Text Diff Checker Online — Free Tool
Compare two texts side by side and see differences highlighted instantly. Additions, deletions, and changes shown in color. 100% browser-based — your data never leaves your computer.
Why Use a Text Diff Tool?
- Code Reviews: Compare different versions of code
- Content Updates: Track changes in documents and articles
- Data Comparison: Verify data hasn't changed between exports
- Configuration Management: Compare config files across environments
Powerful Diff Features
Unified & Split View
Switch between a Unified view (all lines in a single column with +/- markers) and a Split view (original and modified text side by side) using the Settings panel or sidebar.
Smart Diff Options
- Ignore Whitespace: Normalize whitespace before comparing to focus on meaningful changes
- Ignore Case: Compare text case-insensitively
File Import
Drag and drop text files onto the input areas, or use the Load buttons to open files from your computer. Supports txt, json, js, ts, html, css, csv, xml, yaml, md, and many more formats.
Keyboard Shortcuts
- Ctrl + Enter: Run comparison
- Ctrl + B: Toggle sidebar
Stats at a Glance
After each comparison, see detailed statistics including additions, deletions, unchanged lines, and character-level changes.
Export & Copy
Copy the diff output to your clipboard or download it as a .txt file for sharing or documentation.
How It Works
The diff checker compares text line by line using the Longest Common Subsequence (LCS) algorithm:
- Green highlights show added text (present in new but not old)
- Red highlights show deleted text (present in old but not new)
- Unchanged lines are shown in neutral color
How to Use
- Paste or drag the original text into the left (Original) textarea
- Paste or drag the modified text into the right (Modified) textarea
- Click Compare or press Ctrl+Enter to see the differences
- Switch between Unified and Split view in the Settings panel
- Use the sidebar to access additional actions: import files, swap sides, copy diff, and more
Privacy & Security
All text comparison happens entirely in your browser. Your data never leaves your computer. No server uploads, no tracking, no logins required.