Text Diff Checker
Paste two versions of any text — code, config, prose or notes — and see exactly what changed, side-by-side, with added, removed and modified lines highlighted down to the word. Everything compares locally in your browser, so nothing you paste ever leaves your device.
- 🔒 100% private — no uploads
- 🆓 Free, no watermark
- 📱 Works on any device
How to compare text
- 1
Paste both versions
Drop your original text on the left and the changed text on the right — paste it, or load a file. Both sides stay on your device.
- 2
Read the differences
Removed lines are red, added lines green, and modified lines show the exact words that changed. Use side-by-side or unified view, and ↑/↓ to jump between changes.
- 3
Tune the comparison
Toggle “Ignore whitespace” to skip indentation and spacing noise, or “Highlight words” for line-only diffs. Swap sides or copy the changed text in one click.
Why use Text Diff Checker?
100% private
The comparison runs entirely in your browser with JavaScript. Your text is never uploaded, stored or seen by anyone — it works offline once loaded.
Word-level highlighting
Modified lines don’t just light up — the exact words that changed are highlighted, so you find the real edit instead of re-reading the whole line.
Side-by-side or unified
Switch between an aligned two-column view, IntelliJ-style, and a single-column unified diff with added/removed lines inline.
Works on any device
No install and no account. Compare text in any modern browser on Windows, macOS, Linux, Android or iPhone.
Compare code, config or any plain text
A diff checker isn’t only for source code. Compare two drafts of an article, two versions of a contract, JSON or YAML config, log files, CSV exports or translation strings. Anything you can paste as text can be compared line by line, with the changed words pinpointed inside each modified line.
Why a client-side diff matters
Online diff tools usually send your text to a server to compute the difference. If you’re comparing source code, an unreleased document or anything with credentials, that’s a leak waiting to happen. This tool computes the diff in your own browser, so sensitive text never travels anywhere — the same reason it keeps working with your network off.
Frequently asked questions
Is my text uploaded to a server?
No. The comparison runs entirely in your browser. Nothing you paste or load is uploaded, stored or sent anywhere — it even works offline once the page has loaded.
What does the word-level highlighting do?
When a line is modified rather than added or removed, the tool highlights the specific words that differ between the two versions, on top of marking the line as changed. Turn it off with the “Highlight words” toggle for a line-only diff.
Can I ignore whitespace and indentation?
Yes. Turn on “Ignore whitespace” and lines that differ only in spacing, tabs or trailing whitespace are treated as identical — handy when reformatting changed the indentation but not the content.
Is there a size limit?
Very large inputs (a few thousand lines per side) are skipped to keep the browser responsive — trim the text and it compares instantly. For typical files and snippets there’s no practical limit.