Code Diff Checker Online
Compare two code snippets and see exactly what changed with syntax-aware highlighting. All processing happens client-side — your code stays on your machine.
What is a code diff?
A code diff visualizes the differences between two versions of source code. Unlike plain text diffs, code diffs are often displayed with syntax highlighting so developers can quickly identify meaningful changes versus whitespace or formatting shifts. Code diffs are the backbone of pull request reviews on platforms like GitHub and GitLab.
Common use cases
Developers use code diffs to review pull requests, debug regressions by comparing working and broken versions, verify refactoring didn't change behavior, and audit third-party dependency updates. Code diffs are also useful when merging branches or resolving conflicts in version control.
Frequently Asked Questions
Can I compare code in any programming language?
Yes. The diff engine works on any plain-text content regardless of language. The comparison is character- and line-based, so it supports JavaScript, Python, Java, Go, SQL, and any other language.
Does the code diff ignore whitespace changes?
By default all changes are shown, including whitespace. You can use the tool's options to toggle whitespace-insensitive comparison if you only care about meaningful code changes.