Code Diff Viewer
Compare two pieces of text or code side by side. Highlights added, removed, and unchanged lines with color coding in unified or split view.
Original
Modified
Paste text in both panels to see the differences
Code Diff Viewer
Compare two pieces of text or code side by side. Highlights added, removed, and unchanged lines with color coding in unified or split view.
Features
- Line-by-line diff comparison using the LCS (Longest Common Subsequence) algorithm
- Unified and side-by-side (split) view modes
- Color-coded diff output: green for added, red for removed lines
- Line numbers for both original and modified files
- Copy diff output in standard unified format
- Swap original and modified texts with one click
How to use
- Paste the original text in the left panel and the modified text in the right panel, or click Sample for a demo.
- The diff is computed automatically as you type, highlighting additions and deletions.
- Toggle between Unified and Side by Side views, then copy the diff output if needed.
Tips & Best Practices
- Paste your code directly or use the file upload feature for larger files.
- The tool preserves your original input — you can always go back and modify it.
- Use the output directly in your IDE or build pipeline.
- Check the formatted output for any warnings or validation messages.
- All processing is client-side, making it safe for proprietary code.
FAQ
What algorithm is used for the diff?
The tool uses the Longest Common Subsequence (LCS) algorithm, a standard approach for computing line-by-line differences. It identifies the longest sequence of matching lines and marks everything else as additions or deletions.
Can I compare any kind of text?
Yes. The tool works with any plain text including source code, configuration files, prose, CSV data, and more. It performs a line-by-line comparison regardless of the content type.
What do the colors mean?
Green lines are additions (present in modified but not original). Red lines are deletions (present in original but not modified). Uncolored lines are unchanged between the two versions.
Is my data sent to a server?
No. All diff computation happens locally in your browser. Your text and code never leave your device, making it safe for proprietary or sensitive content.
What is the difference between unified and split view?
Unified view shows all changes in a single column with + and - prefixes, similar to git diff output. Split view shows the original and modified files side by side for easier visual comparison.
Can I copy the diff output?
Yes. Click the Copy Diff button to copy the unified diff to your clipboard with standard + and - prefixes for added and removed lines.