File uploads are a core feature in most modern web applications — whether it’s profile pictures, product images, documents, or CSV imports. Express.js doesn’t handle multipart/form-data out of the box, which is why we need Multer .

This is your one-stop, brain-friendly guide to mastering file uploads with Multer.

Why Do We Need Middleware for File Uploads?

HTML forms with enctype="multipart/form-data" send data differently from regular application/x-www-form-urlencoded forms.

Text fields → easy

Files → binary data + metadata

Node.js/Express req.body and req.query can’t parse this format natively.…