Text Differ

Compare two blocks of text line by line

Original Text

Modified Text

A side-by-side text differ for comparing two versions of code, config, or prose. Paste the original and modified text, run the comparison, and see exactly which lines were added or removed — useful for reviewing changes without opening a full diff tool or version control client.

What diff algorithm does this use?
A line-based longest common subsequence (LCS) comparison, the same family of algorithm behind most code diff tools. It runs entirely in JavaScript in your browser.
Does it compare characters or whole lines?
Lines. Each line in the original is matched against the modified text, and unmatched lines are shown as additions (green) or deletions (red) side by side.
Is there a size limit?
Very large documents fall back to a faster positional comparison instead of the full LCS table, so the tab stays responsive rather than freezing on huge inputs.