The WeMos D1 is a board based on the ESP8266-12E WiFi Module and that has an Arduino Layout. It is compatible with Arduino and NodeMCU.

•         Microcontroller: ESP-8266EX
•         Clock Speed 80MHz/160MHz
•         Flash: 4M bytes
•         Operating Voltage: 3.3V
•         11 Digital I/O pins
•         1 Analog Input pin
•         Arduino Compatible, you can use it on Arduino IDE.
•         OTA — Wireless Upload (Program)
•         On board switching power supply — Max 24V input, 5V 1A output