About the Text Diff Checker
Paste an original and a revised version to see added, removed and unchanged lines side by side. Useful for reviewing contract edits, proofreading translations or checking generated output against a source.
How to use it
- 1Paste both versionsPut the original text in the left pane and the revised text in the right pane.
- 2Run the comparisonThe checker aligns both texts line by line and colour-codes additions and deletions.
- 3Review and exportScan the highlighted lines, then copy the diff summary into your notes or issue tracker.
Why use this text diff checker?
- Nothing leaves your device. The work happens in your browser tab. There is no upload endpoint in this app, so your files and text cannot be stored, logged or seen by us.
- No upload wait. You skip the round trip to a server entirely. Results are limited by your own CPU, not by network speed or queue size.
- Free, no account, no quotas. No sign-up wall, no watermark, no daily limit. Optional accounts only exist to save favourites and presets across devices.
Frequently asked questions
Is my text safe to use here?
Yes. This tool runs entirely in your browser using JavaScript. Nothing you paste or open is sent to a server, and the page keeps no copy after you close it.
Do I need to create an account?
No. Every tool is fully usable without signing in. An account only adds saved favourites and reusable presets.
Does it work on a phone?
Yes. The interface is mobile-first with large touch targets and a stacked layout, so it works on phones and tablets as well as desktops.
Is the comparison case-sensitive?
The line comparison is case-sensitive by default so that real edits are visible. You can enable “ignore case” if capitalisation changes are not relevant to your review.
Can I compare code files?
Yes. Any plain-text format works, including source code, JSON, CSV and configuration files. Very large inputs are processed line by line to keep the interface responsive.