ToolFeather

Text Diff Checker

Paste an original and a changed version to compare them line by line — added, removed and unchanged lines are marked clearly.

Text Diff Checker

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Removed
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🔒 Nothing you enter is sent anywhere or stored. All processing happens in your browser.








  
How it works

  
A diff checker shows exactly what changed between two versions of a text. Paste the original on the left and the edited version on the right, and the tool lines them up and marks every difference.


Lines that appear only in the changed version are shown in green with a + prefix; lines that were removed appear in red with a −; and lines present in both are dimmed with a leading space. The comparison uses a longest-common-subsequence algorithm, so it keeps matching lines aligned even when text is inserted or deleted in the middle. Summary counts at the top tell you how many lines were added, removed and left unchanged.


The whole comparison runs in your browser, which makes it safe for comparing drafts, contracts or code without uploading either version.





  
Examples

  

Two contract drafts → spot every added or deleted clause at a glance.


Before and after a code refactor → see which lines actually changed.


Edited article → confirm only the intended sentences were touched.









Frequently asked questions
Does it compare word by word or line by line?
It compares line by line. Each line is treated as a whole unit, which keeps the output clean and easy to scan for most documents and code.
What do the colours and symbols mean?
Green with a '+' means the line was added, red with a '−' means it was removed, and dimmed lines with a leading space are unchanged in both versions.
How does it align the two texts?
It uses a longest-common-subsequence algorithm, the same core technique behind tools like git diff, so matching lines stay aligned around the changes.
Can I compare code or config files?
Yes. Paste each version into a box. Because it is line-based and runs locally, it works well for source code, configuration and any plain text.
Is my text uploaded?
No. Both versions are compared entirely in your browser and never sent anywhere.