INSTALL ESP8266 ON ARDUINO IDE

To install  ESP8266 on Arduino IDE,  you need to follow these instructions

1. Open the preferences window from the Arduino IDE.
   Go to: File > Preferences
2. Copy this URL “http://arduino.esp8266.com/stable/package_esp8266com_index.json” and paste into the “Additional Board Manager URLs” field as shown in the figure below. Then, click the “OK” button.

   

3. Open boards manager.
   Go to: Tools > Board > Boards Manager

   

4. Scroll down or search in search bar “ESP8266” and Install “esp8266 by ESP8266 Community”. Then wait for few minutes to get it installed.
   
   Note: You need Internet connection while file gets download
   
   

   

5. After download you can see different boards are now available in Go to: Tools > Board
   

   

6. Select the board you are using, for NodeMCU you can select
   • NodeMCU 0.9 (ESP-12 MODULE) or
   • NodeMCU 1.0 (ESP-12E MODULE)