Code Diff Checker

Ignore whitespaceIgnore case

Original Code

Modified Code

How to Use Code Diff Checker

Paste Your Code

Paste the original code in the left panel and the modified code in the right panel.
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.
Review the Differences

Additions are highlighted in green and deletions in red. The summary bar shows counts of additions, deletions, and unchanged lines.
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. On this page, the tool runs in your browser and uploads nothing, which makes 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 an 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.

On this page, all processing happens in your browser and no code is uploaded, which makes it safe for proprietary codebases; the REST API and MCP tool are a separate path, where a call sends the code you include to FindUtils, which compares it without storing it. 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

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.

Is my code uploaded to any server?

Not on this page. All comparison happens locally in your browser, and your code stays on your device, which makes the page safe for proprietary and sensitive source code. The REST API and MCP tool are a separate path: a call sends the input you include to FindUtils over HTTPS, where it is processed and the result returned. FindUtils does not store that input, and logs the request without its content.

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.

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.

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.

Does the Code Diff Checker require a signup?

No. It is available with no signup and no usage limits. On this page, both snippets stay in your browser.

Does it show line numbers?

Yes. Both the side-by-side and the unified views number the lines, so a review comment can point at a line in either version.

Can I share a diff with a teammate?

Export the .patch file and send it, or paste the unified view into a message. There is no hosted share link, because this page never sends your code anywhere.

Run it from code

$ curl -X POST \
  api.findutils.com/api/tools/code-diff-checker/execute \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -d '{"original":"a\nb\nc","modified":"a\nx\nc"}'

$ claude mcp add findutils \
  --transport http https://mcp.findutils.com/ \
  --header "Authorization: Bearer YOUR_API_KEY"
# then call findutils:code_diff_checker

Running a tool needs an API key. Keys are not for sale yet: ask for early access. About API keys

The REST API and the MCP tool are a separate path from this page: a call sends the input you include to FindUtils over HTTPS, where it is processed and the result returned. FindUtils does not store that input, and logs the request without its content.

API reference Add to Claude

How to Use Code Diff Checker

Paste Your Code

Choose a View Mode

Review the Differences

Export or Share