https://github.com/superdoc-dev/ooxml-dev
Interactive OOXML (ECMA-376) reference explained by people who actually implemented it
https://github.com/superdoc-dev/ooxml-dev
documentation docx ecma-376 microsoft-word office-open-xml ooxml reference wordprocessingml
Last synced: 18 days ago
JSON representation
Interactive OOXML (ECMA-376) reference explained by people who actually implemented it
- Host: GitHub
- URL: https://github.com/superdoc-dev/ooxml-dev
- Owner: superdoc-dev
- Created: 2026-01-13T11:56:52.000Z (3 months ago)
- Default Branch: main
- Last Pushed: 2026-03-22T00:02:47.000Z (about 1 month ago)
- Last Synced: 2026-04-02T08:24:51.994Z (26 days ago)
- Topics: documentation, docx, ecma-376, microsoft-word, office-open-xml, ooxml, reference, wordprocessingml
- Language: TypeScript
- Homepage: https://ooxml.dev
- Size: 857 KB
- Stars: 4
- Watchers: 0
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- Agents: AGENTS.md
Awesome Lists containing this project
README
[](https://ooxml.dev)
[](https://api.ooxml.dev/mcp)
[](https://opensource.org/licenses/MIT)
The OOXML spec, explained by people who actually implemented it.
## What is this?
An interactive reference for ECMA-376 (Office Open XML) built by the [SuperDoc — DOCX editing and tooling](https://superdoc.dev) team. Every page combines XML structure, live rendered previews, and implementation notes that tell you what the spec doesn't.
- **Live previews** — Edit XML and see it render in real-time. Every example is a working document.
- **Implementation notes** — Where Word diverges from the spec, what will break your code, and what to do about it.
- **Semantic spec search** — 18,000+ spec chunks searchable by meaning via MCP server.
## Why?
The ECMA-376 spec is 5,000+ pages and it lies. Word's actual behavior diverges from the standard in ways you only discover by building against it. The knowledge to implement OOXML correctly is locked inside a handful of companies that have no incentive to share it.
We faced this at SuperDoc — building a document engine on native OOXML with no roadmap beyond an unreliable spec. We wrote down everything we learned and made it public. No one should have to reverse-engineer Word alone.
## MCP Server
Search the ECMA-376 spec with AI. Ask questions in natural language, get answers grounded in the actual specification.
```bash
claude mcp add --transport http ecma-spec https://api.ooxml.dev/mcp
```
Works with Claude Code, Cursor, and any MCP-compatible client. Three tools: `search_ecma_spec` (semantic search), `get_section` (by ID), and `list_parts` (browse structure).
## Development
```bash
bun install # Install dependencies
bun dev # Dev server at http://localhost:5173
bun run build # Production build
```
## Contributing
Contributions welcome. Add implementation notes, fix examples, or improve the reference.
## License
MIT
---
Built by 🦋 [SuperDoc — DOCX editing and tooling](https://superdoc.dev)