Call to action and OnTick

Can the algo engine be run by an update in external data or only on a new tick event?

I intend to use an API to receive external data and want this external data receipt to be the action trigger to the algo running.

So I want the action to be:

- new external data received via API

- algo runs

- algo places orders irrelevant of whether a new tick is received

As opposed to:

- new external data received

- algo remains silent

- new tick received

- algo runs

- algo places orders irrelevant of whether a new tick is received

Thanks.