Ask HN: How does a good pipeline for selling digital goods look like?

I have been working on a startup that will sell digital goods/services in the EU but also world-wide.

How does a good pipeline look like that handles payment, billing/invoicing, accounting?

Currently, we have thought of:

- Stripe for payment, and

- Xero for invoicing/accounting.

However, we have learnt that VAT calculations are a big issue in the EU - and provided VAT numbers have to be verified.

And we were totally shocked that Xero can only handle very few API calls per minute or month and is not even able to send invoices to customers per API call. So now we also consider of using Mandrill for transactional emails.

It seems like we have to use a dozen services just to be able to sell digital services/goods?

How does your pipeline look like for (frequently) selling digital services/goods? Do we need all these other micro services for VAT calculations, sending transactional emails, etc?