I understand that to use the Checkout API my app needs to be a Sales Channel. Does this require special permission from Shopify or is it easily done via the app install process?
I also noticed on this page: https://shopify.dev/tutorials/authenticate-a-public-app-with-oauth that "If your app doesn't meet the requirements to become a sales channel, then you can submit a request to add payment processing to your app." - does that mean it might be possible to gain access to the Checkout API without becoming a Sales Channel? Under what sort of conditions would Shopify provide permission to process payments?