HAProxy is a TCP&#x2F;HTTP load balancer, so the entire perspective of the software (from configuration to feature emphasis) stems from that.<p>Squid is a caching HTTP proxy, which began with forward proxying but also supports reverse proxying. I wouldn&#x27;t regard it as relevant to modern, dynamic architectures as HAProxy or Varnish (another caching-focused project).<p>There&#x27;s no real difference in open source purity between any of these projects, unless you dislike the stewardship of a company. HAProxy has existed for a long time without such stewardship (as has Varnish). Indeed, Squid&#x27;s lack of commercial backing might be a hint as to its current relevance.