Code Diff
Compare two pieces of code and highlight additions, deletions, and changes. Supports Unified, Side-by-side, and Inline view modes.
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How to Use
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- 1
Enter Code
Enter or paste code into the "Original" and "Modified" text areas.
- 2
Select View Mode
Choose from Unified (Git diff format), Side-by-side (parallel), or Inline (simple) view mode.
- 3
Review and Copy
Review the highlighted diff and copy it in unified diff format if needed.
View Mode
Original
Modified
Diff Result
About Code Diff
Code Diff visually compares two code or text snippets with three professional view modes: unified (Git diff format showing changes in a single stream), side-by-side (parallel panels for before and after), and inline (simple line-by-line highlighting). Paste code before and after a change to see exactly what was added, removed, or modified — with syntax highlighting that makes structural changes easy to spot. It's ideal for preparing code reviews, debugging deployment regressions, verifying refactoring correctness, and documenting changes in pull request descriptions. A swap button reverses the comparison direction, and results can be copied in unified diff format. All processing runs locally in your browser.
Key Features
- Three diff view modes: Unified, Side-by-side, and Inline
- Line numbers for precise change identification
- Copy diff in Git-compatible unified format
- Real-time diff calculation and display
- Statistics showing added, removed, and unchanged lines
Common Use Cases
- Compare code before and after a refactor for pull request review
- Diff environment config files (nginx.conf, docker-compose.yml) across environments
- Check what changed between two versions of a generated file
- Review SQL migration scripts before running in production
FAQ
How is this different from the text diff tool?
The text diff tool offers character, word, and line comparison modes for general prose. Code Diff focuses on line-based comparison with developer-oriented features: line numbers for precise location, diff statistics (added/removed/unchanged counts), and Git-style unified diff output that you can paste directly into a PR description or ticket.
Is my code sent to any server?
No. All processing happens entirely in your browser using JavaScript. Your code is never transmitted to any server, making it safe to paste sensitive configuration files, internal API keys in example code, or proprietary source code you cannot share externally.
Which programming languages are supported?
Code Diff performs language-agnostic line-by-line comparison, so it works with any language or file format — JavaScript, Python, Go, Rust, SQL, YAML, JSON, Dockerfile, nginx.conf, and plain text. There is no need to select a language; differences are detected purely by line content.
What does the unified diff output look like?
Unified diff is the standard format used by Git and most version control systems. Lines starting with + were added, lines starting with - were removed, and lines without a prefix are unchanged context. You can copy this output and paste it directly into GitHub PR descriptions, Jira tickets, or email threads to communicate exactly what changed.
When should I use side-by-side vs unified view?
Side-by-side view is easier to read when changes are scattered across a file, because you can scan the original and modified versions in parallel without losing context. Unified view is more compact and matches what you see in Git terminals and code review tools — better for copying and sharing. Inline view is the simplest, coloring each changed line without the two-panel layout.
Can I use this to compare configuration files?
Absolutely. Code Diff works on any text content, not just source code. It is particularly useful for comparing environment-specific config files (staging vs production nginx.conf), lock files (package-lock.json before and after npm install), or database migration scripts you want to review before applying.