Backend
What is Middleware?
Software that sits between a request and response, processing or transforming data along the way.
Definition
Middleware is a function or layer that intercepts requests and responses in a web application. In Express.js, middleware functions have access to the request object, response object, and the next middleware. Common uses include authentication, logging, rate limiting, CORS handling, body parsing, and error handling. Middleware can be applied globally, to specific routes, or composed in chains.