Text Diff Checker

About This Free Online Text Diff Checker

Our free online Text Diff Checker compares two blocks of text and highlights every difference. See added lines in green, removed lines in red, and changed lines in yellow — just like a professional diff tool. Perfect for reviewing document changes, comparing code versions, checking edits, or verifying text before and after processing. Line-by-line comparison makes it easy to spot exactly what changed. All processing is done in your browser for complete privacy.

Features of Our Text Diff Checker

Line-by-line diff comparison
Added lines highlighted in green
Removed lines highlighted in red
Changed lines highlighted in yellow
Word-level highlights within changed lines
Copy both versions easily
100% private — browser-only processing

How to Use the Text Diff Checker

The Text Diff Checker works right in your browser — no signup, no installation. Follow these steps:

Paste the original text into the left textarea.
Paste the modified text into the right textarea.
View the diff result with color-coded changes.
Use the action buttons to copy either version.

Frequently Asked Questions About Text Diff Checker

How does the diff algorithm work?

The tool uses a line-by-line Longest Common Subsequence (LCS) algorithm for accurate diff output. Lines are classified as added, removed, unchanged, or changed.

Can I diff code with this tool?

Yes. The tool works with any text including code, making it useful for reviewing code changes and pull request diffs.

Is my text sent to any server?

No. All diff computation happens entirely in your browser. Nothing is uploaded or stored externally.

Why Choose the Text Diff Checker?

Bulk text edits that would take ages by hand happen in one step with the Text Diff Checker. It applies your changes the moment you make them, entirely in the browser, so your content stays on your device and the result is ready to copy immediately.