CODE AND FILES
Code diff checker: compare two files side by side
Paste or open two versions of a file to see every difference side by side, like a desktop diff tool. Changed words are highlighted, and you can step through changes, copy them from one side to the other and export a unified diff. Free, without an account, in your browser.
Your code stays on this page. Files are read in your browser; nothing is uploaded or saved.
Example: a changed settings file
In this fictional JSON file, the version and the debug value change and a language line is added.
Original · settings.json
{
"name": "dashboard",
"version": "1.4.0",
"port": 8080,
"debug": true
}
Changed · settings.json
{
"name": "dashboard",
"version": "1.5.0",
"port": 8080,
"debug": false,
"language": "et"
}
Tip: drop two files at once to fill both sides.
Tip: drop two files at once to fill both sides.
Plain text and code, up to 1,000,000 characters and 20,000 lines per side.
How it works
Lines are aligned with the Myers difference algorithm, also used by GNU diff and Git. Changed blocks sit side by side, with changed words, punctuation and spacing highlighted. Copying a change replaces that block on the other side, and you can undo it. The .diff export uses the standard unified format read by tools such as Git and patch.
Assumptions and limits
Text and code files up to 1,000,000 characters and 20,000 lines per side. Very different files may be aligned approximately, with a notice. Binary files, folder comparison and three-way merges are not supported. Syntax is not highlighted, and code is not run or validated. Files are not uploaded or saved.
Sources & privacyAlgorithm and format references
- Eugene W. Myers: An O(ND) difference algorithm and its variations (1986)
- GNU diffutils: the unified diff format
- Git: diff whitespace and blank-line options
Privacy
Free, with no sign-in. Files and entered text stay in your browser. Recently used stores only tool names and can be cleared. Team settings are saved only when you choose.