Advanced Diff Checker
Compare files, identify differences, and merge changes with ease
✓ Runs 100% in your browser — no data sent to serversFrequently Asked Questions
What is a diff checker?
A diff checker (difference checker) is a tool that compares two text files or code snippets and highlights the differences between them. It shows added lines, removed lines, and modified content in an easy-to-read format.
How do I use the merge feature?
After comparing files, you can click on individual lines to select which version to keep, or use "Accept All Left" or "Accept All Right" to choose all changes from one side. The merged result can be copied or downloaded.
What file types can I compare?
You can compare any text-based files including source code (JavaScript, Python, Java, etc.), configuration files (JSON, YAML, XML), markdown, plain text, CSV, and more. Binary files are not supported.
Is my data safe?
Yes, absolutely safe. This diff checker runs 100% in your browser using JavaScript. Your files never leave your computer or get sent to any server. Everything is processed locally on your device.
Can I compare large files?
Yes, this tool can handle files up to several megabytes in size. Since it runs in your browser, the limit depends on your device's memory. For extremely large files (10MB+), you may experience slower performance.
What's the difference between added, removed, and modified?
Added lines (green) exist in the modified file but not in the original. Removed lines (red) exist in the original but not in the modified file. Modified lines (yellow) exist in both but with different content.