Text & Code Diff Checker

Diff Options

Original Text (A)

Your Original Text

Modified Text (B)

Your Modified Text

Free Online Text Comparison & Diff Tool

Compare two blocks of text or files instantly with our powerful diff checker. Highlight additions, deletions, and changes with precision using side-by-side or unified views. Perfect for developers, writers, and anyone who needs to compare text versions quickly and securely.

🔒 100% Private

All processing happens in your browser. No data is ever sent to our servers.

⚡ Real-time

See differences instantly as you type with our real-time comparison feature.

🎯 Precise

Word-level highlighting shows exactly what changed, not just entire lines.

How to Use Our Online Text Compare Tool

Paste Your Text

Copy your original text into the left pane and the new text into the right pane. You can also upload files directly.

Choose Options

Select your preferred view mode (side-by-side or unified), highlight level, and comparison options like ignore whitespace or case.

View Results

Our tool instantly analyzes the two texts and highlights every difference with color-coded indicators and detailed statistics.

Key Features of Our Diff Checker

Side-by-Side & Unified Views

Choose between the classic two-pane view for easy comparison or a unified single-pane view that combines both texts with + and - markers.

Precise Word-Level Highlighting

Don't just see which lines changed—see the exact words and characters that were added, removed, or modified for ultimate clarity.

Total Privacy: 100% Client-Side

Your security is our priority. All text comparison and file analysis happens directly in your browser. No data, text, or files are ever uploaded to our servers.

Intelligent Options

Easily compare code or text without getting bogged down by formatting changes. Our 'Ignore Whitespace' option is perfect for developers.

Support for All Text Files

Compare code (JS, Python, Java, C++), configuration files (JSON, YAML), web files (HTML, CSS), or simple .txt documents with ease.

Real-time Comparison

See differences instantly as you type, providing immediate feedback and making the comparison process feel fast and responsive.

Who Can Benefit from a Diff Tool?

For Developers & Programmers

• Quickly check changes in your source code before a git commit
• Compare different versions of a JSON or XML config file
• Easily create a patch file by reviewing the differences
• Compare API responses or log files

For Writers & Editors

• Compare different drafts of an article or blog post
• See exactly what has been changed by a co-author
• Review editorial changes and suggestions
• Track version history of documents

For Students & Academics

• Check for accidental changes in research papers
• Compare your notes against a classmate's
• Review thesis revisions and feedback
• Compare different versions of academic texts

Frequently Asked Questions

What is a "diff"?

A "diff" (short for difference) is a data comparison function that outputs the differences between two files or blocks of text. It's commonly used in version control systems like Git to show what changed between different versions.

Is this diff checker tool free?

Yes, our online diff checker is completely free to use. There are no hidden costs, subscriptions, or limitations on usage.

Is my data safe and private?

Absolutely. The entire comparison process runs on your own computer, using your browser's built-in power. Your data never leaves your machine, ensuring complete privacy and security.

Can I compare Word documents or PDFs?

Our tool works best with plain text files. To compare a Word or PDF document, you can copy the text from the document and paste it into our tool. For complex formatting, consider converting to plain text first.

What file types are supported?

We support all text-based file types including .txt, .js, .css, .html, .py, .json, .xml, .md, and many more. Any file that contains readable text can be compared.

How accurate is the word-level highlighting?

Our word-level highlighting uses advanced algorithms to identify the exact words and characters that changed. It's highly accurate for most use cases, though very complex changes might show some limitations.

Technical Information

Algorithm

Our diff algorithm uses a line-by-line comparison approach with intelligent matching to identify additions, deletions, and modifications. For word-level highlighting, we use pattern matching to identify specific changes within lines.

Performance

The tool is optimized for real-time performance, capable of processing large text files quickly. All processing happens client-side, so performance depends on your browser's capabilities.

Browser Compatibility

Works with all modern browsers including Chrome, Firefox, Safari, and Edge. Requires JavaScript to be enabled for full functionality.

File Size Limits

While there are no strict limits, very large files (over 1MB) may experience slower performance. For best results, we recommend files under 500KB for optimal speed.

Privacy & Security

Your Data Stays Private

We believe in complete privacy. Our diff checker processes all text and files entirely in your browser. No data is ever transmitted to our servers, ensuring your sensitive information remains completely private.

• No data is uploaded to our servers
• No cookies or tracking of your content
• No storage of your files or text
• All processing happens locally in your browser