darkfi/doc/src/testnet/atomic-swap.md

Atomic Swaps

In order to do an atomic swap with someone, you will first have to come to consensus on what tokens you wish to swap. For example purposes, let's say you want to swap 40 DARKfZX1utGbz8ZpnvtCH6i46nSDZEEGa5fMnhoubWPq (which is the balance you should have left over after doing the above payment) for your counterparty's 20 AcABG4fnmBuT5vuXV8TLdEV8panhk5SdtBZxCCLqQxyL.

To protect your anonymity from the counterparty, the swap can only send entire coins. To create a smaller coin denomination, send yourself the amount you want to swap. Then check you have a spendable coin to swap with:

$ ./drk wallet --coins

You'll have to initiate the swap and build your half of the swap tx:

$ ./drk otc init -v 40.0:20.0 \
    -t DARKfZX1utGbz8ZpnvtCH6i46nSDZEEGa5fMnhoubWPq:AcABG4fnmBuT5vuXV8TLdEV8panhk5SdtBZxCCLqQxyL \
    > half_swap

Then you can send this half_swap file to your counterparty and they can create the other half by running:

$ ./drk otc join < half_swap > full_swap

They will sign the full_swap file and send it back to you. Finally, to make the swap transaction valid, you need so sign it as well, and broadcast it:

$ ./drk otc sign < full_swap > signed_swap
$ ./drk broadcast < signed_swap

On success, you should see a transaction ID. This transaction will now also be in the mempool, so you should wait again until it's finalized.

After a while you should see the change in balances in your wallet:

$ ./drk wallet --balance

If you see your counterparty's tokens, that means the swap was successful. In case you still see your old tokens, that could mean that the swap transaction has not yet been finalized.