Free Tool
Diff Checker
Compare two text blocks and see exactly which lines were added, removed, or unchanged. Works for code, JSON, config files, and plain text.
Diff Checker
What is a diff?
A diff shows the differences between two versions of text. Added lines are highlighted in green, removed lines in red, and unchanged lines in neutral.
How to use
- Paste the original text in the left panel.
- Paste the changed text in the right panel.
- Click Compare — the diff appears with colour-coded changes.
- Click Copy diff to copy the result.
Your text stays in your browser — nothing is sent to any server.
Frequently Asked Questions
- What input types work?
- Any plain text — source code, JSON, Markdown, config files, prose. The tool does a line-by-line comparison.
- Can I compare large files?
- Yes. Processing is done in your browser. Very large files (>1 MB) may take a moment.