File Uploads in Express: Multer, Cloudinary, and the Buffer Problem Nobody Warns You About

Continuing my Express roadmap (auth, CRUD, and databases are behind me — this is Phase 4), I finally sat down to actually understand file uploads instead of copy-pasting Multer boilerplate. Here's what I learned building a small /upload route from scratch. express.json() parses request bodies as text. A file is binary data — sending it as JSON would mean base64-encoding it, bloating the size by 33%. Instead, file uploads use multipart/form-data, a format that packages multiple "parts" (text fiel