Broberto gave you the correct answer
You can split backend services in two categories, some are made to be requested from anywhere including a browser, some are made to be used by others backend and so requested from a server, not a browser.
WeWeb is a front end app builder, it will be executed from the user browser, so you must connect to backend services from the first category, the one made to be requested from a browser.
Normally, to be able to connect securely to the second category from a browser, you should connect to a backend from the first category and this backend will do the server-to-server request.
To make it easier for people to built their project on top of popular services like openai and airtable, we made special microservices so they can be used directly in WeWeb.
Theses microservices act as a micro backend in between, it define a restricted list of usable endpoints, and inject the private API Key on the fly so it would never be exposed publicly in the frontend.
The microservice is very simple and naive, it allow people to add easily public data from their Airtable or adding some OpenAI features, but if you want to control precisely who should be able to consume your openai or your airtable data, you have to use a proper backend in between that will handle the access rules.
