Multer

Multer is a Node.js middleware specifically designed for handling `multipart/form-data`, primarily used for processing file uploads in web applications built with the Express.js framework. It efficiently parses incoming request bodies and populates `req.body` with text fields and `req.file` or `req.files` with uploaded files, depending on the configured upload strategy. Built on top of `busboy`, Multer focuses exclusively on `multipart/form-data` and will not process other form encodings. The current stable version is 2.1.1, released on March 4, 2026, with a consistent release cadence that includes frequent security patches. It is a widely adopted library within the Express ecosystem for file upload functionalities.