Express.js is a minimal web framework for Node.js. It adds routing, middleware and response helpers on top of Node's built-in http module.
With plain http, one callback parses the URL, reads the body stream and sets headers such as Content-Type itself. Express gives you routes such as app.get('/users/:id', handler), a middleware chain for shared steps such as authentication, and helpers such as res.json().
Teams use it for REST APIs and server-rendered sites. Its small core is quick to learn, and middleware packages add most other features. It is unopinionated, so it does not pick a folder structure, a validation library or a database for you. Express 5 is the current major version and needs Node.js 18 or later.
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