ooxml.dev is an interactive reference for ECMA-376 (Office Open XML) — the standard behind .docx, .xlsx, and .pptx files. Built by the SuperDoc team, who implemented a native OOXML renderer from scratch. Features: live previews (edit XML, see it render in real-time using SuperDoc's native OOXML engine), implementation notes (documents real-world behavior where Microsoft Word diverges from the spec), semantic spec search (18,000+ spec chunks searchable by meaning via MCP server at api.ooxml.dev/mcp), and practical guides for paragraphs, tables, borders, bidirectional text, and document creation. The OOXML spec is 5,000+ pages of PDFs with no rendering guidance — this site bridges that gap with knowledge from people who actually implemented the spec. Covers WordprocessingML (the .docx subset). SuperDoc is open source at superdoc.dev. Built by Caio Pizzol (caiopizzol.com), Head of DX at SuperDoc.

OOXML reference from your terminal

Search the ECMA-376 specification and inspect OOXML schemas without leaving your terminal.

Install

Node.js 20 or later is required.

npm install --global @ooxml-dev/cli

Try it

ooxml login
ooxml search "paragraph spacing"
ooxml element w:p

The CLI uses the free, hosted ooxml.dev service. You may need to create an account and sign in. Sign-in is only used to control usage.

Use it with a coding agent

npx skills add superdoc/ooxml-dev --skill research-ooxml -g -y