My heart says OpenBSD; but I belive it is better to use Linux in a company (not yours) usually because you can get more people to use/embrace Linux because it is commodity.

If you are building your own product/service; then OpenBSD security could give you some kind of unlawful advantage that Linux won't.

Linux if you don't understand why you would want BSD. BSD if you do.

I don't know why this got downvoted - it hits the nail on the head IMO.

OP if you even have to ask the question ... go with Linux, seriously.

It is more popular, has more support and I'm 100% certain you likely aren't doing anything niche or special enough for any of the BSDs to give you a competitive edge.

People don't like answers thank make them think, they need easy answer, use B but not A and that's it.

Totally agree with you, the author of the comment is absolutely right. The question couldn't get better answer.

Not enough context. The people that will maintain it, what you will be serving, in which infrastructure, workflow around it, time, the rest of the system and more could change which one would be the "best". With all those factors unknown, I would probably take Linux.

Either is fine. But from a security standpoint: OpenBSD.

I would use linux because my dev machine is linux. I want production env match my dev env, for easy debugging and issue reproducing.

I only had Linux severs for web servers (Cent OS and Ubuntu Server) ... I didn't have a problem and I stuck with the winning team.

You don't define your use case, so it's really impossible to answer.