Text Diff Checker

Paste two versions of a text or code block to see exactly which lines were added or removed. Comparison runs locally — nothing is uploaded.

How this diff checker works

The tool compares your two texts line by line using a longest-common-subsequence algorithm — the same family of algorithm used by tools like diff and Git. Lines that only exist in the "Changed text" box are highlighted green with a + marker; lines that only exist in the "Original text" box are highlighted red with a - marker; unchanged lines are shown dimmed with no marker.

When to use a diff checker

Comparing two versions of a config file, a paragraph of copy, a CSV export, or a code snippet by eye is slow and error-prone — it's easy to miss a single changed character in a long line. A line-based diff makes changes obvious at a glance, which is why the same technique underlies code review tools and version control systems.