openapi: 3.0.3
info:
  title: Castor EDC / CDMS API
  description: >-
    The Castor EDC / CDMS API is a RESTful interface to Castor's cloud electronic
    data capture (EDC) and clinical data management platform. It exposes study
    configuration and collected data - studies, participants (records), institutes
    (sites), users, fields and field metadata, study data points, repeating data
    (reports), surveys and survey packages, the audit trail, and batch data export.
    Authentication is OAuth2 with the Client Credentials flow: request an access
    token from POST /oauth/token using an API Client ID and Client Secret generated
    in Castor User Settings, then send it as a Bearer token. Access tokens are valid
    for 5 hours. Most identifiers (study, field, report / repeating-data instance,
    survey package instance) are uppercase GUIDs in 8-4-4-4-12 format; the
    participant ID is the exception.


    Endpoint status: paths that this document marks with `x-endpoint-status:
    confirmed` were observed directly in Castor's published API reference and
    helpdesk documentation. Paths marked `x-endpoint-status: modeled` reflect the
    documented resource model and the coverage of the official R and Python wrapper
    packages, but the exact path or shape was inferred and should be verified
    against https://data.castoredc.com/api during reconciliation.
  version: '1.0'
  contact:
    name: Castor
    url: https://www.castoredc.com
  license:
    name: Proprietary
    url: https://www.castoredc.com/legal/
servers:
  - url: https://data.castoredc.com/api
    description: Castor EU (default)
  - url: https://us.castoredc.com/api
    description: Castor US region
security:
  - oauth2ClientCredentials: []
tags:
  - name: Studies
    description: Studies accessible to the API client.
  - name: Participants
    description: Participants (records / subjects) enrolled in a study.
  - name: Institutes
    description: Institutes (sites / centers) participating in a study.
  - name: Users
    description: Users and study membership.
  - name: Fields
    description: Study fields and their metadata (dependencies, option groups, validations).
  - name: Study Data Points
    description: Collected values for study forms.
  - name: Reports
    description: Reports / repeating data and their instances.
  - name: Surveys
    description: Surveys, survey packages, and ePRO.
  - name: Audit Trail
    description: Immutable audit trail of study changes.
  - name: Data Export
    description: Bulk export of study data, structure, and option groups.
  - name: Metadata
    description: Reference metadata such as countries.
paths:
  /oauth/token:
    post:
      operationId: getAccessToken
      tags:
        - Studies
      summary: Obtain an OAuth2 access token
      description: >-
        Exchange an API Client ID and Client Secret for a Bearer access token using
        the client_credentials grant. The returned token is valid for 5 hours.
      security: []
      x-endpoint-status: confirmed
      requestBody:
        required: true
        content:
          application/x-www-form-urlencoded:
            schema:
              type: object
              required:
                - client_id
                - client_secret
                - grant_type
              properties:
                client_id:
                  type: string
                client_secret:
                  type: string
                grant_type:
                  type: string
                  enum:
                    - client_credentials
      responses:
        '200':
          description: An access token.
          content:
            application/json:
              schema:
                type: object
                properties:
                  access_token:
                    type: string
                  token_type:
                    type: string
                    example: Bearer
                  expires_in:
                    type: integer
                    example: 18000
        '401':
          $ref: '#/components/responses/Unauthorized'
  /study:
    get:
      operationId: listStudies
      tags:
        - Studies
      summary: List studies
      description: Lists all studies the authenticated API client has access to.
      x-endpoint-status: confirmed
      parameters:
        - $ref: '#/components/parameters/Page'
      responses:
        '200':
          description: A paginated list of studies.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/StudyCollection'
        '401':
          $ref: '#/components/responses/Unauthorized'
  /study/{study_id}:
    get:
      operationId: getStudy
      tags:
        - Studies
      summary: Retrieve a study
      description: Retrieves a single study by its GUID.
      x-endpoint-status: confirmed
      parameters:
        - $ref: '#/components/parameters/StudyId'
      responses:
        '200':
          description: A study.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Study'
        '401':
          $ref: '#/components/responses/Unauthorized'
        '404':
          $ref: '#/components/responses/NotFound'
  /study/{study_id}/participant:
    get:
      operationId: listParticipants
      tags:
        - Participants
      summary: List participants
      description: Lists the participants (records) enrolled in a study.
      x-endpoint-status: confirmed
      parameters:
        - $ref: '#/components/parameters/StudyId'
        - $ref: '#/components/parameters/Page'
      responses:
        '200':
          description: A paginated list of participants.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ParticipantCollection'
        '401':
          $ref: '#/components/responses/Unauthorized'
    post:
      operationId: createParticipant
      tags:
        - Participants
      summary: Create a participant
      description: Creates a new participant (record) in a study.
      x-endpoint-status: confirmed
      parameters:
        - $ref: '#/components/parameters/StudyId'
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/ParticipantInput'
      responses:
        '201':
          description: The created participant.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Participant'
        '401':
          $ref: '#/components/responses/Unauthorized'
  /study/{study_id}/participant/{participant_id}:
    get:
      operationId: getParticipant
      tags:
        - Participants
      summary: Retrieve a participant
      description: Retrieves a single participant by ID.
      x-endpoint-status: confirmed
      parameters:
        - $ref: '#/components/parameters/StudyId'
        - $ref: '#/components/parameters/ParticipantId'
      responses:
        '200':
          description: A participant.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Participant'
        '404':
          $ref: '#/components/responses/NotFound'
  /study/{study_id}/institute:
    get:
      operationId: listInstitutes
      tags:
        - Institutes
      summary: List institutes
      description: Lists the institutes (sites) participating in a study.
      x-endpoint-status: confirmed
      parameters:
        - $ref: '#/components/parameters/StudyId'
      responses:
        '200':
          description: A list of institutes.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/InstituteCollection'
        '401':
          $ref: '#/components/responses/Unauthorized'
    post:
      operationId: createInstitute
      tags:
        - Institutes
      summary: Create an institute
      description: Creates a new institute (site) in a study.
      x-endpoint-status: modeled
      parameters:
        - $ref: '#/components/parameters/StudyId'
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/InstituteInput'
      responses:
        '201':
          description: The created institute.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Institute'
  /study/{study_id}/institute/{institute_id}:
    get:
      operationId: getInstitute
      tags:
        - Institutes
      summary: Retrieve an institute
      description: Retrieves a single institute by ID.
      x-endpoint-status: confirmed
      parameters:
        - $ref: '#/components/parameters/StudyId'
        - $ref: '#/components/parameters/InstituteId'
      responses:
        '200':
          description: An institute.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Institute'
        '404':
          $ref: '#/components/responses/NotFound'
  /user:
    get:
      operationId: listUsers
      tags:
        - Users
      summary: List users
      description: Lists the users the authenticated account can access.
      x-endpoint-status: confirmed
      responses:
        '200':
          description: A list of users.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/UserCollection'
        '401':
          $ref: '#/components/responses/Unauthorized'
  /user/{user_id}:
    get:
      operationId: getUser
      tags:
        - Users
      summary: Retrieve a user
      description: Retrieves a single user by ID.
      x-endpoint-status: confirmed
      parameters:
        - $ref: '#/components/parameters/UserId'
      responses:
        '200':
          description: A user.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/User'
        '404':
          $ref: '#/components/responses/NotFound'
  /study/{study_id}/user:
    get:
      operationId: listStudyUsers
      tags:
        - Users
      summary: List study users
      description: Lists the users who are members of a given study.
      x-endpoint-status: confirmed
      parameters:
        - $ref: '#/components/parameters/StudyId'
      responses:
        '200':
          description: A list of study users.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/UserCollection'
  /study/{study_id}/field:
    get:
      operationId: listFields
      tags:
        - Fields
      summary: List fields
      description: Lists all data-capture fields defined in a study.
      x-endpoint-status: confirmed
      parameters:
        - $ref: '#/components/parameters/StudyId'
        - $ref: '#/components/parameters/Page'
      responses:
        '200':
          description: A paginated list of fields.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/FieldCollection'
        '401':
          $ref: '#/components/responses/Unauthorized'
  /study/{study_id}/field/{field_id}:
    get:
      operationId: getField
      tags:
        - Fields
      summary: Retrieve a field
      description: Retrieves a single field by ID.
      x-endpoint-status: confirmed
      parameters:
        - $ref: '#/components/parameters/StudyId'
        - $ref: '#/components/parameters/FieldId'
      responses:
        '200':
          description: A field.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Field'
        '404':
          $ref: '#/components/responses/NotFound'
  /study/{study_id}/field-dependency:
    get:
      operationId: listFieldDependencies
      tags:
        - Fields
      summary: List field dependencies
      description: Lists conditional-logic dependencies between fields in a study.
      x-endpoint-status: confirmed
      parameters:
        - $ref: '#/components/parameters/StudyId'
      responses:
        '200':
          description: A list of field dependencies.
          content:
            application/json:
              schema:
                type: object
  /study/{study_id}/field-optiongroup:
    get:
      operationId: listFieldOptionGroups
      tags:
        - Fields
      summary: List field option groups
      description: Lists the option groups (answer choices) used by fields in a study.
      x-endpoint-status: confirmed
      parameters:
        - $ref: '#/components/parameters/StudyId'
      responses:
        '200':
          description: A list of option groups.
          content:
            application/json:
              schema:
                type: object
  /study/{study_id}/field-validation:
    get:
      operationId: listFieldValidations
      tags:
        - Fields
      summary: List field validations
      description: Lists validation rules attached to fields in a study.
      x-endpoint-status: modeled
      parameters:
        - $ref: '#/components/parameters/StudyId'
      responses:
        '200':
          description: A list of field validations.
          content:
            application/json:
              schema:
                type: object
  /study/{study_id}/data-points/study:
    get:
      operationId: listStudyDataPoints
      tags:
        - Study Data Points
      summary: List all study data points
      description: Retrieves all study-form data points collected across a study.
      x-endpoint-status: confirmed
      parameters:
        - $ref: '#/components/parameters/StudyId'
        - $ref: '#/components/parameters/Page'
      responses:
        '200':
          description: A paginated list of study data points.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/DataPointCollection'
  /study/{study_id}/participant/{participant_id}/data-points/study:
    get:
      operationId: listParticipantStudyDataPoints
      tags:
        - Study Data Points
      summary: List a participant's study data points
      description: Retrieves the study-form data points for a single participant.
      x-endpoint-status: confirmed
      parameters:
        - $ref: '#/components/parameters/StudyId'
        - $ref: '#/components/parameters/ParticipantId'
      responses:
        '200':
          description: A list of study data points.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/DataPointCollection'
    post:
      operationId: updateParticipantStudyDataPoints
      tags:
        - Study Data Points
      summary: Create or update a participant's study data points
      description: >-
        Creates or updates study-form data points for a single participant. Accepts
        a batch of field_id / value pairs.
      x-endpoint-status: confirmed
      parameters:
        - $ref: '#/components/parameters/StudyId'
        - $ref: '#/components/parameters/ParticipantId'
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/DataPointWriteRequest'
      responses:
        '200':
          description: The updated data points.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/DataPointCollection'
  /study/{study_id}/report:
    get:
      operationId: listReports
      tags:
        - Reports
      summary: List reports (repeating data)
      description: Lists the report / repeating-data definitions configured in a study.
      x-endpoint-status: confirmed
      parameters:
        - $ref: '#/components/parameters/StudyId'
      responses:
        '200':
          description: A list of reports.
          content:
            application/json:
              schema:
                type: object
  /study/{study_id}/report/{report_id}:
    get:
      operationId: getReport
      tags:
        - Reports
      summary: Retrieve a report
      description: Retrieves a single report / repeating-data definition by ID.
      x-endpoint-status: modeled
      parameters:
        - $ref: '#/components/parameters/StudyId'
        - name: report_id
          in: path
          required: true
          schema:
            type: string
      responses:
        '200':
          description: A report.
          content:
            application/json:
              schema:
                type: object
  /study/{study_id}/participant/{participant_id}/data-points/repeating-data-instance:
    get:
      operationId: listRepeatingDataInstances
      tags:
        - Reports
      summary: List a participant's repeating-data instances
      description: Retrieves the repeating-data (report) instances for a participant.
      x-endpoint-status: confirmed
      parameters:
        - $ref: '#/components/parameters/StudyId'
        - $ref: '#/components/parameters/ParticipantId'
      responses:
        '200':
          description: A list of repeating-data instances.
          content:
            application/json:
              schema:
                type: object
  /study/{study_id}/participant/{participant_id}/data-points/repeating-data-instance/{repeating_data_instance_id}:
    post:
      operationId: updateRepeatingDataInstance
      tags:
        - Reports
      summary: Update a repeating-data instance's data points
      description: Creates or updates the data points of a repeating-data instance.
      x-endpoint-status: confirmed
      parameters:
        - $ref: '#/components/parameters/StudyId'
        - $ref: '#/components/parameters/ParticipantId'
        - name: repeating_data_instance_id
          in: path
          required: true
          schema:
            type: string
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/DataPointWriteRequest'
      responses:
        '200':
          description: The updated data points.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/DataPointCollection'
  /study/{study_id}/survey:
    get:
      operationId: listSurveys
      tags:
        - Surveys
      summary: List surveys
      description: Lists the survey and ePRO definitions configured in a study.
      x-endpoint-status: confirmed
      parameters:
        - $ref: '#/components/parameters/StudyId'
      responses:
        '200':
          description: A list of surveys.
          content:
            application/json:
              schema:
                type: object
  /study/{study_id}/participant/{participant_id}/data-points/survey-instance:
    get:
      operationId: listSurveyInstances
      tags:
        - Surveys
      summary: List a participant's survey instances
      description: Retrieves the survey instances (and their data points) for a participant.
      x-endpoint-status: confirmed
      parameters:
        - $ref: '#/components/parameters/StudyId'
        - $ref: '#/components/parameters/ParticipantId'
      responses:
        '200':
          description: A list of survey instances.
          content:
            application/json:
              schema:
                type: object
  /study/{study_id}/participant/{participant_id}/data-points/survey-package-instance:
    post:
      operationId: createSurveyPackageInstance
      tags:
        - Surveys
      summary: Send a survey package to a participant
      description: >-
        Creates a survey-package instance, sending one or more surveys to a
        participant (for example, by email invitation).
      x-endpoint-status: confirmed
      parameters:
        - $ref: '#/components/parameters/StudyId'
        - $ref: '#/components/parameters/ParticipantId'
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
              properties:
                survey_package_id:
                  type: string
                email_address:
                  type: string
      responses:
        '201':
          description: The created survey-package instance.
          content:
            application/json:
              schema:
                type: object
  /study/{study_id}/compliance:
    post:
      operationId: getSurveyCompliance
      tags:
        - Surveys
      summary: Retrieve participant survey compliance
      description: Returns survey compliance information for participants in a study.
      x-endpoint-status: confirmed
      parameters:
        - $ref: '#/components/parameters/StudyId'
      responses:
        '200':
          description: Survey compliance information.
          content:
            application/json:
              schema:
                type: object
  /study/{study_id}/audit-trail:
    get:
      operationId: getAuditTrail
      tags:
        - Audit Trail
      summary: Retrieve the audit trail
      description: >-
        Retrieves audit trail entries for a study - every data and configuration
        change, with actor and timestamp. Supports date range filtering.
      x-endpoint-status: confirmed
      parameters:
        - $ref: '#/components/parameters/StudyId'
        - name: date_from
          in: query
          schema:
            type: string
            format: date
        - name: date_to
          in: query
          schema:
            type: string
            format: date
        - $ref: '#/components/parameters/Page'
      responses:
        '200':
          description: A paginated list of audit trail entries.
          content:
            application/json:
              schema:
                type: object
  /study/{study_id}/export/data:
    get:
      operationId: exportStudyData
      tags:
        - Data Export
      summary: Export study data
      description: Exports the collected data of a study (CSV).
      x-endpoint-status: confirmed
      parameters:
        - $ref: '#/components/parameters/StudyId'
      responses:
        '200':
          description: The exported study data.
          content:
            text/csv:
              schema:
                type: string
  /study/{study_id}/export/structure:
    get:
      operationId: exportStudyStructure
      tags:
        - Data Export
      summary: Export study structure
      description: Exports the structure (forms, fields, phases) of a study.
      x-endpoint-status: confirmed
      parameters:
        - $ref: '#/components/parameters/StudyId'
      responses:
        '200':
          description: The exported study structure.
          content:
            text/csv:
              schema:
                type: string
  /study/{study_id}/export/optiongroups:
    get:
      operationId: exportOptionGroups
      tags:
        - Data Export
      summary: Export option groups
      description: Exports the option groups (answer choices) of a study.
      x-endpoint-status: confirmed
      parameters:
        - $ref: '#/components/parameters/StudyId'
      responses:
        '200':
          description: The exported option groups.
          content:
            text/csv:
              schema:
                type: string
  /country:
    get:
      operationId: listCountries
      tags:
        - Metadata
      summary: List countries
      description: Lists all countries known to Castor (reference metadata).
      x-endpoint-status: confirmed
      responses:
        '200':
          description: A list of countries.
          content:
            application/json:
              schema:
                type: object
  /country/{country_id}:
    get:
      operationId: getCountry
      tags:
        - Metadata
      summary: Retrieve a country
      description: Retrieves a single country by ID.
      x-endpoint-status: confirmed
      parameters:
        - name: country_id
          in: path
          required: true
          schema:
            type: string
      responses:
        '200':
          description: A country.
          content:
            application/json:
              schema:
                type: object
components:
  securitySchemes:
    oauth2ClientCredentials:
      type: oauth2
      flows:
        clientCredentials:
          tokenUrl: https://data.castoredc.com/api/oauth/token
          scopes: {}
  parameters:
    StudyId:
      name: study_id
      in: path
      required: true
      description: The study GUID (uppercase, 8-4-4-4-12 format).
      schema:
        type: string
    ParticipantId:
      name: participant_id
      in: path
      required: true
      description: The participant (record) ID.
      schema:
        type: string
    InstituteId:
      name: institute_id
      in: path
      required: true
      description: The institute GUID.
      schema:
        type: string
    FieldId:
      name: field_id
      in: path
      required: true
      description: The field GUID.
      schema:
        type: string
    UserId:
      name: user_id
      in: path
      required: true
      description: The user GUID.
      schema:
        type: string
    Page:
      name: page
      in: query
      required: false
      description: Page number for paginated (HAL) collections.
      schema:
        type: integer
        minimum: 1
  responses:
    Unauthorized:
      description: Missing or invalid access token.
    NotFound:
      description: The requested resource was not found.
  schemas:
    Study:
      type: object
      properties:
        study_id:
          type: string
          format: uuid
        name:
          type: string
        created_by:
          type: string
        live:
          type: boolean
        randomization_enabled:
          type: boolean
        surveys_enabled:
          type: boolean
        created_on:
          type: string
          format: date-time
    StudyCollection:
      type: object
      properties:
        _embedded:
          type: object
          properties:
            study:
              type: array
              items:
                $ref: '#/components/schemas/Study'
        page_count:
          type: integer
        total_items:
          type: integer
    ParticipantInput:
      type: object
      properties:
        participant_id:
          type: string
        institute_id:
          type: string
          format: uuid
        email_address:
          type: string
    Participant:
      allOf:
        - $ref: '#/components/schemas/ParticipantInput'
        - type: object
          properties:
            status:
              type: string
            randomized_id:
              type: string
            progress:
              type: integer
            created_on:
              type: string
              format: date-time
    ParticipantCollection:
      type: object
      properties:
        _embedded:
          type: object
          properties:
            participants:
              type: array
              items:
                $ref: '#/components/schemas/Participant'
        page_count:
          type: integer
        total_items:
          type: integer
    InstituteInput:
      type: object
      properties:
        name:
          type: string
        abbreviation:
          type: string
        country_id:
          type: integer
    Institute:
      allOf:
        - $ref: '#/components/schemas/InstituteInput'
        - type: object
          properties:
            institute_id:
              type: string
              format: uuid
            code:
              type: string
    InstituteCollection:
      type: object
      properties:
        _embedded:
          type: object
          properties:
            institutes:
              type: array
              items:
                $ref: '#/components/schemas/Institute'
    User:
      type: object
      properties:
        id:
          type: string
          format: uuid
        name:
          type: string
        email_address:
          type: string
        institute:
          type: string
    UserCollection:
      type: object
      properties:
        _embedded:
          type: object
          properties:
            user:
              type: array
              items:
                $ref: '#/components/schemas/User'
    Field:
      type: object
      properties:
        id:
          type: string
          format: uuid
        field_id:
          type: string
          format: uuid
        field_variable_name:
          type: string
        field_label:
          type: string
        field_type:
          type: string
        field_required:
          type: boolean
        option_group:
          type: string
    FieldCollection:
      type: object
      properties:
        _embedded:
          type: object
          properties:
            fields:
              type: array
              items:
                $ref: '#/components/schemas/Field'
        page_count:
          type: integer
        total_items:
          type: integer
    DataPoint:
      type: object
      properties:
        field_id:
          type: string
          format: uuid
        field_value:
          type: string
        participant_id:
          type: string
        updated_on:
          type: string
          format: date-time
    DataPointCollection:
      type: object
      properties:
        _embedded:
          type: object
          properties:
            items:
              type: array
              items:
                $ref: '#/components/schemas/DataPoint'
        page_count:
          type: integer
        total_items:
          type: integer
    DataPointWriteRequest:
      type: object
      required:
        - data
      properties:
        common:
          type: object
          properties:
            change_reason:
              type: string
        data:
          type: array
          items:
            type: object
            properties:
              field_id:
                type: string
                format: uuid
              field_value:
                type: string