Chrome extension · free · MIT

Stop paying tokens
for PDFs, Excels, DOCX & more.

Diffsurge MD intercepts PDFs, Excel spreadsheets, DOCX documents, and more that you drop into ChatGPT, Claude, Gemini and DeepSeek and converts them to clean Markdown before they upload. Runs entirely in your browser via Microsoft MarkItDown on Pyodide. Nothing leaves your machine.

PDF
~30k
Markdown
~8k
How to install →

Local by default

MarkItDown runs in a WASM Python worker inside the extension. Your files never touch a server.

Fewer tokens

A 40-page PDF drops from ~30k tokens to ~8k. Faster replies, less spend, better recall.

Works everywhere

ChatGPT, Claude, Gemini, DeepSeek. Drag-drop or click-to-upload. Falls back silently if a site changes.

Install

  1. Download and unzip the file above.
  2. Open chrome://extensions and enable Developer mode (top-right).
  3. Click Load unpacked and select the unzipped folder.
  4. Open any supported chat, drop a PDF or DOCX, and watch the toast: "~4,200 tokens saved".

First conversion warms up the Python runtime (~10–20s). After that it's cached and near-instant.

Optional cloud engine

For audio transcription or files too large for the browser, a self-hosted Go + MarkItDown container ships in backend/. Deploy it on Fly.io's or Render's free tier, then enable it in the extension options. This path does upload files to your server — strictly opt-in.