Writing
Text Diff Checker
Paste an original and a changed version of any text to instantly see a colour-coded, line-level diff. The tool uses an LCS algorithm to align the two inputs, marking added lines in green, removed lines in red, and unchanged lines in grey, with counts of each. Everything runs locally in your browser, so your content never leaves your device.
Examples
Input · One line removed, one added.
Original: apple banana cherry
Output
apple - banana + blueberry cherry
How to use Text Diff Checker
Paste your texts
Add the original text on the left and the changed version on the right.
Review the diff
Lines are colour-coded: green for additions, red for removals, grey for unchanged.
Check the stats
See the count of added, removed, and unchanged lines in the summary.
Why use this tool
Instant line-level comparison with no setup
Clear colour-coded additions and removals
Accurate LCS-based alignment of changes
100% private - runs entirely in your browser
Frequently asked questions
It performs a line-level diff, comparing the two inputs one line at a time using an LCS algorithm.
No. All comparison happens locally in your browser and nothing is sent to a server.
Discussion
Share feedback or ask a question about this tool.
Comments are stored to a moderated queue via the API.