Text Diff Checker
Compare two blocks of text and see added, removed and unchanged lines highlighted. Free, instant, and fully in your browser.
- ✓ Runs in your browser — nothing uploaded
- ✓ No sign-up
- ✓ Free, no limits
The quick brown fox− jumps over the lazy dog+ leaps over the lazy dog
This free text diff checker compares two versions of any text and highlights exactly what changed — added lines in green, removed lines in red, unchanged lines in grey. Paste your original on the left and the new version on the right, and the line-by-line comparison updates instantly as you type, with a count of how many lines differ.
It is built for the everyday “what changed?” question: comparing two drafts of an email or contract clause, spotting the difference between two config files, checking what an editor altered in your copy, or reviewing a snippet before and after a change. The comparison works on whole lines, which is how people actually read prose and code changes, and it handles inserted, deleted and moved blocks cleanly.
Everything runs locally in your browser — the two texts you paste are never uploaded, which matters when you are diffing contract language, private notes or unreleased content. Worked example: comparing “jumps over the lazy dog” with “leaps over the lazy dog” marks the first line unchanged and shows the second line removed then re-added with the one-word edit.
Frequently asked questions
How does the diff work?
It compares the two texts line by line and marks each line as added, removed or unchanged, using a standard diffing algorithm. Green lines exist only in the new text, red lines only in the original.
Can I compare code as well as prose?
Yes. The comparison is plain-text and line-based, so it works equally well for source code, config files, CSV data or written text.
Is my text uploaded anywhere?
No. Both texts are compared entirely in your browser and never sent to a server — safe for private or confidential content.