https://github.com/lollerfirst/nutshell/tree/lnmarkets

With this feature, you can mint USD-pegged ecash with your LNMarkets account as a back-end. When a user decides to mint ecash, they will be required to pay a Lightning Network invoice equivalent to the US dollar amount in satoshis.

As for redemption, the user provides a Lightning Network invoice, and the minting system fetches the current exchange rate from LNMarkets' futures ticker. It then calculates the corresponding US dollar ecash value for the payment quote.

Error messages are a bit all over the place. The documentation itself is not very clear about them, either. I will work to improve them.