One benefit of 21's API billing model is lower transaction fees. If the dev only uses $2 of API fees, using a service like Stripe would eat up 18% of the income

One benefit of 21's API billing model is lower transaction fees. If the dev only uses $2 of API fees, using a service like Stripe would eat up 18% of the income. Another benefit is that when you do net-30 usage based billing, you always have to be concerned that the card might be maxed out or invalid by the time the bill gets charged. With 21, you can be sure that the bill will get paid since the Bitcoin is locked up in escrow until the transaction is processed.