Headless e-commerce architecture is based on a headless platform.
That means a CMS that stores, manages and delivers content without a front-end and only via API. With a headless platform, the front end (or the “head”) has been decoupled and removed, leaving only the backend.
Backend Developers use APIs to deliver things like products, blog posts or customer reviews. Front-end developers can get to work on how to present that content using any framework they desire.
With "PWA Support" we refer to the the way we support headless e-commerce with our extensions. The generic architecture of reference that involves a PWA front-end, a Magento 2 back-end and Klarna API looks as follows:
With reference to the general architecture, the Klarna extensions are included in Magento 2 and provides GraphQL mutations and queries to be used by the PWA developers.
These mutations and queries are the correspondent update (POST) and read (GET) calls to the Klarna APIs. This means that the extension will work as a translation layer between GraphQL and the REST API of Klarna.
More information can be found in GraphQL tutorial