Provide Payments supports a suite of peer-audited, open-source smart contracts that can be parameterized via a drop-down menu (or programmatically) and plugged in to payment channels. This effectively creates immutability for the underlying legal agreement between parties. We are working on curating a variety of these contracts for our library based on common use-cases as well as customer demand. Do you have a business case that is not supported? Let us know.