You would typically integrate with a gateway who integrates with one or more banks who integrate with the schemes to get global coverage. There are generally a

You would typically integrate with a gateway who integrates with one or more banks who integrate with the schemes to get global coverage. There are generally a number of domestic gateways in each region (I’ve worked with gateways in Australia, Malaysia and a couple of other places) but there are also larger providers. There are name brands like Braintree and lesser known but still quite large, like Adyen. The API quality is extremely variable. Checking out multiple gateways is a good idea. Stripe is supposed to be great but IIRC is relatively expensive.