What does this tool do
The Text Diff Checker compares two text inputs and highlights changes. Choose word-level or line-level diff. Additions appear in one colour, deletions in another. Useful for reviewing edits, comparing versions, and spotting differences in config or code.
How to use it
- Paste text — Enter or paste the original text in the first area, and the modified text in the second.
- Choose mode — Word-level (highlights changed words) or line-level (whole lines).
- View diff — Changes are highlighted. Additions and deletions are clearly marked.
- Swap — Swap the two inputs to reverse the comparison if needed.
- Copy — Copy the diff output if the tool supports it.
How it works
The tool uses a diff algorithm (e.g. from the diff package) to compute the shortest edit sequence between the two texts. For word-level mode, the text is split into words and diffed; for line-level, it is split into lines. The result is rendered with span elements for added (green) and removed (red) segments. All processing runs client-side.
All computation runs entirely in your browser. No data is sent to any server.
Use cases & examples
- Code review — Compare before/after code changes.
- Configs — Spot differences between config versions.
- Contracts — Compare agreement drafts.
- Translations — Check translation updates.
- Plagiarism — Compare similar documents (manual review).
Example
Original: The quick brown fox
Modified: The fast brown fox jumps
Word diff: "quick" removed, "fast" and "jumps" added.
Limitations & known constraints
- Two inputs only — Cannot compare more than two texts at once.
- Plain text — No syntax highlighting or structured diff for code.
- Large files — Very long texts may slow the diff computation.
- No merge — Shows diff only; no 3-way merge or conflict resolution.