Data Hub plugin for Pimcore is based on GraphQL, which is a query language for APIs. After sending a GraphQL query to your API endpoint, you will get exactly what you need, since GraphQL returns completely predictable results.
API endpoints are configured in Pimcore admin with schema defintions to provide structure for accessing and creating the data.
products: product related data like Cars, AccessoryParts, Categories etc.
shop: shop related information like Orders, OrderItems, Vouchers.
assets: media related to Brands, Products etc. Data Hub plugin supports Queries and Mutation for Data Objects & Assets.
Try live examples!
Product - Car (add more fields in query: numberOfDoors, numberOfSeats, productionYear)
Product - Accessory Part (add more fields in query: erpNumber, condition, owner)
Assets - Brand Logo Image (add more fields in query: mimetype, filesize)
Mutation - Create Car Object (run query to create car object under folder "/upload/new")
For a live example of content-as-a-service (CaaS) / headless CMS please have a look at the events page. This page fetches the data from Pimcore backend via GraphQL with a Data Hub endpoint.