It's legit. That's the going rate for this position. The company is keeping a low profile, but you'll learn more about us once you apply.

I can't personally move to Puerto Rico for this job, or I would. But I'm consulting for them. A fastmail alias was just the easiest way for me to get a temporary address.

FWIW, while the money may seem big it’s not out of line for the industry, especially given that the role looks to require a decent level of experience.