Text Diff Checker
Compare two texts and find differences
How to use
- Paste original text in the left panel
- Paste modified text in the right panel
- View differences highlighted below
Use cases
- Code review
- Document comparison
- Version control
- Content editing
About the Text Diff Checker
A text diff checker shows the difference between two versions of any text — code, prose, JSON, logs, contracts — by identifying which lines were added, removed, or kept. Instead of reading both documents end-to-end, you see only what changed, which is how engineers review pull requests and editors review revisions. This tool runs fully client-side using a longest-common-subsequence algorithm, so your content never leaves the browser.
Features
- LCS-based line diff — shows real insertions and deletions, not just pairwise changes
- +/− change counts per diff
- CRLF / LF normalized automatically
- Copy unified patch for use in git or code review
- Handles 8,000+ line documents
How it works
- Paste the original version into the left panel.
- Paste the modified version into the right panel.
- Changes are highlighted instantly: green for additions, red for removals, neutral for unchanged lines.
- Use 'Copy Patch' to grab a unified-diff output for code review or changelogs.
Frequently asked questions
What is a text diff?
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A text diff is a visual comparison between two versions of text that shows what was added, removed, or left unchanged. It's the same concept git uses in pull requests.
Is my text sent to a server?
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No. All comparison runs entirely in your browser. Nothing is uploaded, logged, or stored.
Can I compare long documents?
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Yes — the tool comfortably handles documents up to around 8,000 lines combined before falling back to a pairwise view.
Does it work with non-English text?
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Yes. Unicode is handled correctly, including CJK, Arabic, and emoji.
Can I export the diff?
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Yes — click 'Copy Patch' to copy a unified-diff style output you can paste anywhere.