GraphQL Concepts Explained: Differences from REST API, Resolver Structure, and Changes in Collaboration

GraphQL is a query language developed by Facebook. As of 2019, it is still in its early stages but is gaining attention through adoption by platforms like GitHub. Unlike REST APIs, which use various endpoints, GraphQL uses a single endpoint and allows clients to request only the necessary data through query combinations. This reduces multiple network round-trips to a single one, improving performance.

The core structure of GraphQL is the 'Resolver'. Each field is linked to a resolver function, and for non-scalar types, resolvers are called in a chained manner. This process allows database queries to be executed only as needed, enabling efficient design. Additionally, the 'Introspection' feature allows the server to provide real-time schema information to the client. This eliminates the need for manual management and sharing of API specifications (interface documents), which were essential in traditional REST APIs, thereby resolving issues related to documentation overhead and interface inconsistencies.

Due to these characteristics, frontend developers gain more control, and the collaboration culture between backend and frontend is expected to shift towards a more agile and productive direction.