Text Diff
TextCompare two text blocks line-by-line using the LCS algorithm with inline highlighting to review edits and merge conflicting changes side by side in one view.
Related Tools
About Text Diff
When you have edited a config, are comparing two versions of copy, or checking that a copy-paste matched, eyeballing line by line is slow and error-prone. This tool compares two pieces of text locally in your browser and highlights additions, deletions, and changes line by line so differences stand out instantly. Internally it uses the longest-common-subsequence (LCS) algorithm to find the longest run of unchanged lines, then marks every other line as added or removed around that anchor, with character-level detail inside changed lines. It supports ignoring leading/trailing whitespace, ignoring case, and ignoring blank-line differences, plus side-by-side and inline views with statistics for lines added, removed, and changed. You can set the context line count (default 3) around each change to understand the surrounding scope. Two practical cautions: invisible differences like trailing spaces, indentation, and blank lines are counted as real differences, which is exactly what you want when hunting subtle mismatches; and mixed line endings (CRLF vs LF) will flag nearly every line as changed, so normalize them first. For example, diffing hello world vs hello there highlights the world/there change, ideal for config or copy reviews.
How to Use
- Open the Text Diff tool
- Paste the text to process
- Adjust the output options as needed
- Click the Process button; results appear in real time
- Copy or export the result
Use Cases
- Config compare — Compare config files from two environments to find extra or missing fields fast.
- Copy proofing — Match old and new copy to flag changed sentences and avoid missed edits.
- Code review — Paste two function versions to see which lines changed as a lightweight diff.
- Log comparison — Compare a normal vs. failing run log to isolate the differing lines for debugging.
- Paste check — Confirm text copied from two places is identical, catching hidden character differences.
- Translation proofing — Compare source and translated strings segment by segment to flag missing or mistranslated lines.
FAQ
Is the comparison line-based or character-based?
It highlights differences primarily by line; for changed lines you can clearly see which line moved, making the overall changes easy to scan.
Do spaces and line breaks count as differences?
Yes. Trailing spaces, indentation, and blank-line differences are all detected - exactly what you need to find invisible mismatches.
Do inconsistent line endings affect the result?
Yes. If one side uses CRLF and the other LF, nearly every line shows as changed; normalize line endings first so format noise does not mislead you.
Can it compare very large files?
Small to medium text is smooth; very long text (tens of thousands of lines) slows browser rendering, so compare in chunks or use a local diff tool.
Does it handle CJK text correctly?
Yes. It works at the Unicode level, detecting mixed-script and full-width/half-width differences.
Can I save the diff result?
You can copy the differences to save yourself; the tool keeps no text on any server and clears when you close the page.