Seeeduino XIAO is a tiny Arduino compatible board based on Microchip's ARM Cortex-M0+ MCU. Measuring just 2x1.7x0.35 cm, it is low power, comes with 11 GPIO pins and a big features pack, thus making it almost perfect for many IoT/WoT projects.

As opposed to the less powerful Arduino, the competitively priced and WiFi-enabled ESP8266 supports the Web-of-Things (WoT) since it can be programmed in JavaScript.