Object types in GraphQL

Introduction

Object types let you define the shape of data you want to get or send. They organize information clearly.

When you want to describe a user with fields like name and email.

When you need to fetch a list of books with title and author details.

When you want to send structured data in a query or mutation.

When you want to make your API easy to understand and use.

When you want to reuse the same data structure in many places.

Syntax

GraphQL

type TypeName {
  fieldName1: FieldType1
  fieldName2: FieldType2
  ...
}

Each field has a name and a type.

Types can be scalars like String, Int, or other object types.

Examples

This defines a User with an id, name, and age.

GraphQL

type User {
  id: ID
  name: String
  age: Int
}

A Book has a title and an author which is a User object.

GraphQL

type Book {
  title: String
  author: User
}

Query type to get lists of users and books.

GraphQL

type Query {
  users: [User]
  books: [Book]
}

Sample Program

This schema defines a User object type and a Query to get one user.

GraphQL

type User {
  id: ID
  name: String
  email: String
}

type Query {
  getUser: User
}

Important Notes

Object types are the main way to describe data in GraphQL.

Fields can be other object types, allowing nested data.

Use capitalized names for types by convention.

Summary

Object types define the shape of data in GraphQL.

They have named fields with specific types.

They help organize and reuse data structures.