Text Diff Checker
Paste two versions of any text and see exactly what changed. Runs entirely in your browser — nothing you paste is ever uploaded.
What can you compare?
DiffLens highlights exactly what changed between two blocks of text — two drafts of an essay, two versions of a config file, two revisions of a contract clause, or any pair of texts you need to compare. Switch between line mode (best for code and paragraph-level edits) and word mode (best for spotting small wording changes within a sentence).
How it works
DiffLens compares your two texts directly in your browser using a standard longest-common-subsequence diff algorithm — the same approach behind most diff tools — so nothing is ever sent to a server. Additions are highlighted in green, removals in red, and unchanged content stays plain.
Frequently asked questions
Is this free to use?
Yes. There's no sign-up and no limit on how many comparisons you run.
Do you store the text I paste in?
No. The comparison runs entirely client-side in your browser. See the privacy policy for details.
What's the difference between line and word mode?
Line mode compares whole lines, good for code, config files, or paragraph-level edits. Word mode compares word by word, better for spotting small wording changes within a sentence.
Is there a size limit?
Very large pastes (roughly over 3000 lines or words per side) are rejected with a message asking you to compare smaller sections, to keep the comparison fast in your browser.