Welcome to diffchecker.dev — a fast, secure, and fully client-side online diff checker. Compare text, code, JSON, or XML instantly with no uploads and no sign-in. All diff comparisons run in your browser, ensuring complete privacy for sensitive files, configuration snippets, or code reviews.
Why choose this text & code difference checker?
Most diff tools show basic line changes. This tool is built for developers, writers, and anyone who needs an accurate, private, and high-performance text difference checker. Here is what makes diffchecker.dev unique:
- Instant Comparison (Real-Time Diff): See differences as you type. Everything runs locally using optimized JavaScript diff algorithms.
- Character-Level Granularity: Spot subtle code or text changes—missing braces, whitespace mistakes, renamed variables, or misplaced characters.
- Merge Changes Seamlessly: Choose differences from the left or right panel and create a clean, merged output. Ideal for code reviews or rewriting documents.
- Handles Large Files (25k+ lines): Unlike many tools that freeze or crash, our diff engine is optimized for large content. Use context controls to collapse unchanged lines and focus on what matters.
- JSON, XML, YAML Friendly: Perfect for comparing structured data, API responses, configuration files, or code-related changes.
- No Server Uploads — Ever: Your text stays on your device. This is the most secure way to compare text online.
- Save Diffs Locally: Store your most-used comparisons in browser storage for quick access later.
100% Private, Secure & Client-Side Only
Data security is essential—especially when comparing source code, credentials, or business documents. diffchecker.dev performs all operations locally in your browser. Nothing is uploaded or stored on any server.
How does the Share feature stay secure?
When you create a shareable link, your text is compressed and encoded directly inside the URL. We never store your data on a backend or database. The link itself contains the diff—making it both shareable and private.
How to compare text or code online?
- Paste Original: Enter your original text or code in the left panel.
- Paste Modified: Enter the updated version in the right panel.
- Review Differences: Red shows deletions; green shows additions.
- Merge (Optional): Use arrows to apply changes and copy the final output.
Is this diff checker free?
Yes — diffchecker.dev is 100% free for both personal and commercial use. You can perform unlimited comparisons and merges.