1. Overview and setup

Welcome to the start of your GraphQL journey!

What is ? GraphQL is the developer-friendly language for the modern web. It transforms how apps fetch data from an API, enabling you to get exactly what you need with a single query.

With a strongly typed schema at its core, helps you define relationships between data across any number of systems, empowering you to focus on what your data can do instead of where it's stored.

Throughout this course, we're going to learn how fits into our existing architecture and how it works with existing REST APIs and other . We'll learn how to use queries, , , the schema, and in our GraphQL API.

A diagram showing GraphQL as the contact point between multiple clients and the complex architecture of a modern backend

We'll build a using Hot Chocolate. No, not the warm, chocolatey drink! We're talking about a GraphQL server framework for .NET developers.

Get ready to roll up your sleeves, write some code, test your understanding, and build something cool!

In this lesson, we will:

  • Learn about what we're building
  • Set up our project environment


This course uses C# and .NET 8. You should be familiar with C# basic programming concepts to follow along with this course.

We also recommend being familiar with the basics of how to use REST APIs and HTTP requests.

What we're building

Listen up! Ready to tune into what we're building in this course? Drumroll please 🥁

If you couldn't tell from all those music-related cues, we're building a music catalog API called MusicMatcher that helps us find the right soundtrack for the right moment.

Mockup of MusicMatcher

For this first iteration of MusicMatcher, we'll focus on playlists: showcasing featured playlists, listing a playlist's tracks, and adding tracks. In future courses, we'll add more features like pagination, authentication, intermediate schema design concepts, and federation.

Project setup

To follow along with the course, you will need the following:

Code editor or IDE

We'll be using VS Code but you can feel free to use your favorite editor or IDE for .NET development!

Clone the repo locally

The project repo is the result of running dotnet new web -o Odyssey.MusicMatcher to create a new project based on the ASP.NET Core Empty web template. It also contains some extra instructions in the README on how to get up and running.

git clone https://github.com/apollographql-education/odyssey-intro-hotchocolate

Here's what the project looks like:

📦 Odyssey.MusicMatcher
┣ 📂 Data
┃ ┣ 📄 swagger.json
┣ 📂 Properties
┃ ┣ 📄 launchSettings.json
┃ 📄 appsettings.Development.json
┃ 📄 appsettings.json
┃ 📄 Odyssey.MusicMatcher.csproj
┃ 📄 Odyssey.MusicMatcher.sln
┃ 📄 Program.cs
┗ 📄 README.md

To install dependencies, run:

dotnet build

Don't have .NET installed? Find your download link here. We're using .NET 8 for this course.

Then, check that the project can run successfully:

dotnet run

You should see:

Odyssey.MusicMatcher ❯ dotnet run
info: Microsoft.Hosting.Lifetime[14]
Now listening on: http://localhost:5059
info: Microsoft.Hosting.Lifetime[0]
Application started. Press Ctrl+C to shut down.
info: Microsoft.Hosting.Lifetime[0]
Hosting environment: Development
info: Microsoft.Hosting.Lifetime[0]
Content root path: /Users/your-path/Odyssey.MusicMatcher

The project will be running on http://localhost:5059 by default!


Key takeaways

  • enables precise data retrieval with a single , eliminating the need to navigate multiple REST endpoints on the client app side.
  • Hot Chocolate is a framework for .NET developers.

Up next

Let's dive into all things . In the next lesson, we'll get into the details of how GraphQL fits into our existing architecture and what exactly makes up a .


Share your questions and comments about this lesson

This course is currently in

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