A diff checker is a utility that compares two blocks of text or files to discover differences. It highlights lines and words that have been added, deleted, or modified between the two inputs.

Split view displays the original text on the left and the modified text on the right side-by-side, aligning matching sections. Unified view displays all changes inline in a single scrollable column, overlaying additions and deletions in place.

When a line is detected as modified, the engine splits both lines into individual characters or words and runs a secondary comparison. It highlights characters that are inserted or deleted inside the modified block, saving you from reading line-by-line.

Yes. Your text comparisons are processed entirely inside your local browser using client-side JavaScript. No data is sent to a server, ensuring that confidential notes, source code, and drafts remain completely private.

Yes. The diff checker works with all text formats, including HTML, CSS, JavaScript, Python, JSON, and standard markdown. It preserves indentation, newlines, and spaces.