Text Diff
Highlight what changed between two texts.
the quick brown fox−jumps over+leaps overthe lazy dog+and runs away
Runs entirely in your browser — nothing you enter is uploaded or sent to a server.
It compares line by line, so a small edit inside a line shows as a whole line removed and re-added — it's for spotting differences, not for merging changes. Read our full disclaimer.
About this tool
Paste an original and a changed version of any text and this tool highlights the differences line by line, using the classic longest-common-subsequence algorithm — the same idea behind git and code review diffs. Added lines are marked in the accent color, removed lines in red, and unchanged lines stay muted, with a running count of each. Handy for comparing drafts, config files, logs, or copy.
Try it
Change 'jumps over' to 'leaps over' and add a line, and the diff shows one removed line, one changed line's replacement, and the new line marked as added.
How to use
- 1Paste the original text on the left.
- 2Paste the changed text on the right.
- 3Read the combined diff below — additions, removals, and unchanged lines.
- 4Use the counts to see how much changed at a glance.
Features
- Line-by-line diff with added / removed / unchanged highlighting.
- Running counts of additions and removals.
- Handles insertions and deletions, not just replacements.
Frequently asked questions
Does it diff word by word or line by line?
Line by line — it compares whole lines, which is the most useful view for text, config, and logs. A changed line shows as a removed line plus an added line.
Can it handle large blocks of text?
Yes. It compares thousands of lines comfortably; a very large paste just takes a moment longer to render the highlighted result.
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