Diff Checker

Compare two texts side by side or as a unified diff, with added, removed and changed lines.

Runs locally in your browser. Your input is not uploaded.Free, no sign-up

Ignore whitespaceIgnore case

Original

Modified

How to use the Diff Checker

Paste the original text on the left and the changed text on the right, or click Sample.
Differences appear instantly: removed lines in red, added lines in green, and changed lines with the exact words that differ highlighted.
Switch between Side by side, Unified and Patch. Download the patch as a .diff file.
Tick Ignore whitespace or Ignore case to hide formatting-only changes.

Good for

Comparing configuration files between environments, like application.yml in staging and production
Checking what changed between two versions of a JSON response, SQL query or log excerpt
Reviewing a change before committing, or explaining one to a colleague as a patch

Frequently asked questions

Is my text uploaded?

No. The comparison runs in your browser, in a background worker so large files don't freeze the page. Configuration and code never leave your machine.

Why are some identical-looking lines marked as changed?

They usually differ in invisible characters, such as trailing spaces or tabs versus spaces. Tick Ignore whitespace to treat them as equal. Windows (CRLF) and Unix (LF) line endings are always treated as equal.

Can I apply the patch with git?

The patch is a standard unified diff. Save it and apply it with git apply changes.diff or patch -p0, adjusting the file names in the --- and +++ lines to match your files.

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