GraphQL + Apollo Stack

GraphQL is a query language and runtime specification for APIs originally developed at Facebook and open-sourced in 2015. Apollo is a separate commercial entity and open-source project that provides client, server, and developer tooling libraries built on top of the GraphQL specification, adding features like normalized caching, state management, and developer tooling.

Apollo Client normalizes GraphQL responses into a local in-memory cache by breaking objects down and storing them under keys derived from their id and __typename fields. This normalized approach allows multiple queries that reference the same entity to share cached data, and the client can automatically update the UI when a mutation modifies a cached object.

On the client side, alternatives include Relay (developed by Meta), urql, and lighter-weight options like graphql-request. On the server side, developers can use the reference graphql-js implementation directly or frameworks like GraphQL Yoga, Mercurius for Node.js, or Graphene for Python, depending on their language and runtime preferences.

Yes, a GraphQL server using Apollo Server can act as a gateway layer that resolves GraphQL fields by making HTTP requests to existing REST endpoints behind the scenes. This pattern allows teams to incrementally adopt GraphQL without rewriting their entire backend, with the Apollo server fetching from REST APIs, databases, or third-party services as needed.