Apollo is a platform of libraries, servers, and tooling for building applications with GraphQL. Its documentation describes Apollo as equipping developers “with the technology you need to design, compose, and deliver anything, from apps to APIs to AI agents.” Where the GraphQL specification defines the query language and execution model, Apollo provides the widely used, production-grade implementations that let teams adopt GraphQL on both the client and the server.
The platform’s two best-known components are Apollo Client and Apollo Server. Apollo Client is a library for querying GraphQL from web, mobile, and other interfaces, with support for React on the web and for iOS and Kotlin on mobile. It manages the network layer, normalizes and caches results, and integrates query state directly into the UI, which made it a popular data layer for single-page applications. Apollo Server is a framework for building GraphQL servers in JavaScript, defining a schema and resolvers that connect the graph to underlying data sources such as databases and REST services.
Apollo’s third pillar is Federation, an architecture for composing multiple independent GraphQL services into a single unified graph, often called a supergraph. Each team owns and operates its own subgraph, and the Apollo Router stitches them together into one endpoint that clients query as if it were a single API. This made GraphQL practical at large organizations with many teams and services, addressing the question of how to scale a single graph across a distributed, microservices-style backend.
Around these core libraries, Apollo built additional products including the Apollo Router, Apollo Connectors for bringing REST APIs and other data sources into a graph, and the GraphOS platform for schema management, observability, and governance. The open-source projects are developed in the open under the apollographql organization on GitHub, while GraphOS is offered as a commercial cloud service by Apollo Graph, Inc., the company behind the platform.
Through this combination of widely adopted open-source libraries and a hosted platform, Apollo became the de facto standard toolchain for GraphQL in industry. For many developers, adopting GraphQL in practice meant adopting Apollo Client and Apollo Server, and its work on Federation shaped how organizations think about evolving and integrating GraphQL APIs across team and service boundaries.