Fitbit

Fitbit Heart Rate API

Retrieve heart rate time series including resting heart rate, custom and default heart rate zones, and zone-minute breakdowns. Intraday endpoints expose 1-second, 1-minute, 5-minute, or 15-minute detail-level series and require explicit Intraday access approval.

Fitbit Heart Rate API is one of 12 APIs that Fitbit publishes on the APIs.io network, described by a machine-readable OpenAPI specification.

This API exposes 1 machine-runnable capability that can be deployed as REST, MCP, or Agent Skill surfaces via Naftiko.

Tagged areas include Heart Rate, Cardiovascular, and Wearable. The published artifact set on APIs.io includes API documentation, an OpenAPI specification, and 1 Naftiko capability spec.

Documentation GitHub OpenAPI

OpenAPI Specification

openapi: 3.0.3
info:
  title: Fitbit Heart Rate API
  description: |
    Read user heart rate data from Fitbit. Provides resting heart rate, heart
    rate zones, and time-series heart rate measurements at day, week, month, and
    year granularity. Intraday endpoints expose 1-minute or 1-second detail-level
    series and require explicit Intraday access approval from Fitbit/Google.
  version: '1'
  contact:
    name: Fitbit Developer
    url: https://dev.fitbit.com/build/reference/web-api/heartrate-timeseries/
servers:
- url: https://api.fitbit.com
security:
- OAuth2:
  - heartrate
paths:
  /1/user/{user-id}/activities/heart/date/{date}/{period}.json:
    get:
      summary: Get Heart Rate Time Series By Date
      description: Retrieves a user's heart rate time series for the given date and period.
      operationId: getHeartRateTimeSeriesByDate
      parameters:
      - $ref: '#/components/parameters/UserId'
      - name: date
        in: path
        required: true
        schema:
          type: string
      - name: period
        in: path
        required: true
        schema:
          type: string
          enum: [1d, 7d, 30d, 1w, 1m]
      responses:
        '200':
          description: Heart rate time series.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/HeartRateTimeSeries'
  /1/user/{user-id}/activities/heart/date/{base-date}/{end-date}.json:
    get:
      summary: Get Heart Rate Time Series By Date Range
      description: Retrieves a user's heart rate time series for the given date range.
      operationId: getHeartRateTimeSeriesByDateRange
      parameters:
      - $ref: '#/components/parameters/UserId'
      - name: base-date
        in: path
        required: true
        schema:
          type: string
      - name: end-date
        in: path
        required: true
        schema:
          type: string
      responses:
        '200':
          description: Heart rate time series.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/HeartRateTimeSeries'
  /1/user/{user-id}/activities/heart/date/{date}/1d/{detail-level}.json:
    get:
      summary: Get Heart Rate Intraday Time Series
      description: Retrieves the user's heart rate intraday time series at the requested detail level (1sec, 1min, 5min, or 15min). Requires Intraday access.
      operationId: getHeartRateIntradayTimeSeries
      parameters:
      - $ref: '#/components/parameters/UserId'
      - name: date
        in: path
        required: true
        schema:
          type: string
      - name: detail-level
        in: path
        required: true
        schema:
          type: string
          enum: [1sec, 1min, 5min, 15min]
      responses:
        '200':
          description: Heart rate intraday data.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/HeartRateIntraday'
components:
  parameters:
    UserId:
      name: user-id
      in: path
      required: true
      schema:
        type: string
        default: '-'
  securitySchemes:
    OAuth2:
      type: oauth2
      flows:
        authorizationCode:
          authorizationUrl: https://www.fitbit.com/oauth2/authorize
          tokenUrl: https://api.fitbit.com/oauth2/token
          scopes:
            heartrate: Heart rate data
  schemas:
    HeartRateTimeSeries:
      type: object
      properties:
        activities-heart:
          type: array
          items:
            type: object
            properties:
              dateTime:
                type: string
                format: date
              value:
                type: object
                properties:
                  customHeartRateZones:
                    type: array
                    items:
                      $ref: '#/components/schemas/HeartRateZone'
                  heartRateZones:
                    type: array
                    items:
                      $ref: '#/components/schemas/HeartRateZone'
                  restingHeartRate:
                    type: integer
    HeartRateZone:
      type: object
      properties:
        caloriesOut:
          type: number
        max:
          type: integer
        min:
          type: integer
        minutes:
          type: integer
        name:
          type: string
    HeartRateIntraday:
      type: object
      properties:
        activities-heart-intraday:
          type: object
          properties:
            dataset:
              type: array
              items:
                type: object
                properties:
                  time:
                    type: string
                  value:
                    type: integer
            datasetInterval:
              type: integer
            datasetType:
              type: string

Fitbit Heart Rate API

Documentation

Specifications

Other Resources

OpenAPI Specification