The ESP-12S is a WiFi module based on ESP8266, with built-in 32Mbit Flash, in the small SMD16 package. There’re also onboard PCB antenna and metal shield. In short, it’s a small form factor and fairly high cost effective WiFi module.

With the pre-flashed AT firmware, you can control the module through UART AT commands easily. The module integrates MCU inside, supports other developments like Lua/Micropython/Arduino to achieve flexible and fast prototyping, make it easy to integrate the module into IoT applications.