Who said nginx can only handle 10k connections? I’m pretty sure that is configurable…

Everyone is talking past each other here. Whether or not NGINX can respond to more regular HTTP requests per second than cowboy I don’t think is a useful metric. NGINX is very fast, nobody is disputing that.

However, the ability to get a new connection, reply quickly, and then drop it (regular HTTP) does not imply that it will hold several hundred thousand connections open indefinitely with reasonable RAM usage. Maybe it will! My point is simply that the wrk benchmark offers no evidence of that behaviour, because it doesn’t test that behaviour.

@NobbZ NGINX can definitely reverse proxy web socket connections, but I too don’t know about what the resource consumption of doing so is.

All in all it’s a good question, although notably you could just cut NGINX out of the picture entirely by not using a reverse proxy. For our production servers for example we just run cowboy on 8080, and then the AWS load balancer routes port 80 traffic to 8080.

wrk is known to have problems with cowboy and applications based on that.

Running the tool to measure on the same host as the thing you measure is a bad idea as well.