Well, nignx inc does first develop their proprietary software... Then, they "open" some features. With nginx plus, you're locked to nginx, like when you were us

Well, nignx inc does first develop their proprietary software... Then, they "open" some features. With nginx plus, you're locked to nginx, like when you were using a F5 load-balancer! HAProxy Technologies pushes first its developments in the -dev community branch. Check the commits for the feature given above (SRV records, non exhaustive list of patches): http://git.haproxy.org/?p=haproxy.git&a=search&h=HEAD&st=commit&s=SRV+record http://git.haproxy.org/?p=haproxy.git&a=search&h=HEAD&st=com... HAProxy technologies simply makes the effort of maintaining a branch of HAProxy in which some -dev features are backported. That way, users of HAProxy Enterprise have the most stable and feature reach version of HAProxy. And as Willy stated, every user of HAProxy Enterprise also have access to the source packages. So from a business point of view, the main difference between HAProxy and nginx is that HAProxy is the respects both its community and customers.