APIs from Scratch: Designing, Building, and Consuming Web APIs

Build the Backbone of Modern Software — One Endpoint at a Time.

APIs from Scratch is your complete guide to understanding, designing, building, and using web APIs — the essential communication layer powering modern applications, mobile apps, and cloud services.

Whether you’re new to backend development or seeking to strengthen your architecture and integration skills, this book walks you through the fundamentals of REST, HTTP methods, JSON, authentication, versioning, and more. You’ll build your own API step-by-step using Node.js, Express, Python (Flask or FastAPI), or other frameworks, and learn how to consume APIs using tools like Postman, Fetch API, or Axios.

✅ What APIs are and how they power the internet
✅ RESTful design principles and HTTP request/response cycles
✅ Building your own APIs from scratch using Express, Flask, or FastAPI
✅ Handling CRUD operations with real-world data
✅ API testing with Postman and automated testing tools
✅ Authentication and authorization with API keys, JWT, and OAuth2
✅ Rate limiting, error handling, and versioning
✅ Writing clean, scalable, and well-documented endpoints
✅ Consuming public APIs using JavaScript (Axios/Fetch)
✅ Best practices for deploying APIs to platforms like Heroku, Vercel, and AWS