The “ESP32 IoT Relay Board” is a credit card-sized ESP32 board with four small 250VAC/30VDC 7A relays that runs Tasmota open-source firmware and supports Alexa & Google Assistant for voice control.

A teardown of the device reveals a XIAO-ESP32C3 module with an ESP32-C3 chip acting as the central controller. On the other side, you’ll see the small HLK-5M05 power module and two HF35F-L 10A 250VAC ...