Pandoc in the browser: a Markdown to Word converter with no server

[hassanrazeen]

I built https://md-to-word.com/, a free Markdown to Word converter where the conversion happens in the visitor's browser and nothing is uploaded. Pandoc does the heavy lifting.

There are two engines. A small one (markdown-it plus the docx library) drives a live preview and handles everyday documents, warning about anything it had to simplify. The optional "Best quality" mode runs Pandoc 3.10 compiled to WebAssembly, via pandoc-wasm 1.1.0, in a Web Worker: LaTeX math becomes editable Word equation objects (OMML) and Markdown footnotes become real Word footnotes.

Notes that might be useful to others doing this:

• The binary is about 56 MiB on disk and about 15 MiB over the wire. Cloudflare Pages rejects assets over 25 MiB, so it is fetched from unpkg at runtime and kept in the Cache API, which makes the second visit instant. It is strictly opt-in behind a checkbox that says what it costs.
• Importing the package normally makes Vite 8 and Turbopack choke on the .wasm import in the browser entry point. Using src/core.js, which takes the binary as a parameter, avoids that; I wrote it up on pandoc-wasm#11.
• A Content-Security-Policy needs 'wasm-unsafe-eval' in script-src and the wasm origin in connect-src. Nothing else.
• It runs in a worker so the download and conversion never block typing, and falls back to the lighter engine if the wasm cannot be fetched.

Pandoc's GPL licence and links to the source are on the About page. Thank you for the tool; being able to run it client-side is the reason this site can be free and private at the same time.