21 days free. No card needed.
Staff and managers can subscribe to their shifts in the calendar they already use, including:
Your personal feed shows the shifts you are assigned to and updates as the rota changes. Google Calendar can take up to a day to refresh; most other calendars refresh more often. Managers can also subscribe to a feed of a whole workforce or a single rota.
Each feed link is private to you, and you can reset it at any time.