Chrome allows 32 connections through an HTTP/1.1 proxy, and the queue is invisible from the proxy side

Easy one to miss if you run a lot of pages in one automated Chrome behind a proxy: Chrome allows 32 simultaneous connections through an HTTP/1.1 proxy. Past that, requests wait inside the browser before the proxy ever sees them. So throughput sits flat no matter how many tabs you add, and it’s tempting to blame the proxy and go looking for a bigger plan. That won’t help. Splitting the work over several browsers will. Two more Chrome oddities in the same area. A user:pass@ URL in --proxy-server fails with net::ERR_NO_SUPPORTED_PROXIES, because Chrome doesn’t use credentials embedded in proxy settings. And a password-protected SOCKS5 server doesn’t work at all, since Chrome supports no SOCKS5 auth methods, so you get net::ERR_SOCKS_CONNECTION_FAILED whatever your code does.