Compare two blocks of text and see exactly which lines were added or removed. The comparison runs locally, so nothing you paste is uploaded. 100% Local
How to Use the Diff Checker
Paste the original text on the left and the changed text on the right. Press Compare and the difference is shown line by line: + for added lines and - for removed ones.
How it works
It aligns lines with a longest-common-subsequence algorithm.
Identical lines are shown unmarked between the changes.
Very large comparisons are refused to keep the page fast.
Features
Line-level added and removed highlighting
Added and removed line counts
Identical lines kept in context
All processing runs locally in your browser. Your text is not uploaded to any server.
Diff output is a tool result — review it before applying any change.