How does the text diff checker work?

It aligns both texts with the longest-common-subsequence algorithm and highlights each line as added, removed or unchanged — with line numbers from both versions.

Is the comparison private?

Yes — everything runs in your browser with no network requests.

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Text Diff Checker

Paste two versions, instantly see what changed — additions in green, removals in red, line by line.

Original text

Changed text

Ignore trailing spaces Ignore case

🔒 Compared in your browser — your text never leaves this page

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Spot every change between two versions

Contracts before and after edits, two drafts of an essay, config files, code snippets, translated copies — whenever you need to know exactly what changed, a diff beats squinting at two windows. This checker uses the longest-common-subsequence algorithm (the same family Git uses) to line up both texts and mark each line as unchanged, added or removed, with original line numbers on both sides. Toggle "ignore trailing spaces" for messy copy-pastes and "ignore case" when capitalization doesn't matter.

FAQ

How large can the texts be?

Precise diffing runs on texts up to ~1,500 changed lines each; beyond that the tool falls back to marking the whole changed block, which is still accurate just less granular. Common prefixes and suffixes are skipped instantly, so long files with small edits are fast.

Is a "changed" line shown as edited?

An edited line appears as its old version removed (red) plus its new version added (green) — the standard unified-diff convention that makes every character difference visible.

Is my text private?

Completely — the comparison runs in your browser with zero network requests. Sensitive contracts and unpublished drafts stay on your machine.

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