gqlgen

gqlgen is a Go library for building GraphQL servers. GraphQL is a way to define an API where clients specify exactly what data they need, and the server returns only that. This library is made for developers writing Go applications who want to expose a GraphQL API without writing a lot of repetitive boilerplate code.

The library is schema-first, which means you start by writing a file that describes your API using GraphQL's own schema language. From that schema, gqlgen automatically generates the Go code that handles incoming queries, validates data types, and wires everything together. You then fill in the actual logic, such as fetching data from a database, without worrying about the scaffolding.

Type safety is a central priority. The generated code uses concrete Go types rather than generic key-value maps, which means the Go compiler can catch mistakes at build time rather than at runtime. This is a deliberate choice to reduce a category of bugs that shows up in more loosely typed approaches.

Getting started requires a few steps: initializing a Go module, adding gqlgen as a dependency, running the initialization command to generate a configuration file and initial models, and then running a server. The documentation site at gqlgen.com includes a step-by-step tutorial and real-world example projects.

The library also handles more advanced patterns, such as lazy-loading related objects only when a client actually requests them, customizing how GraphQL IDs map to Go integer or string types, and tuning how many field resolvers run concurrently. Configuration lives in a YAML file that lets you adjust type mappings and generation behavior without modifying generated code by hand.