How to Compare Code and Text with a Diff Checker
Learn how to use a diff checker to compare code, text, and documents. Spot changes instantly for code reviews, version control, and debugging.
Whether you're reviewing a pull request, comparing configs, or debugging API responses, a diff checker highlights exactly what changed. Here's how to use one effectively.
What is a Diff Checker?
A diff checker compares two texts and highlights additions, deletions, and changes. Think of it as "before vs after" for any text—code, JSON, config files, or plain text.
Why Use a Diff Checker?
Code reviews. See what changed in a PR without reading the whole file.
Config debugging. Compare dev vs prod configs to spot the one line that breaks things.
API debugging. Compare API responses before/after a change to trace regressions.
Document versioning. Track changes between drafts without manual side-by-side reading.
How to Use a Diff Checker
- Paste the original — your "before" text in the first box
- Paste the modified — your "after" text in the second box
- View the diff — additions (green), deletions (red), changes highlighted
Our diff checker runs entirely in your browser. No data is sent to any server—perfect for sensitive code or configs.
Diff Checker Tips
Line-by-line vs character-level: Most tools highlight by line. For short strings or single-line JSON, character-level diff can be more precise.
Ignore whitespace: Some diffs let you ignore trailing spaces or indentation changes—useful when only logic changed.
JSON/XML diffs: Specialized diff tools can compare structure, not just raw text, so you see semantic changes.
Copy results: Use "Copy" to share the diff in an issue, PR comment, or with your team.
When to Use a Diff Checker
- Before merging code
- When debugging "it worked yesterday" issues
- Comparing API responses or configs
- Reviewing contract or document changes
Try our free diff checker to compare text and code instantly. No sign-up, no data leaves your browser.