Diff Checker
Compare two texts and see exactly what changed — line by line.
How does the diff checker work?
Paste your original text on the left and the modified version on the right, then click Compare. The tool runs a line-by-line diff using the Longest Common Subsequence (LCS) algorithm — the same method used by Git and most version control systems.
Results are color-coded: green lines were added, red lines were removed, and gray lines are unchanged. Line numbers for both versions appear in the gutter.
What can you use a diff checker for?
- Code review: Spot changes between two versions of a function or config file
- Document editing: See what was added or removed between drafts
- API responses: Compare JSON or XML output across environments
- Configuration management: Audit changes to YAML, TOML, or .env files
- Plagiarism check: Compare two pieces of text for similarity
Is my data private?
Yes. All processing happens locally in your browser using JavaScript. Your text is never sent to any server. This makes it safe for sensitive content like API keys, configuration files, or proprietary code.
Quick Reference
| Color | Meaning | Prefix |
|---|---|---|
| Green | Line was added in modified text | + |
| Red | Line was removed from original | - |
| Gray | Line is unchanged |