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Text Diff Checker Online

Original Text

PLAINTEXT1 lines
1

Modified Text

PLAINTEXT1 lines
1

Difference

Enter text to see differences

About the Diff

Compare two texts or code files online and see every addition and deletion highlighted line by line. A free, private diff checker for code review, config changes, and log analysis - everything is compared in your browser.

Comparing two versions of text by eye is slow and error-prone. A proper diff highlights exactly what was added, removed, or changed — essential for reviewing code changes, comparing log files, checking contract or config modifications, and merging content edits.

Paste both versions and see a line-by-line comparison with additions and deletions highlighted side by side. The comparison runs locally in your browser, so sensitive code and documents are never uploaded.

Use cases and examples

Review a colleague's changes when you only have the before and after files - paste both sides and see exactly what moved.

Compare two versions of a config file after an incident to confirm precisely what changed.

Diff log files from two runs to spot the first divergent line - often the exact moment a bug appeared.

How to use

  1. Paste the original text in the left panel.
  2. Paste the changed text in the right panel.
  3. Differences appear instantly — added and removed lines are highlighted.
  4. Use the result to review exactly what changed between versions.

Frequently Asked Questions

Can I compare code from different programming languages? ▾

Yes. The diff is line-based and language-agnostic, so it works for code, configs, logs, JSON, and plain text of any kind.

Does the diff detect moved lines or only additions and deletions? ▾

It highlights added and removed lines. A block moved between the two versions shows as a deletion at the old location and an addition at the new one.

Is this tool free to use? ▾

Yes! This tool is 100% free. No signup, no credit card, no limits. It's part of Formatho's privacy-first developer toolkit.

Is my data safe? Does this tool send data to a server? ▾

Absolutely. This tool runs entirely in your browser. Your data never leaves your device. Zero server-side processing, zero tracking.