ESPTerm provides a simple API to remotely control and read GPIO pins GPIO2, GPIO4, and GPIO5. The main use of this API is to remotely reset a device that communicates with ESPTerm through the UART.

GPIO2 is normally used for debug UART, so when used as GPIO, debug logging is disabled. You can configure the pin functions in System Settings.

The GPIO control endpoint is `/api/v1/gpio`, with optional GET arguments:

• `do2=x` - set GPIO2 level. x can be `0`, `1`, or `t` to toggle the pin.
• `do4=x` - set GPIO4 level
• `do5=x` - set GPIO5 level
• `pulse=ms` - the command starts a pulse. After the given amount of time (milliseconds) has elapsed, the pins are set to the opposite levels than what was specified (in the case of toggle, the original pin state)

A quick example: `/api/v1/gpio?do4=1&pulse=500` sends a 500ms long positive pulse on GPIO4.

The GPIO endpoint always returns a JSON object like this: `{"io2":0,"io4":1,"io5":0}`, showing the current input levels. Input reading works always, regardless of the GPIO settings.