diff-checker

Paste two versions of text, config, or code and see a line-by-line diff — additions, removals, and unchanged context. Everything stays in your browser.

client-side only line-based diff no signup
original
changed

// how this compares text

This runs a line-based diff (similar in spirit to what git diff shows) — it finds the longest matching sequence of unchanged lines between the two versions, and treats everything else as added or removed. It's a whole-line comparison, not a character-by-character one, so a single-character change on a line marks that entire line as changed rather than highlighting just the character.

// when this is the right tool

For anything larger than a quick check — a full file or a real pull request — your editor's built-in diff view or git diff will handle whitespace, renames, and large files far better than a browser textarea.