Facebook uses/used PHP, that scales too. If you make it stateless and use it only as a glue. Dropbox uses Python too. Eve Online used Stackless Python. Of cour

Facebook uses/used PHP, that scales too. If you make it stateless and use it only as a glue. Dropbox uses Python too. Eve Online used Stackless Python. Of course Reddit/FB/EVE/Dropbox shards everything, there's no global state to manage via Python. The state lives in the data store layer. And for that there are these monstrous/elegant things like Vitess, that YouTube used (uses?): https://vitess.io/docs/overview/architecture/ https://vitess.io/docs/overview/architecture/ which is basically a sharding/routing layer on top of independent MySQL instances.