GraphQL on C# (.NET): Complete Guide

The book "GraphQL on C# (.NET)" is a practical guide for developers seeking to master a modern approach to building APIs using the C# language and the .NET platform. Unlike REST, GraphQL provides clients with the flexibility to request only the necessary data, which is especially important for complex systems, mobile applications, and microservice architecture.

The author consistently guides the reader from basic concepts to professional techniques for working with GraphQL in the .NET ecosystem. The book is aimed at C# developers familiar with the basics of ASP.NET Core and Entity Framework Core, but does not require prior knowledge of GraphQL. Each chapter contains practical examples, ready-to-use code snippets, and design recommendations.

What you will learn:

• Principles of GraphQL: types, schemas, queries, mutations, and subscriptions.
• Setting up a GraphQL server on .NET 8 using the Hot Chocolate library.
• Designing flexible and type-safe schemas for real-world projects.
• Integration with Entity Framework Core for efficient data loading (DataLoader, N+1 problem).
• Error handling, validation, and authorization in GraphQL API.
• Subscriptions for working with real-time data via WebSocket.
• Performance optimization: caching, batching, pagination.
• Testing and documenting GraphQL API (GraphQL Playground, Banana Cake Pop).

Who this book is for:

• Backend developers in C# looking to replace REST with a more modern protocol.
• Full-stack engineers building APIs for clients with different data needs.
• Architects evaluating GraphQL for microservice architecture on .NET.
• Students and beginner programmers learning modern approaches to API development.

Edition features:

• Relevance: all examples are based on .NET 8 and Hot Chocolate 13+.
• Practical focus: over 50 ready-to-use code examples.
• Advanced topics: federation (schema federation), Apollo Studio, GraphQL over HTTP/2.
• Real-world cases: online store, booking system, dashboard.

This book will be your guide to the world of GraphQL on the .NET platform. You will not only learn the theory but also gain practical skills that you can immediately apply in your projects. Whether you are building a new API or migrating an existing REST service, "GraphQL on C# (.NET)" will give you all the necessary tools and knowledge.