Code Diff Checker
Compare two code snippets side by side and highlight differences
Original Code
Modified Code
Diff Result
-Enter two code snippets and click Compare to see the differences.
Usage Examples
JavaScript Function
Compare two versions of a JavaScript function to see parameter changes, logic updates and new calculations.
Python Class
Compare Python class definitions to spot new methods, parameter additions and modified return values.
JSON Config
Compare package.json or configuration files to identify version bumps, new dependencies and script changes.
Features
Split & Unified Views
Toggle between side-by-side split view and unified diff view for flexible code comparison
Color-Coded Output
Added lines in green, removed in red, modified in yellow, and unchanged lines in normal style
Language Detection
Auto-detects programming language or choose from 18+ languages including JS, Python, PHP, CSS and more
Privacy First
All processing happens locally in your browser, no code is sent to any server
How to Use?
Paste Your Code
Paste the original code on the left and the modified code on the right. Select a language or use auto-detect.
Set Options & Compare
Choose unified or split view, enable options like ignore case or whitespace, then click Compare.
Review & Copy
Review the color-coded diff output with line numbers and statistics. Copy the result if needed.
Frequently Asked Questions
What is Code Diff Checker?
Paste two code snippets and instantly see what changed. Lines are color-coded: green for additions, red for removals, yellow for modifications. You get line numbers, change statistics, and the option to switch between unified and split views. Supports 18+ languages with auto-detection.
Key Features
Split and unified view modes, syntax-aware language detection for 18+ languages, ignore case and whitespace options, detailed stats showing added, removed, modified, and unchanged line counts, and one-click copy of the diff result. All processing happens client-side.
Common Use Cases
Code reviews are the obvious one. Paste the before and after to see exactly what changed. Also great for comparing config files across environments, checking what a merge did to your code, or verifying that a refactor did not change behavior. Works for any text, not just code.
Tips
Use the ignore whitespace option when comparing code with different formatting. The swap button lets you quickly flip original and modified. Try the example to see how the tool works before pasting your own code.
Privacy
Your code stays in your browser. Nothing is sent to any server, nothing is stored. No accounts, no tracking.