Code Diff Viewer
Compare two code files or snippets with syntax-aware highlighting. See exactly what changed between versions in any programming language.
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Review Code Changes Without a Git Client
Code review often happens outside of Git. A colleague sends two versions of a file over email. A student submits an updated assignment. A client provides revised requirements in a code block. You need to see the differences, but you are not in an IDE or repository.
Our code diff viewer gives you the same side-by-side comparison you would see in GitHub or VS Code, right in your browser. Paste two code snippets and every line addition, deletion, and modification is highlighted with syntax awareness. The diff algorithm understands code structure, not just raw text.
It supports all major programming languages with proper syntax highlighting. JavaScript, Python, HTML, CSS, SQL, Java, Go, Rust, and dozens more. Line numbers, collapsible unchanged sections, and a navigation bar make it easy to review even large diffs.
Developer-Grade Code Comparison
Built for how developers actually review code
Syntax Highlighting
Language-aware coloring for 50+ programming languages in the diff view.
Side-by-Side View
Left-right comparison with line numbers and alignment for easy scanning.
Unified Diff Mode
Switch to a single-column unified diff format used in Git and patches.
Collapse Unchanged Code
Hide identical sections to focus only on the lines that changed.
Character-Level Diff
Within changed lines, see exactly which characters were modified.
Copy Diff Output
Copy the diff in unified format for sharing in pull requests or issues.
How to Compare Code
Fast code comparison
Paste Both Versions
Put the original code on the left and the updated code on the right.
Select Language (Optional)
Choose the programming language for proper syntax highlighting.
Review the Diff
Scan highlighted changes line by line. Export or copy when done.