API Development in Swift (iOS/macOS)

This book is a practical guide to creating and integrating APIs in the Apple ecosystem. You will learn to design, develop, and test server-side and client-side APIs using modern Swift features.

Who this book is for:

• iOS/macOS developers who want to master the server side of Swift
• Beginner programmers familiar with Swift basics who want to understand how APIs work
• Professionals transitioning from other languages (Python, Java) to Swift for backend development
• Developers seeking to improve the network layer architecture in their applications

What you will learn:

• Basics of HTTP, REST, and WebSocket protocols
• Working with URLSession — from simple requests to complex file downloads
• Building server applications with Vapor 4 (routing, middleware, databases)
• Error handling and response caching
• Using Combine for reactive network stream processing
• Security: OAuth2, JWT, data encryption
• Testing APIs with XCTest and Postman
• Performance optimization and working with multithreading
• Deploying server applications on macOS Server and Linux

Each chapter contains real code examples ready for use in your projects. You will learn to build scalable APIs that are easy to maintain and extend. The book covers both the client side (iOS applications) and the server side (macOS/Linux).

After reading, you will be able to independently create full-fledged backend solutions in Swift, integrate them with iOS/macOS applications, and confidently work with any network protocols. Examples include building a WebSocket chat server, a REST API for an online store, and a microservice architecture.

The book is written in simple language with an emphasis on practice. It is suitable both for self-study and for courses on Swift development.