---
title: "Code Diff Checker"
description: "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."
url: https://findutils.com/developers/code-diff-checker/
category: developers
---

# 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.

**Use this tool:** [Code Diff Checker](https://findutils.com/developers/code-diff-checker/)

## Programmatic access

- REST id `code-diff-checker`: POST https://api.findutils.com/api/tools/code-diff-checker/execute (reference: https://findutils.com/api/code-diff-checker/)
- MCP tool `code_diff_checker` on https://mcp.findutils.com (reference: https://findutils.com/mcp/code-diff-checker/)

## 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.

## 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?

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

### 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. 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 the code never leaves your browser.