Diff Checker: Compare Text Online
Compare two versions of text, code or JSON and see exactly what changed, line by line and word by word. The comparison runs in your browser, so nothing is uploaded, with no size limit or sign-up.
How to use Diff Checker
- Paste the original text on the left and the changed text on the right, or drop two files on the page.
- Choose Side by side or Unified view.
- Tick Ignore whitespace, Ignore case or JSON (ignore key order) if those differences don't matter, and Hide unchanged to fold the lines that match.
- Jump between changes with the arrows, and use Copy patch or download a .diff file.
Frequently asked questions
How do I compare two text files online?
Paste each version into one side, or drop both files anywhere on the page. Changed lines are highlighted, and the words that differ within a line are marked.
What do the colours mean?
Red lines were removed from the original and green lines were added in the changed version. A darker highlight inside a line marks the exact words that changed.
Can I compare JSON while ignoring key order?
Yes. Tick JSON (ignore key order) and both sides are pretty-printed with sorted keys first, so only real changes in values show up. To check or format a single document, use the JSON formatter.
Can I export the differences as a patch?
Yes. Copy patch gives a standard unified diff, the same format as diff -u, which works with git apply or patch.
Is the text I compare kept private?
Yes. The comparison runs in your browser. Inputs are remembered in your browser's local storage so they survive a reload, and are not sent anywhere.
Uses
- Code review: see what changed between two versions of a function or config file, then copy the patch.
- Documents: compare two drafts of a contract, essay or policy to find edits. For PDF files, use Compare PDF.
- Data: compare two API responses in JSON mode, so reordered keys don't show as changes.
- Logs and output: tick Ignore whitespace to see only the lines that really differ.