Souus Tools
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Text Diff Viewer & Comparator

Free online diff viewer to compare two texts side by side or in unified format, highlighting additions, deletions, and changes instantly.

+6 added-2 removed
- function hello() { console.log("hello");
+ function hello(name) { console.log("hello", name);
return true;
+ } function goodbye() { console.log("bye");
}

AI developer workflow fit

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What Is a Diff Viewer?

A diff viewer is a tool that compares two blocks of text and visually highlights the differences between them. It identifies lines that have been added, removed, or modified, making it easy to review changes at a glance. Diff tools are fundamental in software development for code reviews, merge conflict resolution, and tracking document revisions. This tool supports both side-by-side and unified diff formats, with the output generated entirely in your browser.

How to Use the Diff Viewer

  1. Paste the original text into the 'Original' textarea on the left.
  2. Paste the modified text into the 'Modified' textarea on the right.
  3. View the color-coded diff below: green for additions, red for deletions.
  4. Use the 'Swap' button to reverse the comparison direction.
  5. Switch between 'Side by Side' and 'Unified' tabs to change the diff format.
  6. Copy the unified diff output using the copy button for use in patches or documentation.

Common Use Cases

  • Code Review — Compare original and modified source code to quickly identify what changed, making it easier to review pull requests or patches.
  • Configuration File Changes — Spot differences between two versions of config files (YAML, JSON, .env) to verify deployments or debug environment issues.
  • Document Revision Tracking — Compare drafts of documents, contracts, or articles to see exactly which sentences or paragraphs were edited.
  • Merge Conflict Resolution — Visualize conflicting changes from different branches to understand what each side modified before resolving the conflict.

FAQ

What diff formats are available?
The tool provides two views: Side by Side shows additions and deletions inline with color coding, and Unified generates a standard unified diff format commonly used in patches and version control systems.
Can I compare binary files or images?
No, this tool is designed for plain text comparison. For binary files or images, use specialized diff tools in your IDE or version control system.
Is my text sent to a server?
No. The comparison is performed entirely in your browser using the 'diff' JavaScript library. Your content never leaves your device.
How does the unified diff output work?
The unified diff format shows context lines (prefixed with a space), additions (prefixed with +), and deletions (prefixed with -), along with line range headers. This format is compatible with tools like git apply and the patch command.

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