Snappy Checkout does have an API (just some basic calls right now) & webhooks that can help with digital fulfillment. For my own business, a webhook notifies me of a new sale and I use the Snappy Checkout API to verify that the sale is legit -- which basically allows me to verify that the paid price matches the expected product price.

If you meant non digital fulfillment, I don't know much about that. I'm interested in improving Snappy Checkout to help in that area if at all possible.