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Text Diff Checker Online — Compare Text Side by Side

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

  1. Paste or drag the original text into the left (Original) textarea
  2. Paste or drag the modified text into the right (Modified) textarea
  3. Click Compare or press Ctrl+Enter to see the differences
  4. Switch between Unified and Split view in the Settings panel
  5. 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.