Well, it's not really all that different from any other programming gig, just very low-level. If you have enjoyed systems or maybe embedded programming in the past, you're probably at least a decent candidate.

It's a lot of fun overall, but still, not 100% of the time, for instance you have to interact with dozens of different protocols, all of which are braindead in their own special way. People skills are also more important than a "pure tech" kind of role.

I did have some trading experience already, which probably helped but is not required. It probably did help paper over some softer spots I had on the technical side, though :)