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Type-safe GraphQL for Go
You are looking at the docs for an older version (v0.17.27). The latest version is v0.17.46.

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What is gqlgen?

gqlgen is a Go library for building GraphQL servers without any fuss.

Still not convinced enough to use gqlgen? Compare gqlgen with other Go graphql implementations

Quick start

  1. Initialise a new go module

    mkdir example
    cd example
    go mod init example
  2. Add github.com/99designs/gqlgen to your project’s tools.go

    printf '//go:build tools\npackage tools\nimport (_ "github.com/99designs/gqlgen"\n _ "github.com/99designs/gqlgen/graphql/introspection")' | gofmt > tools.go
    go mod tidy
  3. Initialise gqlgen config and generate models

    go run github.com/99designs/gqlgen init
    go mod tidy
  4. Start the graphql server

    go run server.go

More help to get started:

Reporting Issues

If you think you’ve found a bug, or something isn’t behaving the way you think it should, please raise an issue on GitHub.


We welcome contributions, Read our Contribution Guidelines to learn more about contributing to gqlgen

Frequently asked questions

How do I prevent fetching child objects that might not be used?

When you have nested or recursive schema like this:

type User {
  id: ID!
  name: String!
  friends: [User!]!

You need to tell gqlgen that it should only fetch friends if the user requested it. There are two ways to do this;

Write a custom model that omits the friends field:

type User struct {
  ID int
  Name string

And reference the model in gqlgen.yml:

# gqlgen.yml
    model: github.com/you/pkg/model.User # go import path to the User struct above

If you want to keep using the generated model, mark the field as requiring a resolver explicitly in gqlgen.yml like this:

# gqlgen.yml
        resolver: true # force a resolver to be generated

After doing either of the above and running generate we will need to provide a resolver for friends:

func (r *userResolver) Friends(ctx context.Context, obj *User) ([]*User, error) {
  // select * from user where friendid = obj.ID
  return friends,  nil

You can also use inline config with directives to achieve the same result

directive @goModel(model: String, models: [String!]) on OBJECT
    | SCALAR
    | ENUM
    | UNION

directive @goField(forceResolver: Boolean, name: String, omittable: Boolean) on INPUT_FIELD_DEFINITION

type User @goModel(model: "github.com/you/pkg/model.User") {
    id: ID!         @goField(name: "todoId")
    friends: [User!]!   @goField(forceResolver: true)

Can I change the type of the ID from type String to Type Int?

Yes! You can by remapping it in config as seen below:

  ID: # The GraphQL type ID is backed by
      - github.com/99designs/gqlgen/graphql.IntID # a go integer
      - github.com/99designs/gqlgen/graphql.ID # or a go string
      - github.com/99designs/gqlgen/graphql.UintID # or a go uint

This means gqlgen will be able to automatically bind to strings or ints for models you have written yourself, but the first model in this list is used as the default type and it will always be used when:

There isn’t any way around this, gqlgen has no way to know what you want in a given context.

Why do my interfaces have getters? Can I disable these?

These were added in v0.17.14 to allow accessing common interface fields without casting to a concrete type. However, certain fields, like Relay-style Connections, cannot be implemented with simple getters.

If you’d prefer to not have getters generated in your interfaces, you can add the following in your gqlgen.yml:

# gqlgen.yml
omit_getters: true

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