[juandazapata]

Click bait. They mention that they can handle 700 req/s with Symphony, then HAProxy helps to scale up to 1600 req/s. The 1B figure is in 1 week.

[geerlingguy]

More specifically, requests are routed through HAProxy to Varnish, and then, if not cached, they'll hit the backend. I'm surprised they couldn't get up to 5-10,000 req/s, honestly. Maybe payload size/bandwidth limited.

500+ req/sec is decent for a Symfony app, so they should've focused on that metric and the app itself.