Free Diff Checker Online
Compare two texts and highlight differences line by line. Free, fast, and works entirely in your browser with no sign-up required.
Diff Checker
Compare two texts and highlight the differences with syntax highlighting, multiple view modes, and export options.
Compare Options
Compare Two Texts
Paste text into the panels above, upload files, drag and drop, or click "Load Sample" to see the diff checker in action.
About Diff Checker
- • Green highlights added content
- • Red highlights removed content
- • Amber/Yellow highlights modified lines
- • Side-by-side and unified view modes
- • Line, word, and character-level comparison
- • Inline word-level diff within modified lines
- • Syntax highlighting for 18+ languages
- • Auto-detects programming language
- • Ignore whitespace, case, blank lines, comments
- • Upload files or drag and drop to compare
- • Export as unified diff, patch, HTML, or JSON
- • Fold/collapse unchanged regions
- • Save comparisons to history (localStorage)
- • Change overview minimap for quick scanning
- • Keyboard shortcuts: Alt+Up/Down, Shift+?
- • Search within diff results with match count
- • Visual breakdown bar of change statistics
- • Share comparisons via URL
Frequently Asked Questions
What is the Diff Checker?
The Diff Checker is a free online tool that compares two pieces of text or code and highlights differences line by line for easy review.
Is the Diff Checker free?
Yes, it is completely free with no registration required. All comparison happens client-side in your browser.
Does it store my code?
No, all comparison happens locally in your browser. Your code and text are never sent to any server.
Does the Diff Checker work on mobile devices?
Yes, the Diff Checker is fully responsive and works on smartphones and tablets. You can use it on any device with a modern web browser -- no app download required.
Do I need to create an account to use this tool?
No account or registration is needed. Simply open the Diff Checker in your browser and start using it immediately. There are no sign-up walls or usage restrictions.
How do I use the Diff Checker?
Simply enter your input in the provided field, adjust any settings to your preference, and the tool will process it instantly. You can then copy the result to your clipboard or download it.
Which browsers are supported?
The Diff Checker works in all modern browsers including Chrome, Firefox, Safari, Edge, and Opera. For the best experience, use the latest version of your preferred browser.
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About Free Diff Checker Online
Free Diff Checker Online is a free, browser-based tool in our Code Tools collection. Everything runs locally on your device — no uploads, no sign-up, and your data stays private.