TypeSpec is a language and toolset developed by Microsoft for defining data models and service APIs. It provides a structured way to describe the shape and behavior of data and services, ensuring consistency and reducing errors in API development. With TypeSpec, you can generate code, documentation, and other artifacts from your API definitions, making it easier to maintain and evolve your services. Microsoft uses TypeSpec internally to define APIs for various products and services, including Azure

TypeSpec is used to define the interface of your API, which clients will use to interact with resources provided by your service. This includes specifying the operations, request and response models, and error handling mechanisms. The actual API logic is implemented in the backend service, which processes the requests and communicates with the database.