We've used HAProxy for load balancing and High availability systems with failover for postgres and redis.
Then we've used Nginx behind that as the Reverse Proxy, static media serving, and basic static caching.
Basically HAproxy seems better for well... High availability and as a load balancing proxy. And Nginx has seems to be more suited for the HTTP(s) type pipeline.
You if all you need is basic load balancing, or some types of HA, then nginx will work fine. Last I checked (few years ago) nginx has a lot more http routing tools and http focused settings, headers, static file serving, etc. But HAProxy might have improved in the last 3 years with those.
Then we've used Nginx behind that as the Reverse Proxy, static media serving, and basic static caching.
Basically HAproxy seems better for well... High availability and as a load balancing proxy. And Nginx has seems to be more suited for the HTTP(s) type pipeline.
You if all you need is basic load balancing, or some types of HA, then nginx will work fine. Last I checked (few years ago) nginx has a lot more http routing tools and http focused settings, headers, static file serving, etc. But HAProxy might have improved in the last 3 years with those.