# Swap in (Reverse Submarine Swap)

A swap-in (reverse submarine swap) only happens when we are bridging to an EVM layer for escrow services. Once we are swapped in, the keys of our app (AKA the nsec) is the key for spending the funds into the escrow, and sweeping funds out of escrow upon completion.

How can we get cought out?

- We receive preimage from the paid invoice, but never claim our funds due to closed app

- Preimage that we require to claim the funds is lost
+ Allow input such that user can manually paste preimage if the payment notification event gets lost in nostr

- We pay an invoice without checking it's hash corresponds to preimage we generated

- We overpay fees

- We require relay to broadcast claim, since no EVM funds in claimerAddr on first swap-in

flowchart TD
  SwapIn[Swap In
  amount, sweepToAddr]
  --> ContactBoltz[Contact Boltz for Reverse Submarine Swap:amount, claimAddr, preimageHash]
  ContactBoltz --> SwapDetails[Returns:
  amount, refundAddr, timelock, invoice]
  SwapDetails --> PaymentFlow[Payment Flow
  to: invoice, receiptRequired:False, onCompleteOrClose: next]
  PaymentFlow --> ListenForLockTxnConfirm
  ListenForLockTxnConfirm --> ClaimFunds
  ClaimFunds