ToolWren › Text Diff

Text Diff Checker

Paste two versions of text to see exactly what changed. Added lines are highlighted in green and removed lines in red, with a quick summary.

100% client-side · nothing is uploaded

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How to use the Text Diff

Paste the original text on the left and the changed text on the right.
Differences are highlighted automatically — green for additions, red for removals.
Read the summary line for the count of added and removed lines.
Edit either side to re-compare instantly.

Privacy: this tool runs entirely in your browser. Your input is never sent to, received by, or stored on any server — there are no uploads and no tracking of what you enter.

About Text Diff

Line-by-line comparison

The tool uses a longest-common-subsequence algorithm to align the two texts, then marks each line as unchanged, added or removed — the same approach behind code review diffs.

When to use it

Compare two drafts of an article, two config files, or two versions of code to spot exactly what's different without reading every line.

Privacy

Both texts stay in your browser. Nothing is uploaded, so it's safe for confidential documents.

Frequently asked questions

Does it compare word by word?

It compares line by line, which is the most useful granularity for documents and code.

Is there a size limit?

No hard limit — it handles large texts, bounded only by your device's memory.

Is my text uploaded?

No. The comparison runs entirely in your browser.