The refund address is the field worth filling in

Most order forms ask for a refund address and mark it optional. It is the cheapest insurance in the whole flow.

When it is used

• Your deposit arrives after the quote window has closed.
• You send an amount outside the range the pair accepts.
• The pair stops being available between your deposit and the exchange.

In each case there are coins that need to go somewhere and no obvious place to send them. With a refund address, they go back automatically. Without one, they wait for a person to work out where they belong.

What to use

An address you control on the network you are sending from. If you are sending BTC, the refund address is a BTC address. The sending wallet's own receive address is almost always the right answer.

Swap Heaven checks the shape of what you enter, so a wrong network paste is caught before it matters.