or use a Rust document engine directly. The project emphasizes loss-aware DOCX handling and exports to PDF, HTML, and Markdown as well as DOCX and ODT. It is pre-release, and rendering is not yet identical to Word.

Key Features

• Opens and saves DOCX and ODT, opens RTF and plain text, and exports PDF, HTML, Markdown, and plain text.
• Uses a normalized document model and reports content an export cannot preserve; an unedited DOCX saves byte-for-byte.
• Provides a browser editor with editing, review, version history, comparison, print, and accessibility features.
• Offers an embeddable custom element, in-process API, and postMessage bridge with host-controlled roles and capabilities.
• Includes Rust crates for importing, editing, laying out, rendering, and exporting documents.
• Supports experimental real-time collaboration through an optional relay that forwards changes without holding documents.
• Applies explicit package limits when reading files and refuses macro-enabled DOCM files.

Use Cases

• Embed a local-first document editor in a product where users should open and edit files in the browser without uploading them to a document server.
• Build document workflows in Rust that need DOCX or ODT import, layout, rendering, or export.
• Preview or convert documents headlessly, for example to render pages or generate PDFs.
• Evaluate an open alternative to commercial document editors when pre-release status and imperfect Word rendering are acceptable.

Getting Started

The browser editor requires Rust and wasm-pack:

git clone https://github.com/CasualOffice/opendoc.git && cd opendoc
./webapp/build.sh
./webapp/serve.py

Then open http://localhost:8099/editor.html?demo=1. See the README for Docker, engine, and embedding instructions.

Alternatives

• univer: Univer is a TypeScript SDK for embedding document and other productivity experiences, while OpenDoc is a local-first Word editor with DOCX and ODT support.

Considerations

• The project is new and changing quickly. It has recent development activity and merged pull requests, but no releases in the past year; the available contributor data is concentrated heavily in one person. No issues were closed in the measured recent period.
• The editor and engine are pre-release. The public SDK surfaces are not stable, and the internal crates are not published.
• The browser build requires Rust 1.88 or later and wasm-pack; the README also documents a Docker Compose option.
• Rendering fidelity is still improving. SmartArt is shown as a placeholder, some chart types are placeholders, and equations cannot be edited or inserted. RTF opens but cannot be saved.
• PDF export lacks tags, links, bookmarks, and PDF/A support. Collaboration is experimental, and browser version history is not stored on a server.
• The project is licensed under Apache-2.0. Review its license and bundled third-party asset notices when distributing it.