He was one of the early adopters of the ESP8266 and wrote a bunch of very interesting firware for those (like the ability for it to act as an AP to set up WiFi credentials without additional hardware.

He was subsequently hired to as a software engineering manager and technical marketing manager at Espressif, who were working on the ESP32 at the time.

I enjoyed Jeroen's recent appearance on the Amp Hour podcast where he talks about a lot of this: https://theamphour.com/359-an-interview-with-jeroen-domburg-...