You should never expose your application server directly to the Web. There might be unknown entry points, backdoors, possible data leaks, exploits etc.

Preferably put a filtering proxy in front and whitelist only the URIs you know are valid.
Bonus : LB + rewrite rules + caching.

Nginx is a proven solution, Hiawatha, Apache too etc.

I think its because the permissions binding to port 80. Under most linux distributions packages for NGinX, Apache or other software are already prepared in a way to be ablt to bind that port and reverse proxy is configured in 3 or 4 lines in most of them.

Setting everything up, that your cowboy application is allowed to bind to 80 might be much harder to configure (thats an assumption, I actually never tried to).

But perhaps someone who tried can tell?

@benwilson512 has some phoenix applications in the wild AFAIK (but behind HA AFAIK)

I’ve been happily exposing cowboy but by forwarding port 80 to 4000. I don’t see why it would be an issue other than you I wouldn’t want to run it as root.