Is the diff stored anywhere?

No. Diffing happens locally with the 'diff' library — neither side of the text leaves your browser.

Line mode shows full lines as add/remove blocks — best for source code, JSON, config files. Word mode highlights individual word changes within a paragraph — best for prose, docs, captions.

What does 'ignore whitespace' do?

In line mode, it treats lines as equal if they differ only by leading/trailing spaces or tabs. Useful when comparing reformatted code.

How big can the inputs be?

Tens of thousands of lines work, but the diff is O(n²) so very large files will get slow. For huge files, prefer 'git diff' or a desktop tool.

Text Diff Viewer

Paste two versions of any text and instantly see what changed — added lines highlighted green, removed lines red, and unchanged context in between. Switch between line-mode (for code, configs, lists) and word-mode (for prose). Ignore-whitespace toggle handles trailing-space and indentation drift. Runs entirely in your browser; pasted text never leaves the page.

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Ignore whitespace

+ 0− 0

OriginalChanged

Diff

No differences detected.

How to use

Paste the original text on the left, the new version on the right.
Choose line-mode for code/configs, word-mode for prose.
Toggle 'ignore whitespace' if formatting changed but content didn't.
Read the inline diff and added / removed counts.

Frequently asked questions

Is the diff stored anywhere?: No. Diffing happens locally with the 'diff' library — neither side of the text leaves your browser.
Word vs line mode?: Line mode shows full lines as add/remove blocks — best for source code, JSON, config files. Word mode highlights individual word changes within a paragraph — best for prose, docs, captions.
What does 'ignore whitespace' do?: In line mode, it treats lines as equal if they differ only by leading/trailing spaces or tabs. Useful when comparing reformatted code.
How big can the inputs be?: Tens of thousands of lines work, but the diff is O(n²) so very large files will get slow. For huge files, prefer 'git diff' or a desktop tool.

Guides on this topic

Regular Expressions in Practice How a regex engine actually scans a string, why anchors and greediness change everything, what catastrophic backtracking is, and the formats you should never try to parse with a pattern.

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