What is an adapter service?

An adapter service is a layer between different parts of a system that makes them compatible.

In Angular (and in architecture in general), an adapter:

• hides the implementation details of a third-party API or library;
• converts data or interfaces into a format convenient for the application;
• isolates business logic from a specific technology.

Example: you work with two APIs, one returns snake_case, the other camelCase. The adapter service converts the data into a single format so the rest of the code does not depend on the differences.

The point is to separate "how it works" from "what needs to be done", keeping the code clean and flexible for future changes.