Text Diff Compare Tool

Compare text, code, and documents side-by-side. See differences highlighted with additions, deletions, and similarity statistics.

Original Document
Paste or type your original content
Modified Document
Paste or type your modified content

Free Online Text Diff & Code Comparison Tool

Compare text files, code, JSON, and documents instantly. Our diff tool shows line-by-line differences with visual highlighting, making it easy to spot changes between versions. Perfect for developers reviewing code changes, writers comparing document revisions, and anyone who needs to find differences between text files.

View Modes

Side-by-Side

View both documents side-by-side with additions highlighted in green and deletions in red. Perfect for comparing two versions of the same file.

Unified View

See all changes in a single view with +/- markers, similar to Git diffs. Ideal for reviewing changes in version control.

Raw Diff

Plain text diff output that can be copied and pasted. Great for sharing changes via email or documentation.

How to Use the Diff Tool

  1. Paste your original content in the left text area
  2. Paste your modified content in the right text area
  3. View the differences automatically highlighted below
  4. Choose your view mode: Side-by-Side, Unified, or Raw
  5. Review statistics: See additions, deletions, and similarity percentage
  6. Copy or download the diff output for your records

Features

  • ✓Line-by-line comparison - See exactly which lines changed
  • ✓Multiple view modes - Side-by-side, unified, and raw diff
  • ✓Detailed statistics - Additions, deletions, and similarity percentage
  • ✓Syntax highlighting - Colour-coded additions (green) and deletions (red)
  • ✓Copy to clipboard - One-click copy of diff output
  • ✓Download diff - Export as .diff file
  • ✓Swap documents - Quickly reverse the comparison
  • ✓100% client-side - Your text never leaves your browser

Common Use Cases

Code Review

Compare different versions of source code to review changes before merging. See exactly what was added, removed, or modified in your codebase.

Document Versioning

Track changes between document revisions. Perfect for writers, editors, and content managers who need to see what changed between versions.

Configuration Files

Compare config files (.env, .yml, .json) to spot differences in settings and parameters across environments.

Git Diff Alternative

View diffs outside of Git or version control. Useful for comparing files from different sources or systems.

API Response Comparison

Compare JSON responses from different API versions or endpoints to identify changes in data structure.

Database Schema Changes

Review SQL schema changes before applying migrations. See what tables, columns, or constraints changed.

What is a Diff?

A diff (short for "difference") shows the changes between two versions of text. It's commonly used in software development for code reviews and version control systems like Git. The diff algorithm compares files line-by-line and highlights:

  • Additions (green): Lines that were added in the modified version
  • Deletions (red): Lines that were removed from the original version
  • Unchanged (no highlight): Lines that are identical in both versions

Our tool uses the industry-standard diff algorithm to provide accurate line-by-line comparison, similar to what you'd see in Git, GitHub, or other version control systems.

Diff Statistics Explained

Additions

The number of lines added in the modified document compared to the original. Highlighted in green in the diff view.

Deletions

The number of lines removed from the original document. Highlighted in red in the diff view.

Total Changes

The sum of additions and deletions. This represents the total amount of change between documents.

Similarity Percentage

A measure of how similar the two documents are, calculated as (unchanged lines / total lines) × 100. Higher percentages indicate more similar documents.

Supported File Types

While this is primarily a text-based diff tool, it works with any text format:

  • Source Code: JavaScript, Python, Java, C++, Go, Rust, etc.
  • Markup: HTML, XML, Markdown, LaTeX
  • Data: JSON, YAML, CSV, TOML
  • Config: .env, .ini, .conf files
  • Scripts: Bash, PowerShell, SQL
  • Documents: Plain text, logs, README files

Frequently Asked Questions

How does the diff algorithm work?

Our tool uses the Myers diff algorithm, the same algorithm used by Git and other version control systems. It efficiently finds the minimum set of changes needed to transform one text into another.

Is my data secure?

Yes! All comparisons happen entirely in your browser using JavaScript. Your text is never sent to our servers or any third party. The tool works completely offline once loaded.

Can I compare large files?

Yes, the tool can handle files with thousands of lines. However, very large files (100,000+ lines) may take a few seconds to process depending on your browser and computer performance.

What's the difference between side-by-side and unified view?

Side-by-side shows both documents in parallel columns, making it easy to see corresponding lines. Unified view shows all changes in a single column with +/- markers, similar to Git diff output.

Can I export the diff?

Yes! You can copy the diff to your clipboard or download it as a .diff file. The diff is formatted in the standard unified diff format compatible with Git and patch tools.

Does it work with binary files?

No, this tool is designed for text files only. Binary files (images, PDFs, executables) won't display meaningful comparisons.

How is similarity calculated?

Similarity is calculated as the percentage of unchanged lines compared to the total number of lines in both documents. For example, if 80 out of 100 lines are the same, the similarity is 80%.

Tips for Better Comparisons

  • Preserve formatting: Keep the same indentation and whitespace for more accurate line matching
  • Use consistent line endings: Mixing Windows (CRLF) and Unix (LF) line endings can create false differences
  • Compare similar versions: The diff is most useful when comparing closely related versions
  • Use the swap button: If you pasted documents in the wrong order, use the Swap button to reverse them
  • Try different views: Side-by-side is great for visual comparison, while unified is better for copying

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