Text Diff

Additions and deletions are marked separately, so a rewritten sentence shows as both. Changes are located precisely rather than flagging whole paragraphs, which makes it obvious when the only edit was a single number or a negation.

This is the same idea version control uses to review code, applied to plain prose — and it catches the edits that are easy to miss, like a changed date, a dropped 'not', or an altered figure.

Most online text compare sites send both versions to their server to calculate the difference. For a contract, a config file with secrets in it, or an unpublished draft, that is a real risk for a small convenience. This text compare tool does the whole comparison in your browser tab.

Paste the old version on the left and the new one on the right, or use the Open button on each side to load a file straight from your device, up to 5 MB each. Plain text formats all work: .txt, .md, .csv, .json, .xml, .yaml, .log, HTML, CSS and source code. The result lists every line with numbers on both sides, marks what was added and removed, and counts the changes, with a word wrap toggle for long lines.

The comparison works line by line, which is exactly how code review tools show changes. That makes a little preparation worthwhile. Format both versions the same way first: if one JSON file is minified and the other is pretty-printed, every line will show as changed even when the data is identical.

For prose, the same rule applies at sentence level. Put each sentence on its own line before comparing and a single edited word stands out as one changed line, instead of a whole rewritten paragraph. Watch for invisible differences too. Trailing spaces and Windows versus Unix line endings can make lines that look the same count as different.