text.compare
See exactly what changed.
Compare text, code, documents, data and images. Free, no ads, and comparing happens entirely in your browser.
Comparing text shouldn’t come with ads
Comparing two pieces of text is a simple job, but I got tired of the free diff sites that wrap it in banner ads, cookie walls and upsells. Many of them also upload whatever you paste. That's a bad deal when the text is a contract, a config file with secrets, or your own writing.
So I built the diff tool I wanted instead: fast, clean, private by design, and good at the hard cases like moved code, reformatted JSON, PDFs and Word documents. I made it open source so anyone can check how it works or run their own copy.
Good at the hard cases
Private by design, fast by default
Myers O(ND) diff engine
Linear-space Myers with middle-snake bisection and a time budget, so an 8 MB log against an edited copy finishes in about two seconds instead of freezing the tab.
Moved-block detection
Code that moved is shown in violet with a “Moved to line 12” tag that jumps to the other copy, instead of a big deletion plus a big addition.
Ignore what doesn’t matter
Case, whitespace, blank lines, or any pattern: ready-made ones for dates, GUIDs and hex values, or your own regular expressions for log files.
End-to-end encrypted accounts
Optional sign-in syncs your library, encrypted in the browser with AES-256-GCM under a key only your passphrase can unlock.
Share links with no server
The whole comparison is compressed into the part of the link after #, which browsers never send to a server.
Runs anywhere
A folder of static files. Host it on a Raspberry Pi, a $5 VPS, GitHub Pages or Docker, with no database and no outside services.
Don’t take my word for it, read the code
A privacy promise is only worth something if you can check it. The README links each privacy claim to the source that makes it true, and 123 unit tests plus 36 browser tests run on every push and pull request.
Run your own copy in a couple of minutes
It's a folder of static files with no database and no server code, so it runs anywhere that serves files.
$ git clone https://github.com/JamesClayPatton/text-compare.git$ cd text-compare && npm install && npm run build