Compare two .env / config files in your browser and see only the real differences — because a deploy shouldn't break over a reordered line or a stray quote.
Diffing env files with diff is noisy: it flags reordered keys, reindentation, changed quoting and comment edits that don't actually change any value. dotdiff normalizes both sides first — ignoring key order, whitespace, quotes and comments — so what's left is the difference that matters: keys added, removed, or whose value genuinely changed. On top of the diff it runs a health check that catches the mistakes that quietly break environments: duplicate keys, empty values, type drift, and required keys missing from one side.
It's a single static page. Everything runs client-side, and a strict Content-Security-Policy (connect-src 'none') means the page has no way to make a network request — so you can paste production secrets without them ever leaving your device.
- Normalize-then-diff — ignore key order, whitespace, quotes and inline
#comments (each toggleable). - Health check — flags duplicate keys, empty/unset values, value-type drift, and missing required keys.
- Secret-safe — a "mask values" mode hides values in the on-screen report and the download.
- Raw text mode — line-by-line diff when you need it, with optional de-duplication.
- Export — copy the report or download it as a
.txt. - Offline & private — no account, no upload, no server; works offline once loaded.
npm install # install dependencies
npm run dev # local dev server with hot reload
npm run build # static production build → dist/
npm run preview # serve the production build locallyBuilt with Astro. The build is fully static — deploy dist/ to any static host.
dotdiff is provided as is, without warranty of any kind, express or implied. It is a convenience tool: always verify its results before acting on them, especially when changes affect production configuration or secrets. The author accepts no liability for any loss or damage arising from its use. See LICENSE for the full terms.
MIT © 2026 Sreenivas Sadhu Prabhakara