The D1 R2 is a WiFi capable ESP8266EX based development board in the form of the common Arduino UNO board format. This board is compatible with the Arduino IDE and with NodeMCU. The D1 R2 also features an on-board switching power supply which allows you to power the board from a power supply up to 12V.
*Note: The D1 R2 is a 3.3V device. If you connect it to 5V digital sensors or devices you will need a logic level converter.