About the Diff Checker
Spotting what changed between two versions of a file by eye is slow and unreliable. This diff checker compares the original on the left with the changed text on the right and highlights removals in amber and additions in green, in the same way as a code review. Compare by lines for code and config, by words for prose, by characters for small strings, or by JSON structure when key order and formatting should be ignored.
Options let you ignore case and whitespace so that reformatting does not drown out real changes. The status line counts added and removed chunks, and the Download button saves a standard unified diff (patch format) that git apply and most editors understand. The Copy button copies that same patch text.
Both texts stay in your browser, which matters when comparing contracts, configuration with secrets, or customer data. To compare two hashes rather than texts, the Checksum Compare tool is quicker; for JSON, the JSON Sorter can normalise key order before a line diff.
How to use
- Paste the original text on the left and the changed text on the right.
- Choose lines, words, characters or JSON, and whether to ignore case or whitespace.
- Read the highlighted differences. Download the patch if you need to apply it.
Common questions
- Which mode should I use?
- Lines for code and configuration, words for prose and documents, characters for short strings such as IDs, JSON for data where formatting and key order do not matter.
- Can I get a patch file?
- Yes. Download saves a unified diff that git apply and patch tools accept.
- Is my text uploaded?
- No. The comparison runs in your browser.
- How large a file can it compare?
- Files of a few thousand lines compare instantly. Very large files work but the highlighted view becomes long; the patch download is still practical.