ESP8266 ESP-01 Module pinout

 

When you buy an ESP-01 module from local market you might not find datasheet and pin out for the same. Fortunately for ESP8266, there is a huge community which helps but that is not the case with many devices. Here is the pinout of the ESP-01 module,

Remember that the VCC supported is 3.3V. so, if you are connecting a Host board with 5V output, you need to have a level translator. The TXD and RXD pins are used to connect to the host controller board.