Yes, you are welcome to run a stand-alone study without subscribing to any other Ocean services (e.g., Ocean Tablets/Kiosks, Patient Messages, Website Forms). In this scenario, participants can only access the study using a public URL. All submissions via the public URL will be anonymous and do not generate a Participant Key (which is required for longitudinal research).
If you plan to perform longitudinal research by tracking study participants over time, a Participant Key is required. In this case, a subscription to an Ocean service which can collect the necessary information to generate a Participant Key (e.g., Ocean Tablets/Kiosks, Patient Messages, Website Forms) is required.