Arduino is an open source hardware platform that runs a rather odd variant of C in which you define two functions---a function that runs at startup, and a function that runs repeatedly.
Other options include running CircuitPython.
- https://www.arduino.cc — Marketplace
- Adafruit HUZZAH ESP8266 Breakout $9.95
- Adafruit Feather HUZZAH with ESP8266 WiFi $15.95
LED Protocol: neopixel: