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FitbitAPI provides a Ruby interface to the Fitbit Web API.


To install the latest release:

$ gem install fitbit_api

To include in a Rails project, add it to the Gemfile:

gem 'fitbit_api'

Getting Started

To use the Fitbit API, you must register your application at After registering, you should have access to the CLIENT ID and CLIENT SECRET values for use in instantiating a FitbitAPI::Client object.


You can reference the fitbit_api_rails repo as a simple example of how to use this gem within a Rails project.


If you already have a user's token data and Fitbit user_id:

client = 'XXXXXX',
                               client_secret: 'xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx',
                               access_token: 'xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx',
                               refresh_token: 'xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx',
                               expires_at: 1234567890,
                               user_id: 'XXXXXX')

OAuth 2.0 Authorization Flow

  • Create a client instance (ensure that redirect_uri is passed in):
client = 'XXXXXX',
                               client_secret: 'xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx',
                               redirect_uri: '')
  • Generate a link for your app's Fitbit authorization page:
# =>
  • Follow the generated link to Fitbit's authorization page. After granting permission for your app, you're sent to the redirect_uri, with an appended authorization code param, which you'll exchange for an access token:

You're now authorized and can make calls to Fitbit's API.

Interacting with the API

Once a valid token has been generated, you're able to make API calls via the client object:

# => { "foods" => [{ "isFavorite" => true, "logDate" => "2015-06-26", "logId" => 1820, "loggedFood" => { "accessLevel" => "PUBLIC", "amount" => 132.57, "brand" => "", "calories" => 752, ...}] }

To make responses more easily suited for attribute-assignment, they can be parsed to return a hash whose keys are in snake_case format. This can be done by setting the client's snake_case_keys option to true:

client.snake_case_keys = true
# => { "foods" => [{ "is_favorite" => true, "log_date" => "2015-06-26", "log_id" => 1820, "logged_food" => { "access_level" => "PUBLIC", "amount" => 132.57, "brand" => "", "calories" => 752, ...}] }

Similarly, all arguments passed in through a POST request are automatically converted to camelCase before they hit Fitbit's API, making it easy to keep your codebase stylistically consistent. For example, all of the following would result in valid API calls:

# options with snake_cased keys
client.log_activity activity_id: 12345, duration_millis: '50000'
# options with camelCased keys
client.log_activity activityId: 54321, durationMillis: '44100'
# options with mixed snake and camel cased keys
client.log_activity activity_id: 12345, durationMillis: '683300'


When initializing a FitbitAPI::Client instance, you're given access to a handful of options:

  • :api_version - API version to be used when making requests (default: "1")

  • :unit_system - The measurement unit system to use for response values (default: "en_US" | available: "en_US", "en_GB", and "any" for metric)

  • :locale - The locale to use for response values (default: "en_US" | available: "en_US", "fr_FR", "de_DE", "es_ES", "en_GB", "en_AU", "en_NZ" and "ja_JP")

  • :scope - A space-delimited list of the permissions you are requesting (default: "activity nutrition profile settings sleep social weight heartrate" | available: "activity", "heartrate", "location", "nutrition", "profile", "settings" "sleep", "social" and "weight")

  • :snake_case_keys - Transform returned object's keys to snake case format (default: false)

  • :symbolize_keys - Transform returned object's keys to symbols (default: false)

If using this library in Rails, you can configure your options using an initializer:

# config/initializers/fitbit_api.rb

FitbitAPI.configure do |config|
  config.client_id       = 'XXXX'
  config.client_secret   = 'xxxx'
  config.snake_case_keys = true
  config.symbolize_keys  = true


This gem is available as open source under the terms of the MIT License.