Features
- Async/await-native middleware with cascading
- Lightweight core with no bundled middleware
- Context object encapsulates request and response
- Better error handling with try/catch
Pros
- Cleaner async/await middleware pattern than Express
- Smaller, more focused core
- Created by Express original team with lessons learned
Cons
- Much smaller ecosystem than Express
- Requires assembling middleware for basic features
- Less community activity and fewer learning resources
Overview
Koa is a web framework created by the team behind Express, designed to be a smaller, more expressive, and more robust foundation for web applications and APIs. It leverages async/await to eliminate callbacks and greatly improve error handling.
Koa’s middleware uses a “cascading” pattern where each middleware can perform actions both before and after the next middleware, making the flow of control intuitive. Unlike Express, Koa bundles no middleware by default, giving developers full control over their stack.
When to Use
Choose Koa when you want a minimal framework with clean async/await patterns and prefer to compose your own middleware stack. It’s best for developers who find Express too opinionated and Fastify too structured.
Getting Started
npm init -y && npm install koaimport Koa from "koa";
const app = new Koa();
app.use(async (ctx) => {
ctx.body = { message: "Hello from Koa" };
});
app.listen(3000);