Learn
How browser file uploads actually work — the protocols, the failure modes and the security rules — written to be useful whatever backend you run. Nothing here is specific to one framework.
Splitting a file with Blob.slice(), the wire format, reassembly on the server, and what a resumable protocol adds on top.
What the browser can usefully check — extension, size, magic bytes, image dimensions — and why none of it is a security control.
The server-side rules a JS uploader cannot enforce for you, and the browser-side ones it can: file-name XSS, spoofed types, and safe redisplay.
The questions that actually decide it: bundle size, dependencies, transport support, framework coupling, and who owns the server half.
Looking for code rather than concepts? The demos are runnable, the backend guides cover Node, PHP, Python, Go and .NET, and the API reference lists every option.