esp32_riot_wifi
A small example program networking via wifi on the ESP32 using RIOT-OS with lwIP
The nice thing about the ESP32 and ESP8266 remains that you have very easy way to access the network via wifi for a microcontroller. RIOT-OS also allow you to do this but I found it quite hard to find information on it.
Thanks to some tweets with Alexandre Abadie
([https://twitter.com/alexandreabadie/status/1375854536158556167]) I
found out that the RIOT/example/paho-mqtt program can use the wifi
module from the ESP32. It uses lwIP to create a network socket and will
connect to an MQTT bridge.
This example will show you how to create activate the wifi and get a reaction back if you connect to it.
More information
RIOT documentation on ESP32
Get RIOT to compile for ESP32
The paho-mqtt examplem.