From the screenshot I wanted to say, couldn't this be done on a single VPS? Seemed over engineered to me. Then I realized the silly pixels are on top of a map of the entire earth. Dang!

I'm curious what the peak req/s is like. I think it might be just barely within the range supported by benchmark-friendly web servers.

Unless there's some kind of order of magnitude slowdowns due to the nature of the application.

Edit: Looks like about 64 pixels per km (4096 per km^2). At full color uncompressed that's about 8TB to cover the entire earth (thinking long-term!). 10TB box is €20/month from Hetzner. You'd definitely want some caching though ;)

Edit 2: wplace uses 1000x1000 px pngs for the drawing layer. The drawings load instantly, while the map itself is currently very laggy, and some chunks permanently missing.