[nightpool]

"You want a high-availability website allows user-uploaded files and does asynchronous task processing? You're probably going to have to get familiar with servers, load balancers, queues, and object storage, at a minimum."

Really? I disagree. I could probably build that with Rails and Heroku in an afternoon, after creating a single S3 bucket and an access key for presigned POST. AWS has "necessary complexity" in the same way a giant hole in your head improves your brain's cooling potential. (i.e. maybe, in some very rare cases, but you almost certainly don't need it)

[esperent]

Now scale it to twenty million concurrent users.

[nightpool]

Are you kidding me? Amazon, on their biggest day of the entire year (Prime Day), reached peak traffic of approximately 290m requests per minute through CloudFront. I would bet that loading a single Amazon page uses much less than a minute and serves more than 10 requests per page load.

If you're not going to be as big as the entirety of Amazon you don't need to serve 20 million concurrent users. Ever.

[esperent]

Ok, pick whatever smaller number makes you happy then. My point is just as valid with 100k concurrent users.