Yes, we use standard URI scheme, something like this: steem://sign/transfer/username/amount

You can check how it works in one of my recent posts or test it out live via this demo product I made.

Let me know what you think, I was considering adding our payment module for the next SteemFest. I believe it fits perfectly. You can make predefined tickets based on the ticket type and put them in the stock for multiple usage. The invoices are highly customizable, we can add as much extra fields as needed (email, memo, name, etc.), even the number of products if the person wants to make bulk purchases.

In any case, I always loved your work, hope to meet you in the next SteemFest.