Code Diff Checker

Compare two code snippets side by side and highlight every difference. Supports 20+ programming languages with side-by-side and unified diff views, line numbers, and patch export.

How to Use Code Diff Checker

  1. 1

    Paste Your Code

    Paste the original code in the left panel and the modified code in the right panel.
  2. 2

    Choose a View Mode

    Select side-by-side view to see both versions in parallel columns, or unified view for a single-column diff with +/- prefixes.
  3. 3

    Review the Differences

    Additions are highlighted in green and deletions in red. The summary bar shows counts of additions, deletions, and unchanged lines.
  4. 4

    Export or Share

    Click Export .patch to download a standard patch file, or use Copy Diff to copy the results to your clipboard.

Why Use a Code Diff Checker?

Code diff checkers are essential for developers who need to quickly compare two versions of source code. Whether you are reviewing pull requests, debugging regressions, or comparing different implementations, a visual diff tool saves time and reduces errors. Unlike generic text diff tools, our Code Diff Checker is built specifically for code. It understands programming language context, provides proper line numbering, and offers both side-by-side and unified diff views that developers expect from tools like GitHub and GitLab. The tool runs entirely in your browser with no server uploads, making it safe for proprietary code. Export your diff as a .patch file to share with teammates or attach to code reviews.

The Code Diff Checker is a free online tool for comparing two code snippets and visualizing every difference. Built specifically for developers, it provides GitHub-style side-by-side and unified diff views with line numbers, addition/deletion highlighting, and diff statistics.

All processing happens in your browser. No code is uploaded to any server, making this tool safe for proprietary codebases. Export your diff as a .patch file for code reviews and collaboration.

How It Compares

While our Diff Checker handles general text comparison and JSON Diff provides semantic JSON diffing, the Code Diff Checker is purpose-built for source code with programming language support, line numbering, and developer-friendly export options.

Frequently Asked Questions

1

What programming languages does this code diff tool support?

The Code Diff Checker supports 20+ languages including JavaScript, TypeScript, Python, Java, C#, C++, Go, Rust, Ruby, PHP, Swift, Kotlin, HTML, CSS, SQL, Shell/Bash, YAML, JSON, XML, and Markdown. Language selection helps with display but the diff algorithm works with any text-based code.
2

Is my code uploaded to any server?

No. All comparison happens locally in your browser. Your code never leaves your device, making this tool safe for proprietary and sensitive source code.
3

What is the difference between side-by-side and unified diff views?

Side-by-side view shows the original and modified code in parallel columns, making it easy to see changes in context. Unified view shows all changes in a single column with + and - prefixes, similar to git diff output. Choose whichever view works best for your workflow.
4

Can I export the diff results?

Yes. Click the Export .patch button to download the diff as a standard patch file that can be shared with teammates or applied using git apply.
5

How does the ignore whitespace option work?

When enabled, the tool normalizes all whitespace (spaces, tabs, multiple spaces) to single spaces before comparing. This is useful when comparing code that may have different indentation styles or trailing whitespace.

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