ESP8266EX-WiFi-MOD ESP-12E is the development board for ESP8266EX with UART0, GPIOs and ADC pin exposed. Can be soldered to PCB or used with 2mm pin headers.
Tensilica L106 low power 32-bit MCU that can run at up 160MHz
GPIO x16 (up to 5 used for interface with flash)
all RF components
WiFi baseband, MAC, TCP/IP
advance standby and sleep modes
SPI / UART / SDIO connectivity
Note: On bottom row are exposed SPI Flash pins. They can’t be used as application (GPIO) pins.