I'd like to see if we can integrate an existing system into Shopify, using the tools that came out with Shopify's Subscription APIs.
Our current system does this (without Shopify):
- Asks customers to input their payment method in advance
- Sends the customer offers - Charges the customer -- without exposing them to checkout again -- if they elect to purchase the offer. They just see an offer, basically say "I want that", and then we run a transaction for them.
Is this possible using Shopify for all of the transactions? I see that customerPaymentMethod stores customer payment methods on file and that the Subscription APIs charge those payment methods after the fact, but I don't see a way for our app to say "Okay, charge this customer $<arbitrary-dollar-amount> now."
While technically this could be done I believe it would go against the guidelines for the subscriptions API. This wouldn't be a clear contract about what a customer is going to pay.
If this is closer to an opportunity to buy scenario you can use our deferred purchase options api but the customer would need to do a checkout for each potential purchase whether they purchase it or not, similar to entering a draw.