startup

Sends one message with a fixed payload each time the flow starts.

Properties

• payload type — bool, number, string or start reason. Default bool.
• value — the value to send, read as the payload type (see Typed values). Default true. Hidden with start reason.

Wiring

Input — none. startup is a source.

Output — a message with payload set to the value, topic set to an empty string, and reason saying why the flow started. With payload type start reason, the payload is that same string.

reason	the flow started because
deploy	you clicked Deploy
power_on	the board was powered up
hard_reset	the reset button was pressed
watchdog	a watchdog timer reset the board
deep_sleep	the board woke from deep sleep
soft_reset	software restarted the board, for example machine.reset()
unknown	the board can't tell

Not every board reports every reason. ESP32 boards report the reset button as power_on, because on those chips the button cuts power to the core.

Behavior

The flow starts after every deploy and each time the board starts (see Deploy), so startup fires even when the editor isn't connected. Use it for setup work, such as setting an output to a known state or drawing a first screen.

It fires once per start and never repeats. For a message you send by hand, use inject. For a repeating one, use timer.

Errors

• The value isn't a number, with payload type number. The deploy goes through; when the flow starts, the console shows a [NODE_ERROR] naming this node and startup value 'abc' is not a valid number.