Text Diff
Text Diff Checker
Paste an original text on the left and the changed version on the right. Added lines are green, removed lines are red — nothing leaves your browser.
Paste text into both boxes to see the diff.
How to use it
- Paste or type the original text into the left box.
- Paste the changed text into the right box.
- Optionally ignore case or whitespace-only differences.
- Scan the diff view or copy the unified patch.
Examples
Contract review
Spot every change between two draft versions of a document.
Config change
Compare a working config file against a broken one.
Blog edits
See exactly what a copy editor added or removed.
About this tool
Uses a classic longest-common-subsequence algorithm to align lines, then labels every non-matching line as an addition or deletion. Best for prose, config files, or short code snippets. For diffing large binary or code files, use your version control system.
FAQ
- How does the diff work?
- The tool splits each side into lines and runs a longest-common-subsequence algorithm to find matching lines. Lines only in the left side are marked removed; lines only in the right are marked added.
- Can I compare code or JSON?
- Yes. Any plain-text works, including code, JSON, CSV, or Markdown. Whitespace and case sensitivity are toggleable so you can ignore trivial differences.
- Does it handle large inputs?
- It handles inputs up to about 5,000 lines per side comfortably. Very large files are refused so the page stays responsive.
- Is the diff word-level or line-level?
- Line-level. That keeps the output easy to scan and predictable. For word-level diffs use a dedicated code review tool.
- Is anything sent to a server?
- No. The diff runs entirely in your browser and neither side of the comparison is uploaded or logged.
Privacy
Everything runs locally in your browser. Your input is never uploaded, logged, or stored.