What this tool does
It undoes the RFC 4180 field rule. If the text starts and ends with a double quote, the enclosing pair is removed and each doubled quote inside becomes a single one: "He said ""hi""" gives back He said "hi".
If it does not start and end with a quote, it comes back untouched. That is deliberate rather than a gap: an unquoted field is already its own value, and a""b with no enclosing pair means a literal a""b, because the doubling rule only applies inside a quoted field.
When you need it
Reading a raw CSV line by eye, or checking what a spreadsheet actually stored in a cell that shows up full of quotes. It is also the quickest way to confirm that a field was quoted correctly rather than quoted twice.
What it does not do
It handles one field, not a row and not a file. There is no delimiter to choose here: quoting is what the tool reverses, and the delimiter only mattered when deciding to quote in the first place.
Line breaks inside the quoted field are preserved. They are legal CSV — part of the value, not the start of a new record — and they come back as they were.
Private by design
Everything runs locally in your browser with JavaScript. Your data is never uploaded, which makes the tool safe for sensitive content, and it keeps working offline.