GraphQL on C# (.NET): Building Modern APIs

The book "GraphQL on C# (.NET)" is a comprehensive guide for developers seeking to master the modern approach to building APIs using GraphQL in the .NET ecosystem. In a world where flexibility and performance of client-server interaction are paramount, GraphQL becomes an indispensable tool, allowing clients to request only the data they truly need.

The author, Alexey Petrov, is an experienced .NET developer and architect, sharing practical knowledge gained from implementing GraphQL in dozens of commercial projects. The book is structured on the "from simple to complex" principle and contains many ready-to-use code examples.

What you will learn from the book:

• GraphQL Basics: data types, schemas, queries, mutations, and subscriptions.
• Integration with .NET: connecting the Hot Chocolate library, configuring middleware, and server setup.
• Schema Design: creating flexible and scalable schemas, working with interfaces, unions, and custom directives.
• Working with Data: connecting Entity Framework Core, optimizing queries with DataLoader, solving the N+1 problem.
• Authentication and Authorization: securing GraphQL endpoints, using policies and custom attributes.
• Testing and Debugging: writing integration tests, working with GraphQL Playground and Banana Cake Pop.
• Advanced Techniques: implementing real-time subscriptions via WebSocket, fragments, variables, and pagination.

Who this book is for:

The book will be useful both for beginner .NET developers who want to learn GraphQL from scratch, and for experienced professionals looking to deepen their knowledge and master best practices. Basic familiarity with C#, ASP.NET Core, and REST API principles is assumed.

The reader will learn not only to write code but also to make architectural decisions: when to use GraphQL instead of REST, how to properly design a schema for complex domain models, and how to ensure high API performance under load.

Special attention is paid to the .NET ecosystem: you will learn how to integrate GraphQL with popular libraries (AutoMapper, FluentValidation, Serilog) and how to deploy the finished solution in Docker and cloud environments (Azure, AWS).

By the end of the book, you will be able to independently build a full-fledged GraphQL server in C# that is ready for production use. All code examples are available in the repository and come with detailed comments.

This book is your practical guide to the world of modern APIs on the .NET platform. Start creating more efficient and client-friendly services today!