What is Koa.js?

Koa is a new web framework designed by the team behind Express, which aims to be a smaller, more expressive, and more robust foundation for web applications and APIs. Through leveraging generators Koa allows you to ditch callbacks and greatly increase error-handling. Koa does not bundle any middleware within core, and provides an elegant suite of methods that make writing servers fast and enjoyable.

Does Koa replace Express?

Koa is more like Connect, but a lot of the Express goodies were moved to the middleware level in Koa to help form a stronger foundation. Koa makes middleware more enjoyable and less error-prone to write, for the entire stack, not just the end application code.

Typically many middleware would re-implement similar features, or even worse incorrectly implement them, when features like signed cookie secrets among others are typically application-specific, not middleware specific.

Why is not Koa Express4.0?

Koa is a pretty large departure from what people know about Express, the design is fundamentally much different, so the migration from Express 3.0 to this Express 4.0 would effectively mean rewriting the entire application, so we thought it would be more appropriate to create a new library.

Why you should learn Koa?

• Promise based flow in Koa
• No Callbacke hell in Koa
• Better error handling through try/catch in Koa
• Koa is more modular
• Better user experience in Koa
• Proper stream handling in Koa

What you will learn in this course

• Fundamentals of Koa
• Building API from scratch in Koa
• Integrating Koa with Sequelize
• How to use Mysql with Koa
• Adding relationship between models in Sequelize
• Adding authentication in Koa and Sequelize
• Adding documentation for REST APIS in Koa