Oddbean new post about login | logout Check out The zeus integration maybe? It might only be with their pos so that's more for brick and mortar but idk if they've got other integrations?
Just looked into it and it's only for their payment terminals, not a solution for online sales.
Ahh too bad...
Shopify has easy setup with open node or strike https://www.opennode.com/blog/shopify-bitcoin-plugin/