GraphQL is an open-source query language and runtime for APIs (Application Programming Interfaces). GraphQL provides a flexible and efficient approach to fetching and manipulating data between client applications and servers. It allows developers to define a schema that describes the available data and operations in a strongly-typed manner. This enables automatic documentation generation, tooling support, and helps prevent common errors during development.
Unlike traditional REST APIs, where clients have limited control over the structure and amount of data they receive, GraphQL allows clients to specify exactly what data they need and retrieve it in a single request. This avoids over-fetching or under-fetching of data, leading to more efficient and performant applications.
In GraphQL, clients define a query that describes the data requirements, including the fields and relationships they want to retrieve. The server then responds with a JSON object that matches the structure of the query. This allows clients to gather all the necessary data in a single request, reducing the number of round trips to the server.
GraphQL also supports mutations, which enable clients to modify data on the server. Clients can specify the exact changes they want to make and receive the updated data in response.