Sovryn is a non-custodial and permission-less smart contract based system for bitcoin lending, borrowing and margin trading. Sovryn provides FastBTC Relay which allows use of Bitcoin with smart contracts and decentralized products, from any Bitcoin wallet. Sovryn uses RSK, which is a Bitcoin layer 2 smart contract protocol. Sovryn requires at least one confirmation for all FastBTC relay transactions. For very large transactions, it requires more confirmations on a risk-adjusted basis.
The FastBTC relay is currently centralized. They claim to change this soon as they add a federation and then further steps to decentralize it. There are also plans to link it with a lightning network, so that transfers can happen instantaneously in the future.