What a diff actually shows you
A line-by-line comparison answers one question precisely: what changed between these two versions? Added lines and removed lines are marked separately, which matters more than it sounds. A line that was edited shows up as one removal plus one addition, because that is what an edit is at the line level.
This is the same model used by version control systems, and it is why a reformatted file produces a huge diff even when nothing meaningful changed — every line moved.
When you reach for it
- Checking what a colleague changed in a document or a configuration file.
- Finding the one altered clause in two versions of a contract.
- Spotting an unwanted modification in a block of code pasted from elsewhere.
- Verifying that an export and its re-import really produced the same data.
Nothing is uploaded, which matters when the text is a contract, a credential file or anything you would not paste into a stranger's server.
Frequently asked questions
Does it compare word by word or line by line?
Line by line. A line with a single changed character appears as one removed line and one added line.
Is there a size limit?
No hard limit, but very large texts slow the browser down since the comparison runs on your machine.
Are my texts sent anywhere?
No. Everything is computed locally in your browser.