An API is a Server. This may seem obvious, but really needs to be understood. A server is an app that has no visual representation and is always running. Usually connected to a network and shared among many clients (UIs, web apps, mobile apps, other servers, etc). Servers usually sit in front of a DB and facilitate access to that DB.
It's an intermediator between the server and database. It interact with database in an object-oriented approach.
Prsima is a DB agnostic, type safe ORM.
- is to teach the database about the shape of the data or if you already have a schema and wants to have change to it, you can do migrations.
WTs or JSON Web Tokens are most commonly used to identify an authenticated user. They are issued by an authentication server and are consumed by the client-server (to secure its APIs).