# Patient App
One of dot.base's most interesting features is its ability to seamlessly interact with the patient app "dot.link" for iOS and Android to record patient-reported outcomes and sensor data in a GDPR-compliant way.
As with all other dot.base services, the dot.link app is also based on FHIR. It allows you to display any kind of FHIR Questionnaires (opens new window) and to collect patient answers using a corresponding FHIR QuestionnaireResponse (opens new window).
Using this concept, patients have one app for all study or treatment contexts. New questionnaires to report patient-reported outcomes can just easily be provided without any technical adjustments or developer's work.
To ensure a high level of data protection, the app does not store any identifying data of the patient at any time. Its authentication workflow is based on Time-based-One-Time-Password (opens new window) instead. Thus, patients don't have to reveal their personal email addresses. They are just linked to their health record through scanning a QR-Code.
Setting up patient questionnaires works as follows:
- Use the drag and drop form builder to create FHIR Questionnaires and bundle them into a set.
- Set a time window for filling in the questionnaire response in the app.
- Set the number of repetitions of the questionnaire (if needed) and the time of the last repetition.
- Set up authentication for a patient
- Assign a set of questionnaires to a patient
- View the patient's answers using dot.base's medical dashboard