Text Diff Checker

Cmd/Ctrl+Enter saves "Before" to history.

Diff

Paste text in at least one field.

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Paste two blocks of text and see line-by-line differences — additions, removals, and unchanged lines. This compares whole lines (not individual characters or words) using a classic LCS-based diff, sized for pasted snippets rather than huge files.

Frequently asked questions

Is this a character diff or a line diff?
A line diff — each full line is compared as a unit. A single changed word shows its entire line as removed and re-added, not a highlighted word within an unchanged line.
Will it handle very large files (thousands of lines) quickly?
It uses a classic LCS-based dynamic-programming diff, which is fine for typical pasted snippets but is O(n×m) rather than Myers' algorithm — for genuinely huge inputs it'll be noticeably slower than a git diff. This is a paste-box tool, not a replacement for git diff on large files.
Does it ignore whitespace-only changes?
No — a line is only considered unchanged if it matches exactly, so trailing whitespace or indentation changes show as a removed/added pair like any other change.
Is my text uploaded anywhere?
No. Comparison happens locally in your browser tab — nothing is sent to a server.

Read the full guide for this tool →

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