Embedded Systems
Also written as Embedded Software, Firmware, Embedded Engineer, Microcontroller
Software written for a dedicated device rather than a general-purpose computer: a car's braking unit, a pacemaker, a thermostat, a router. It runs on small chips with tight memory and power limits and often has to work for years without an update.
Think of it like
Building a watch movement instead of a desktop app: every part has to fit in a tiny case and keep ticking for years.
Junior or senior?
A distinct talent pool from web and cloud engineering, with little overlap in day-to-day skills.
Senior sounds like
Names specific chips or boards, has read hardware datasheets, and has debugged with an oscilloscope or JTAG probe as well as with code.
Ask them
“What hardware did your code run on, and how did you debug it when you couldn't just print to a screen?”
Sounds like real experience
Names specific microcontrollers or boards and describes debugging at the hardware level (logic analyser, oscilloscope, JTAG).
Probe further if
Their 'embedded' work was a Raspberry Pi running ordinary Linux and Python, which is a much lighter-weight skill set.