API Mocking with Mock Service Worker for REST and GraphQL

Modern web development requires seamless integration with APIs, but relying on live backends during development and testing often leads to slow workflows and brittle tests. Mock Service Worker (MSW) solves this by intercepting network requests at the browser and network level, giving you total control over API responses. In this text-based course, you will transition from struggling with inconsistent API environments to confidently mocking complex network behaviors. You will learn how to write clean, maintainable mock definitions that run seamlessly in both browser environments and Node.js testing setups. What you'll learn: - Understand the core concepts of Service Workers and how MSW intercepts network traffic without altering your application code - Mock REST API endpoints using modern declarative handlers and custom response resolvers - Mock GraphQL queries and mutations to handle complex data fetching scenarios - Configure MSW for both browser-based prototyping and Node.js-based unit and integration testing - Handle advanced scenarios like network errors, latency simulation, and dynamic mock states - Apply best practices for structuring mocks in modern frontend architectures and testing frameworks You will start by learning the foundational terminology of API mocking and Service Workers. From there, you will progress through step-by-step written tutorials and structured code exercises, moving from basic REST mocks to advanced GraphQL scenarios and automated test integration. This course is designed for beginner frontend developers, test engineers, and web developers who want to improve their testing and prototyping workflows. No prior experience with MSW is required, though a basic understanding of JavaScript and APIs is helpful. Start mastering network control today and build more resilient web applications.