Diff Checker

Compare two blocks of text and see the differences highlighted. Free online diff tool — no upload, runs in your browser.

Online Diff Checker

Compare two blocks of text side by side and instantly see what changed. Works with code, JSON, config files, or any text. Everything runs in your browser.

How to Use

  • Paste your original text on the left and the modified text on the right.
  • Differences are highlighted instantly: red for removed lines, green for added lines.
  • Use the Swap button to reverse the comparison.

Frequently Asked Questions

How does the diff checker work?+
The tool compares two blocks of text line by line and highlights the differences. Green lines are additions (only in the right text), red lines are removals (only in the left text), and white lines are unchanged.
Can I compare code with this tool?+
Yes. The diff checker works with any text including code, JSON, CSV, markdown, configuration files, and more. It preserves whitespace and formatting exactly.
Is my text uploaded to a server?+
No. All comparison happens entirely in your browser. Your text never leaves your device.

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