Adafruit 2821 Feather Huzzah with ESP8266 Wi-Fi;

At the feather huzzah's heart is an ESP8266 WiFi microcontroller clocked at 80 MHz and at 3.3V logic. This controller contains a tensile chip core as well as a full WiFi stack. You can program the controller using the arduino ide for an easy-to-run Internet of things core. We wired up a high-quality silabs Cp2104 usb-serial chip that an upload Code at a blistering 921, 600 Baud for fast development time. It also has auto-reset so no fiddling with pins and reset buttons. The Cp2104 has better driver support than the CH340 and can do very high speeds without stability issues. To make it easy to use for portable projects, we added a connector for any of our 3.7V lithium polymer batteries and built in battery charging. You don't need a battery, for it will run just fine straight from the Micro USB connector. But If you do have a battery, you can take it on the go, and plug in the USB to recharge. The feather will automatically switch over to USB power when it's available.