Chapter 1: Introduction & Setup

Welcome to the GraphQL Yoga Book — a practical guide for building scalable and modular GraphQL APIs with GraphQL Yoga.

What is GraphQL Yoga?

GraphQL Yoga is a fully-featured GraphQL Server with focus on easy setup, performance and great developer experience. It's built on top of the following libraries:

• GraphQL.js - The reference implementation of GraphQL
• Envelop - A plugin system for GraphQL
• GraphQL Tools - A set of utilities for building GraphQL APIs

Key Features

• 🔥 Performance: Built on top of the fastest HTTP servers
• 🎯 TypeScript Support: First-class TypeScript support
• 🔌 Plugin System: Extensible through Envelop plugins
• 📦 Zero Dependencies: No external dependencies required
• 🛠 Developer Experience: Great error messages and debugging tools

Setting Up Your First GraphQL Server

Let's create a new project and set up a minimal GraphQL server:

1. First, create a new directory and initialize a new Node.js project:

mkdir graphql-server
cd graphql-server
npm init -y

2. Install the required dependencies:

npm install @graphql-yoga/node graphql

3. Create a new file called index.js (or index.ts for TypeScript) with the following content:

import { createYoga } from '@graphql-yoga/node'
import { createServer } from 'node:http'

// Define your schema
const typeDefs = `
  type Query {
    hello: String
  }
`

// Define your resolvers
const resolvers = {
  Query: {
    hello: () => 'Hello from GraphQL!'
  }
}

// Create your GraphQL server
const yoga = createYoga({
  schema: {
    typeDefs,
    resolvers
  }
})

// Start the server
const server = createServer(yoga)
server.listen(4000, () => {
  console.log('Server is running on http://localhost:4000/graphql')
})

4. Add a start script to your package.json:

{
  "scripts": {
    "start": "node index.js"
  }
}

5. Run your server:

npm start

Testing Your Server

Once your server is running, you can test it by:

1. Opening http://localhost:4000/graphql in your browser
2. Using the GraphQL Playground to run queries
3. Try this simple query:

query {
  hello
}

You should see the response:

{
  "data": {
    "hello": "Hello from GraphQL!"
  }
}

Next Steps

In the next chapter, we'll dive deeper into GraphQL core concepts and learn how to design more complex schemas. We'll explore:

• Types and Fields
• Queries and Mutations
• Input Types
• Enums and Scalars
• And much more!

Summary

In this chapter, we've:

• Learned about GraphQL Yoga and its features
• Set up a basic GraphQL server
• Created a simple schema with a hello query
• Tested our server using the GraphQL Playground

This foundation will help us build more complex GraphQL APIs in the upcoming chapters.