Glossary: Software Design Patterns in JavaScript

Express (and Fastify, Koa, Next.js)

Also written: Express, Express.js, Fastify, Koa, Next.js

Express is the most used web framework for Node: you register routes and middleware with app.get and app.use, and it calls them when requests arrive. Fastify, Koa and Next.js use the same ideas of inversion of control, injection and middleware.