What makes this diff different
Most online diff checkers show you a wall of red and green and leave you scrolling. This one is built for reviewing real changes:
- Jump between changes with F7 / Shift+F7, Alt+↓ / Alt+↑, or j / k. The counter always tells you where you are (“3 / 12”).
- Overview ruler on the right shows every change in the document at a glance. Click a mark to jump to it.
- Word or character highlights inside modified lines, so a renamed variable doesn’t look like a rewritten line.
- Merge blocks: use the arrows between the two sides to copy a change left or right, with undo.
- Collapse unchanged lines to focus on what changed, and expand any folded region with one click.
- Ignore whitespace, case or blank lines when formatting noise hides the real change.
- Export the result as a standard unified diff (
.patch) thatgit applyunderstands.
How it works
The comparison uses a patience diff: lines that appear exactly once on both sides are used as anchors, and the gaps between them are compared with Myers’ algorithm. The result reads the way a human would describe the change, and large files (tens of thousands of lines) compare in milliseconds.
Line endings are normalized before comparing, so a file saved with Windows CRLF endings and the same file with Unix LF endings do not show every line as changed. You will see a note when the line endings differ.
Privacy
Both texts stay in your browser. Nothing is uploaded, and your last inputs are kept in your browser’s local storage so a refresh doesn’t lose your work. Use Clear to remove them.