How to Build a GraphQL API in Go

Build a GraphQL API in Go by defining your schema, generating code, and wiring handlers to your data source.

package main

import (
	"github.com/99designs/gqlgen/graphql/handler"
	"github.com/99designs/gqlgen/graphql/playground"
	"net/http"
)

func main() {
	h := handler.New(&executableSchema{})
	h.AddTransport(playground.Handler("GraphQL Playground", "/graphql"))
	h.AddTransport(http.NewTransport())
	http.Handle("/graphql", h)
	http.ListenAndServe(":8080", nil)
}

1. Define your schema in schema.graphql to specify types and queries.
2. Run go run github.com/99designs/gqlgen generate to create resolvers and executable schema.
3. Implement resolver logic in resolver.go to fetch data for your queries.
4. Start the server with http.ListenAndServe to expose the /graphql endpoint.

You create a GraphQL API in Go by writing a file that describes your data structure and then running a tool that generates the code needed to handle requests. This approach lets you define exactly what data clients can ask for, and Go automatically builds the server to serve it. It is like drawing a blueprint for a house and then using a machine to build the walls and roof based on that drawing.