GraphQL is a query language for APIs and a runtime for fulfilling those queries with your existing data. GraphQL provides a complete and understandable description of the data in your API, gives clients the power to ask for exactly what they need and nothing more, makes it easier to evolve APIs over time, and enables powerful developer tools.

When should I use GraphQL?

GraphQL is intended to be the outward facing HTTP API for any kind of application but it is most powerful when the data is normalized with highly interconnected Collections|Tables|Nodes. The GraphQL Query Language (GQL) is designed to project interconnected data in a very intuitive and flexible way.

Implementations

GraphQL itself is a Spec and is implemented by a number of different programming languages. These are the most popular supported languages

• GraphQL.js
• graphql-ruby
• Graphene (Python)
• Sangria (Scala)
• graphql-java
• graphql-clj (Clojure)
• graphql-go
• graphql-php
• graphql-dotnet (C# / .Net)
• absinthe (Elixir)

Client Libraries

Running queries from the client side can be done with any HTTP client but client side libraries can be very beneficial.

• Relay
• Apollo
• Lokka

Dev Tools

• graphiql /ˈɡrafək(ə)l/ - An interactive in-browser GraphQL IDE.
• libgraphqlparser - A GraphQL query language parser in C++ with C and C++ APIs.
• GraphQL Language Service - An interface for building GraphQL language services for IDEs (diagnostics, autocomplete etc).