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Text Diff / Compare

Compare two blocks of text side-by-side with color-coded additions, deletions, and modifications. Supports character-level and line-level diff for contracts, code, logs, and JSON.

Why Use Text Diff / Compare?

When a client emails you "v3-FINAL-revised.docx" after you've already implemented "v3-FINAL", hand-scanning the two is slow and error-prone. A diff tool highlights the three words they actually changed in seconds. Developers use it the same way for quick contract, config, or markdown comparisons when a full Git workflow is overkill — think comparing two .env files, two error logs, or two API response bodies that supposedly differ by one field. Because it runs client-side, you can diff legal documents or customer data without uploading them anywhere.

How to Use Text Diff / Compare

  1. Paste the original text in the left panel and the modified text in the right panel.
  2. Click 'Compare' to instantly highlight the differences between the two texts.
  3. Review the color-coded diff output: green for additions, red for deletions, and unchanged text in the default color.

Worked Examples

Spot the one-word edit in a contract clause

Input
Left: "The Party shall deliver within 30 days."\nRight: "The Party shall deliver within 45 days."
Output
Red: "30" • Green: "45" • Everything else unchanged.

Character-level diff catches tiny edits that line-level would miss.

Compare two error stack traces

Input
Left: production stack trace • Right: local reproduction stack trace
Output
All frames match except one extra middleware call on production

Line-level mode is faster for stack traces since each frame is its own line.

Audit a JSON response for a schema change

Input
Left: yesterday's API response • Right: today's response
Output
Added field "is_beta": true highlighted in green; everything else identical.

Pretty-print both JSON blobs first (use our JSON Formatter) so the diff aligns cleanly.

About Text Diff / Compare

The Text Diff tool lets you compare two pieces of text side-by-side to instantly spot every difference. Whether you're reviewing code changes, comparing document versions, checking translations, or auditing content edits, this tool provides a clear, color-coded visualization of all insertions, deletions, and modifications. It uses the same diff algorithm trusted by professional version control systems like Git. The tool supports character-level and line-level comparison modes, making it suitable for both prose editing and code review. All comparison happens locally in your browser for speed and privacy — your documents never leave your device.

Troubleshooting & Common Issues

The entire document shows as changed — nothing lines up

Check line endings. Text copied from Windows uses `\r\n` and from macOS/Linux uses `\n`; mixed endings cause every line to appear different. Normalize both panes to the same line ending before comparing.

Small edits inside long paragraphs are hard to spot

Switch from line-level to character-level (or word-level) diff mode. Line mode highlights the whole line as changed even if only one word differs, which buries the real edit.

Diff of JSON/XML shows every line changed after a reformat

Different formatters use different indentation (2 vs 4 spaces, tabs vs spaces). Pretty-print both sides with the same formatter before diffing, or use a structural diff tool that compares parsed JSON objects rather than raw strings.

Invisible characters make "identical" text look different

Zero-width spaces, non-breaking spaces, and BOM markers are common when pasting from rich text editors. Paste into a plain-text editor and retype problematic whitespace, or enable "show invisible characters" in your editor to hunt them down.

Frequently Asked Questions

How does the diff comparison work?

The tool uses an advanced longest-common-subsequence algorithm (the same one used in Git) to find the minimal set of changes between two texts. It then highlights additions in green and deletions in red for easy visual review.

Can I compare code files?

Yes! The tool works excellently for comparing code snippets, configuration files, or any structured text. It preserves whitespace and indentation, which is critical for code comparison.

Is there a size limit for text comparison?

The tool can handle large texts efficiently, but for optimal performance we recommend texts under 100,000 characters per panel. Since processing is done in your browser, performance depends on your device's capabilities.

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