Randstad USA, a provider of HR services and staffing, has singled out full-stack developer, big data engineer, security engineer, IoT architect, and VR/AR engineer as .

In many of those cases, Randstad has tracked exploding demand — anywhere from 45 to 117 percent more job listings year-over-year — and listed skills and specializations that might not seem obvious at first glance. But some of these jobs are staple positions that would be tops in most any year, and Randstad’s list is as notable for what’s missing as what is present.

“Big data engineer” seems like an obvious on-fire specialty for the year, and other companies have reached the same conclusion. Staffing and recruiting firm Robert Half saw for such positions range from $135,000 to $196,000. Randstad’s estimates are more conservative — $121,950 to $159,800 — but the number of such jobs tracked by Randstad nearly doubled over the course of 2016.

Randstad also considers big data to be highly synonymous with sensitive data, as the certifications listed for that job type include secret and top secret clearances. Given that big data security is , it might be a good idea to start addressing that problem from the human side rather than the technology side.

, , and — most important — . This last is typical for any nascent or emerging field, so Randstad has tracked more than a doubling of job offers for IoT architect over the past year. (Indeed.com has seen .)

IoT’s skill set is somewhat reminiscent of the full-stack developer set, as both back-end (AWS) and front-end (UX) skills figure into the list. Randstad also expects IoT to be in-the-field, hands-on work in potentially far-flung settings, as one of the recommended certifications is Water Safety Instructor.

seems like a contender — but there’s no question smart, skilled people will be needed to build those positions. Randstad only counted 45 percent more IoT job listings over the last year, and the pay is still conservative compared to that of the other fields mentioned here, but an increase is still an increase.

What’s not in Randstad’s top five? Blockchain and machine learning, to name two oft-cited movers and shakers in modern IT. Blockchain tech is gradually disassociating itself from its long-standing default case (bitcoin), especially as come to the fore and invest in the underlying tech. But there hasn’t yet been the kind of market-wide breakthrough in demand for it one has seen with other technologies.

Other job surveys of IT, , have shown machine learning/AI-related tech leading the pack when it comes to emerging technologies. It’s possible some of the work done in this field can be folded into the heading of “big data,” especially since ML/AI rely on data sets and not only algorithms to do their magic. But this is one field that deserves to be singled out as it grows in both size and influence.