← Blogby Marcell Almeida

How to convert documents online with Pandoc WASM

Upload a document, pick an output format, preview, and download — Pandoc runs entirely in your browser.

Need DOCX → HTML, EPUB → Markdown, or ODT → DOCX? The Document Converter uses Pandoc compiled to WebAssembly for universal document conversion. Nothing is uploaded to a server.

Try it — upload a document to convert

Open full tool →

How it works

  1. Upload — drop or select DOCX, EPUB, HTML, Markdown, ODT, RTF, CSV, TSV, JSON, RST, DocBook, or TXT.
  2. Load Pandoc — first visit downloads ~56 MB of WASM (cached afterward).
  3. Convert & download — pick an output format, preview text/HTML, download — or get a ZIP when images are extracted.

Why Pandoc WASM?

Lightweight JS libraries (mammoth, turndown) cover narrow cases. Pandoc is the universal document converter — battle-tested for DOCX, EPUB, ODT, RST, and cross-format transforms. maratool runs Pandoc in a browser worker via the official pandoc-wasm npm package.

Limitations

PDF output is not available in the browser — Pandoc needs LaTeX or similar engines that cannot run in WASM. JSON input must be Pandoc's native JSON format (not arbitrary JSON). Legacy .doc files use the DOCX reader and may fail. Large files are limited by browser memory.

The Document Converter is free, runs locally, and never sends your data to a server. More document converter tools at maratool.com.