Dexcom Data Range API

openapi: 3.0.3
info:
  title: Dexcom Developer Alerts Data Range API
  version: v3
  description: The Dexcom Developer API provides authorized third-party applications with read access to a Dexcom user's continuous glucose monitoring (CGM) data. Resources include estimated glucose values (EGVs), calibrations, events, alerts, devices, and data range. The API uses OAuth 2.0 authorization code flow and exposes separate sandbox and production environments.
  contact:
    name: Dexcom Developer Program
    url: https://developer.dexcom.com/
  termsOfService: https://developer.dexcom.com/terms-of-use
  x-generated-from: documentation
  x-source-url: https://developer.dexcom.com/docs/dexcomv3/endpoint-overview
  x-last-validated: '2026-05-05'
servers:
- url: https://api.dexcom.com
  description: Production (United States)
- url: https://api.dexcom.eu
  description: Production (Europe / International)
- url: https://api.dexcom.jp
  description: Production (Japan)
- url: https://sandbox-api.dexcom.com
  description: Sandbox (Development)
security:
- OAuth2: []
tags:
- name: Data Range
  description: Earliest and latest record times available for the authorized user.
paths:
  /v3/users/self/dataRange:
    get:
      tags:
      - Data Range
      operationId: getDataRangeV3
      summary: Get Data Range
      description: Retrieve the earliest and latest record timestamps available for the authorized user across calibrations, EGVs, and events. Use this to efficiently page historical data and to determine when new data is available.
      parameters:
      - name: lastSyncTime
        in: query
        required: false
        description: Optional ISO 8601 timestamp; the response only reflects records updated since this time.
        schema:
          type: string
          format: date-time
      responses:
        '200':
          description: Data range retrieved successfully.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/DataRangeResponse'
              examples:
                GetDataRangeV3200Example:
                  summary: Default getDataRangeV3 200 response
                  x-microcks-default: true
                  value:
                    recordType: dataRange
                    recordVersion: '3.0'
                    userId: 35d77a14-243f-4d5d-9f3f-3b3a7d7e9c3a
                    calibrations:
                      start:
                        systemTime: '2026-01-15T08:32:11'
                        displayTime: '2026-01-15T01:32:11'
                      end:
                        systemTime: '2026-04-30T19:18:24'
                        displayTime: '2026-04-30T12:18:24'
                    egvs:
                      start:
                        systemTime: '2026-01-15T08:00:00'
                        displayTime: '2026-01-15T01:00:00'
                      end:
                        systemTime: '2026-04-30T23:55:00'
                        displayTime: '2026-04-30T16:55:00'
                    events:
                      start:
                        systemTime: '2026-01-15T09:14:02'
                        displayTime: '2026-01-15T02:14:02'
                      end:
                        systemTime: '2026-04-29T17:42:55'
                        displayTime: '2026-04-29T10:42:55'
      x-microcks-operation:
        delay: 0
        dispatcher: FALLBACK
components:
  schemas:
    DataRangeResponse:
      type: object
      properties:
        recordType:
          type: string
          example: dataRange
        recordVersion:
          type: string
          example: '3.0'
        userId:
          type: string
        calibrations:
          $ref: '#/components/schemas/DataRangeWindow'
        egvs:
          $ref: '#/components/schemas/DataRangeWindow'
        events:
          $ref: '#/components/schemas/DataRangeWindow'
    DateTime:
      type: string
      format: date-time
      description: ISO 8601 timestamp.
    DataRangeWindow:
      type: object
      properties:
        start:
          $ref: '#/components/schemas/DataRangeMoment'
        end:
          $ref: '#/components/schemas/DataRangeMoment'
    DataRangeMoment:
      type: object
      properties:
        systemTime:
          $ref: '#/components/schemas/DateTime'
        displayTime:
          $ref: '#/components/schemas/DateTime'
      required:
      - systemTime
      - displayTime
  securitySchemes:
    OAuth2:
      type: oauth2
      description: Dexcom uses OAuth 2.0 authorization code flow. The only acceptable scope value is `offline_access`.
      flows:
        authorizationCode:
          authorizationUrl: https://api.dexcom.com/v2/oauth2/login
          tokenUrl: https://api.dexcom.com/v2/oauth2/token
          refreshUrl: https://api.dexcom.com/v2/oauth2/token
          scopes:
            offline_access: Long-lived access to the user's CGM data via refresh tokens.