Schema documentation in GraphQL

Introduction

Schema documentation helps explain what each part of your GraphQL schema means. It makes it easier for others to understand and use your API.

When you want to help your team understand the data your API provides.

When you build an API that others will use and need clear instructions.

When you want to keep track of what each field and type in your schema does.

When you want to generate automatic API docs from your schema.

When you want to reduce confusion and mistakes by explaining your schema clearly.

Syntax

GraphQL

"""This is a description"""
type TypeName {
  """Field description"""
  fieldName: FieldType
}

Use triple double quotes """ to add descriptions above types and fields.

Descriptions appear in tools like GraphQL Playground or GraphiQL to help users.

Examples

This example shows how to document a type and its fields.

GraphQL

"""A user in the system"""
type User {
  """Unique ID of the user"""
  id: ID!
  """User's full name"""
  name: String
}

Here, the query and its field are documented to explain their purpose.

GraphQL

"""Query root"""
type Query {
  """Get a user by ID"""
  user(id: ID!): User
}

Sample Program

This schema documents the Query type and the Book type with descriptions for each field.

GraphQL

"""Root query type"""
type Query {
  """Fetch a book by its ID"""
  book(id: ID!): Book
}

"""A book object"""
type Book {
  """Unique identifier for the book"""
  id: ID!
  """Title of the book"""
  title: String!
  """Author of the book"""
  author: String
}

Important Notes

Descriptions should be clear and concise to help users quickly understand the schema.

Use documentation to improve collaboration and reduce errors when using the API.

Summary

Schema documentation uses triple quotes to add descriptions.

It helps users understand the API without guessing.

Good documentation improves teamwork and API usability.