NOTE: This documentation is not yet complete. APIs are in active development.

A Bridge app can be used to run one or more studies, which may have overlapping or discrete participants. Each study is sponsored by one or more organizations, and the administrative accounts for that organization will have privileged access to work with the study.


A user must create an account in Bridge before they can be enrolled in a study. There are two ways to be enrolled in a study:

  1. The user can consent to participate to a consent that will enroll them in a specific study;
  2. A study administrator can create StudyParticipant that includes an enrollment property with an Enrollment object. This will enroll the account in a study at the same time as it is created. The Enrollment must include the study ID and may optionally include an external ID;
  3. A study administrator can manually enroll an existing participant, optionally providing an external ID to identify the participant in the study.

In the second two cases where a user is not enrolling themself, researchers must be sure they have acquired informed consent from the participant outside of Bridge.

Enrollments can be enumerated for a study (including the number of participants who have withdrawn from the study). Users can withdraw from a study or withdraw from all studies in an app.

In the user’s session, enrollments are given with the following JSON through two read-only properties, studyIds and externalIds:

  "studyIds": ["study1", "study2"],
  "externalIds": {
    "study1": "externalId1",
    "study2": "externalId2"
  "type": "UserSessionInfo"

External IDs

You may wish to create accounts that are only identified by an identifier that you create and manage outside of Bridge. External IDs are application scoped and must be associated to a study in that app. The External identifiers APIs allow you to create and enumerate accounts using only an ExternalIdentifier object.

How will your participant authenticate with Bridge if you use an external ID? You will make it harder for the user to participate in your study if you do not collect a phone number or email address to use as a delivery method to sign in the user. The participant could use a password, but this needs to be set when the account is created given the fact that there is no way to send a *change of password* email to a user without an email address.