Diffchecker

Compare text files and find differences between two texts with advanced highlighting and comparison options

Original Text
Changed Text

What is a Diffchecker?

A Diffchecker is a tool that compares two pieces of text and highlights the differences between them. It's commonly used by developers, writers, and content creators to track changes, compare versions, and identify modifications in documents or code.

Our diffchecker provides side-by-side comparison with color-coded highlighting to make it easy to spot additions, deletions, and modifications between two texts.

Example Use Case:

Original:  "version": "1.0.0"
Changed:   "version": "1.0.1"

Result: Shows character-level highlighting of "0" → "1"

Perfect for comparing code files, configuration files, documentation, or any text-based content.

Why Prettify Code Diffchecker?

There are many diff tools available — but Prettify Code's diffchecker is designed with modern developers in mind:

  • Advanced Algorithm – Uses intelligent similarity detection for accurate comparisons
  • Character-Level Highlighting – See exactly what changed within each line
  • Client-Side & Secure – Your data never leaves your device
  • Side-by-Side View – Clear visual comparison with synchronized scrolling
  • One-Click Copy – Copy original or changed text instantly
  • PDF Export – Generate professional reports for documentation and sharing
  • Dark & Light Mode – Comfortable viewing in any environment
  • No Ads or Clutter – Focus on your comparison, not distractions
  • Mobile-Optimized – Compare text on any device
  • Part of a Full Dev Toolkit – Explore more tools at prettifycode.com

Key Features

  • Smart Diff Algorithm – Uses Longest Common Subsequence (LCS) with similarity detection to accurately identify modifications vs separate changes
  • Character-Level Highlighting – See exactly which characters were added, removed, or modified within each line with GitHub-style highlighting
  • Visual Statistics – Get instant feedback on the number of additions and removals with clear counters in each panel
  • Synchronized Scrolling – Both panels scroll together automatically, making it easy to compare large files line by line
  • Easy Copy & Paste – One-click copy buttons for each panel, plus full text selection support for partial copying
  • Text Swapping – Quickly swap original and changed text to reverse the comparison direction
  • PDF Export – Generate professional PDF reports with side-by-side comparison, color-coded differences, and summary statistics

Common Use Cases

  • Code Review – Compare different versions of source code to identify changes and improvements before merging
  • Document Editing – Track changes in documents, contracts, or any text-based content between revisions
  • Configuration Files – Compare configuration files to identify differences in settings between environments
  • Data Validation – Verify data integrity by comparing datasets, API responses, or exported files
  • Content Migration – Compare content before and after migration to ensure nothing was lost or changed unexpectedly
  • Debugging – Compare working vs broken code, logs, or output to identify what changed and caused issues

How to Use Diffchecker

  • Paste or type your original text in the left panel
  • Paste or type your changed text in the right panel
  • Click "Find Difference" to compare the texts
  • View highlighted differences with color-coded additions and removals
  • Use copy buttons to copy either version of the text
  • Click "Export to PDF" to generate a professional report (optional)
  • Click "Edit" to return to editing mode and make changes
  • Use "Swap" to reverse the comparison direction
  • Click "Clear" to start fresh with new content

Pro Tip

Use line breaks to make differences more visible in the comparison. When comparing code, copy and paste directly from your text editor or IDE for best results.

Character highlighting shows exactly what changed within modified lines, while the swap function lets you quickly reverse the comparison direction to see changes from different perspectives.

Diffchecker FAQs

Common questions about our text comparison tool

How accurate is the diff algorithm?

Our diffchecker uses the Longest Common Subsequence (LCS) algorithm with similarity detection, the same approach used by professional tools like Git and VS Code. It accurately identifies modifications vs separate additions/deletions.

Can I compare large text files?

Yes! Our tool handles large text files efficiently. The interface automatically adjusts height and provides synchronized scrolling for easy navigation through long documents.

Is this diff tool free to use?

Yes, our Diffchecker is completely free to use with no limitations on file size or number of comparisons. No registration or login required.

What's the difference between character and line highlighting?

Line highlighting shows which entire lines were added (green) or removed (red). Character highlighting shows exactly which characters within a line were changed, perfect for spotting small modifications.

Can I use this for code comparison?

Absolutely! Our diffchecker is perfect for comparing code files, configuration files, JSON, XML, or any text-based content. The monospace font and syntax-aware highlighting make it ideal for developers.

How do I copy the results?

Use the copy buttons in each panel header for one-click copying, or select any portion of text directly from the diff view. Both methods preserve the original formatting.

Why do some lines show as modifications instead of separate changes?

Our smart algorithm detects when lines are similar (greater than 50% similarity) and treats them as modifications rather than separate deletions and additions. This provides more accurate and meaningful comparisons.

Is my data secure when using this tool?

Yes! All text comparison happens entirely in your browser. Your data never leaves your device or gets sent to any server, ensuring complete privacy and security.

Can I export the differences to PDF?

Yes! After finding differences, click the "Export to PDF" button to generate a professional PDF report with side-by-side comparison, color-coded differences, and summary statistics. Perfect for documentation or sharing results.