Ruby Server SDK

Setup the SDK

1. Install the SDK

   If you're using Bundler, add the gem to your Gemfile from command line:

   shell

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   bundle add statsig
   

   or directly include it in your Gemfile and run bundle install:

   shell

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   gem "statsig", ">= X.Y.Z"
   

   Check out the latest versions on https://rubygems.org/gems/statsig

2. Initialize the SDK

   After installation, initialize the SDK using a Server Secret Key from the Statsig console.

   Don't embed your Server Secret Key in client-side applications, or expose it in any external-facing documents. However, if you accidentally expose it, you can create a new one in the Statsig console.

   ruby

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   require 'statsig'
   
   Statsig.initialize('server-secret-key')
   

   ruby

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   # Or, if you want to initialize with certain options
   options = StatsigOptions.new({'tier' => 'staging'}, network_timeout: 5)
   
   # And a callback when the initialization network request fails
     def error_callback(e)
       puts e
     end
   
   
   ...
   Statsig.initialize('server-secret-key', options, method(:error_callback))
   

   Initializing Statsig in a Rails application

   If your application is using Rails, you should initialize Statsig in config/initializers/statsig.rb:

   ruby

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   Statsig.initialize('server-secret-key', options)
   

   Initializing Statsig when using Unicorn, Puma, Passenger, or Sidekiq

   For Unicorn, you should initialize Statsig within an after_fork hook in your unicorn.rb config file:

   ruby

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   after_fork do |server,worker|
     Statsig.initialize('server-secret-key', options)
   end
   

   For Puma, you should initialize Statsig within an on_worker_boot hook in your puma.rb config file:

   ruby

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   on_worker_boot do
     Statsig.initialize('server-secret-key', options)
   end
   

   For Passenger, you should initialize Statsig in your config.ru config file:

   ruby

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   if defined?(PhusionPassenger)
     PhusionPassenger.on_event(:starting_worker_process) do |forked|
       Statsig.initialize('server-secret-key', options)
     end
   end
   

   For Sidekiq, you should initialize Statsig in your sidekiq.rb/server configuration file:

   ruby

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   Sidekiq.configure_server do |config|
     config.on(:startup) do
       Statsig.initialize
     end
   
     config.on(:shutdown) do
       Statsig.shutdown
     end
   end
   

   If you're using Rails in combination with any of the above, initialize using the specific process lifecycle hooks exposed by the respective tool. You can initialize in multiple places to ensure the SDK is fully usable, including all background processing.

   initialize performs a network request. After initialize completes, virtually all SDK operations are synchronous (refer to Evaluating Feature Gates in the Statsig SDK). The SDK fetches updates from Statsig in the background, independently of API calls.

Working with the SDK

Checking a Feature Flag/Gate

After you initialize the SDK, you can check a Feature Gate. Feature Gates create logic branches in code that you can roll out to different users from the Statsig Console. Gates are always CLOSED or OFF (return false;) by default.

All APIs require you to specify the user (refer to Statsig user) associated with the request. For example, to check a gate for a user:

user = StatsigUser.new({'userID' => 'some_user_id'})
if Statsig.check_gate(user, 'use_new_feature')
  # Gate is on, enable new feature
else
  # Gate is off
end

Reading a Dynamic Config

Feature Gates work well for simple on/off switches with optional user targeting. To send a different set of values (strings, numbers, and so on) to clients based on specific user attributes such as country, use Dynamic Configs. The Dynamic Config API is similar to Feature Gates, but returns a full JSON object configured on the server, from which you can fetch typed parameters.

config = Statsig.get_config(user, 'awesome_product_details')

# The 2nd parameter is the default value to be used in case the given parameter name does not exist on
# the Dynamic Config object. This can happen when there is a typo, or when the user is offline and the
# value has not been cached on the client.
item_name = config.get('product_name', 'Awesome Product v1');
price = config.get('price', 10.0);
shouldDiscount = config.get('discount', false);

# Or just get the whole json object backing this config if you prefer
json = config.value

Getting a Layer/Experiment

Use Layers/Experiments to run A/B/n experiments. Two APIs are available, but Statsig recommends layers for faster iterations with parameter reuse.

# Values via getLayer

layer = Statsig.get_layer(user, "user_promo_experiments")
title = layer.get("title", "Welcome to Statsig!")
discount = layer.get("discount", 0.1)

# or, via getExperiment

title_exp = Statsig.get_experiment(user, "new_user_promo_title")
price_exp = Statsig.get_experiment(user, "new_user_promo_price")

title = title_exp.get("title", "Welcome to Statsig!")
discount = price_exp.get("discount", 0.1)

...

price = msrp * (1 - discount)

Logging an Event

To track custom events and measure how features or experiment groups affect those events, call the Log Event API. Specify the user and event name to log, and optionally provide a value and metadata object:

Statsig.log_event(
  user,
  'add_to_cart',
  'SKU_12345',
  {
    'price' => '9.99',
    'item_name' => 'diet_coke_48_pack'
  }
)

For more about identifying users, group analytics, and best practices, go to the logging events guide.

Statsig User

When calling APIs that require a user, pass as much information as possible. More user information enables advanced gate and config conditions (like country or OS/browser level checks), and lets Statsig accurately measure the impact of your experiments on your metrics and events. Statsig requires at least one identifier (userID or customID) to provide a consistent experience for a given user. Refer to userID requirements for more detail.

In addition to userID, the top-level fields on StatsigUser are email, ip, userAgent, country, locale, and appVersion. You can also pass any key-value pairs in an object/dictionary to the custom field to create targeting based on them.

Typing on the StatsigUser object is lenient: you can pass numbers, strings, arrays, objects, and even enums or classes. However, evaluation operators only work on primitive types, mostly strings and numbers. The SDK attempts to cast custom field types to match the operator, but Statsig doesn't guarantee evaluation results for other types. For example, the SDK compares an array set as a custom field only as a string: there's no operator to match a value within that array.

Private Attributes

To keep sensitive user PII data out of logs, use the privateAttributes field on the StatsigUser object. This field accepts an object/dictionary of private user attributes. The SDK uses any attribute set in privateAttributes only for evaluation/targeting and removes it from all logs before Statsig sends them to its servers.

For example, if a feature gate should only pass for users with emails ending in "@statsig.com", but you don't want to log email addresses to Statsig, add the key-value pair { email: "my_user@statsig.com" } to privateAttributes on the user.

Statsig Options

initialize() takes an optional options parameter in addition to the secret key to customize the Statsig client. Available options:

• environment: Hash, default nil
  • a Hash you can use to set environment variables that apply to all your users in the same session, for targeting purposes.
  • The most common usage is to set the "tier" (string), and have feature gates pass/fail for specific environments. The accepted values are "production", "staging" and "development", e.g. StatsigOptions.New({ 'tier' => 'staging' }).
• download_config_specs_url: String, default "https://api.statsigcdn.com/v2/download_config_specs/"
  • The url used specifically to call download_config_specs
• log_event_url: String, default "https://statsigapi.net/v1/log_event"
  • The url used specifically to call log_event
• get_id_lists_url: String, default "https://statsigapi.net/v1/get_id_lists"
  • The url used specifically to call get_id_lists
• rulesets_sync_interval: Number, default 10
  • The interval (in seconds) to poll for changes to your Statsig configuration
• idlists_sync_interval: Number, default 60
  • The interval (in seconds) to poll for changes to id lists
• disable_rulesets_sync: Boolean, default false
  • Disable background syncing for rulesets
• disable_idlists_sync: Boolean, default false
  • Disable background syncing for id lists
• logging_interval_seconds: Number, default 60
  • How often to flush logs to Statsig
• logging_max_buffer_size: Number, default 1000, you can set it lower but the server drops anything over 1000
  • The maximum number of events to batch before flushing logs to the server
• local_mode: Boolean, default false
  • Restricts the SDK to not issue any network requests and only respond with default values (or local overrides)
• bootstrap_values: String, default nil
  • A string that represents all rules for all feature gates, dynamic configs and experiments. Provide it to bootstrap the Statsig server SDK at initialization in case your server runs into network issue or Statsig server is down temporarily.
• rules_updated_callback: function, default nil
  • A callback function called whenever the rulesets update
• data_store: IDataStore, default nil
  • A class that extends IDataStore. Use it to provide values from a common data store (like Redis) to initialize the Statsig SDK.
• idlist_threadpool_size: Number, default 3
  • The number of threads allocated to syncing IDLists
• logger_threadpool_size: Number, default 3
  • The number of threads allocated to posting event logs
• disable_diagnostics_logging: Boolean, default false
  • Should diagnostics be logged. These include performance metrics for initialize
• disable_sorbet_logging_handlers: Boolean, default false
  • Statsig utilizes Sorbet (https://sorbet.org) to ensure type safety of the SDK. This includes logging to console when it detects errors. You can disable this logging by setting this flag to true.
• network_timeout: Number, default nil
  • Maximum number of seconds to wait for a network call before timing out
• post_logs_retry_limit: Number, default 3
  • Number of times to retry sending a batch of failed log events
• post_logs_retry_backoff: Number/Function, default nil
  • The number of seconds, or a function that returns the number of seconds based on the number of retries remaining which overrides the default backoff time between retries
• user_persistent_storage: IUserPersistentStorage, default nil
  • A storage adapter for persisted values. Use it for sticky bucketing users in experiments. Implements Statsig::Interfaces::IUserPersistentStorage.

Shutdown

To gracefully shutdown the SDK and flush all events:

Statsig.shutdown

Client SDK bootstrapping

The Statsig server SDK can generate the initialization values for a client SDK. This is useful for server-side rendering (SSR) or when you want to pre-fetch values for a client.

values = Statsig.get_client_initialize_response(user); # Hash[String, Any] | Nil

Local Overrides

You can override the values the SDK returns for testing purposes, which is useful for local development when testing specific scenarios.

# Adding gate overrides
Statsig.override_gate("a_gate_name", true)

# Adding config overrides
Statsig.override_config("a_config_name", {"key" => "value"})

Manual Exposures

Statsig SDKs automatically log an exposure event every time you check a gate/experiment/config. In some scenarios, you may want to control when to log an exposure.

Gates

result = Statsig.check_gate(user, 'a_gate_name', CheckGateOptions.new(disable_log_exposure: true))

Statsig.manually_log_gate_exposure(user, 'a_gate_name')

Configs

config = Statsig.get_config(user, 'a_dynamic_config_name', GetConfigOptions.new(disable_log_exposure: true))

Statsig.manually_log_config_exposure(user, 'a_dynamic_config_name')

Experiments

experiment = Statsig.get_experiment(user, 'an_experiment_name', GetExperimentOptions.new(disable_log_exposure: true))

Statsig.manually_log_experiment_exposure(user, 'an_experiment_name')

Layers

layer = Statsig.get_layer(user, 'a_layer_name', GetLayerOptions.new(disable_log_exposure: true))
paramValue = layer.get('a_param_name', 'fallback_value')

Statsig.manually_log_layer_parameter_exposure(user, 'a_layer_name', 'a_param_name')

User persistent storage

User Persistent Storage is a storage adapter for running sticky experiments that persists user assignments across sessions.

Interface

class IUserPersistentStorage
	def load(key)
		nil
	end

	def save(key, data) end
end

Example Implementation

class DummyPersistentStorageAdapter < Statsig::Interfaces::IUserPersistentStorage
  attr_accessor :store

  def initialize
    @store = {}
  end

  def load(key)
    return nil unless @store&.key?(key)

    @store[key]
  end

  def save(key, data)
    @store[key] = data
  end
end

Multi-instance usage

To create multiple independent instances of the Statsig SDK (for example, to use different API keys or configurations), use the instance-based approach:

sdk_instance = StatsigDriver.new(secret_key, options, error_callback)

FAQ

How do I run experiments for logged out users

Refer to the guide on device level experiments.

How can I mock or override the SDK for testing

Starting in v1.12.0+, the Ruby SDK supports localMode and overrides. Refer to Local Overrides.

• localMode is a boolean parameter in StatsigOptions when initializing the SDK. It restricts all network traffic, so the SDK operates offline and only returns default or override values.

Can I generate the initialize response for a client SDK using the Ruby server SDK

Yes. Refer to Client SDK Bootstrapping.

Reference

Type StatsigUser

export type StatsigUser = {
class StatsigUser
  attr_accessor :user_id
  attr_accessor :email
  attr_accessor :ip
  attr_accessor :user_agent
  attr_accessor :country
  attr_accessor :locale
  attr_accessor :app_version
  attr_accessor :statsig_environment
  attr_accessor :custom_ids # Hash of key:string value:string
  attr_accessor :private_attributes # Hash of key:string value:string
  
  @custom # Hash of key:string value:string
  
  def initialize(user_hash)
    @statsig_environment = Hash.new
    if user_hash.is_a?(Hash)
      @user_id = user_hash['userID'] || user_hash['user_id']
      @user_id = @user_id.to_s unless @user_id.nil?
      @email = user_hash['email']
      @ip = user_hash['ip']
      @user_agent = user_hash['userAgent'] || user_hash['user_agent']
      @country = user_hash['country']
      @locale = user_hash['locale']
      @app_version = user_hash['appVersion'] || user_hash['app_version']
      @custom = user_hash['custom'] if user_hash['custom'].is_a? Hash
      @statsig_environment = user_hash['statsigEnvironment']
      @private_attributes = user_hash['privateAttributes'] if user_hash['privateAttributes'].is_a? Hash
      custom_ids = user_hash['customIDs'] || user_hash['custom_ids']
      @custom_ids = custom_ids if custom_ids.is_a? Hash
    end
  end
end

Type StatsigOptions

class StatsigOptions
  attr_accessor :environment
  attr_accessor :download_config_specs_url
  attr_accessor :log_event_url
  attr_accessor :get_id_lists_url
  attr_accessor :rulesets_sync_interval
  attr_accessor :idlists_sync_interval
  attr_accessor :disable_rulesets_sync
  attr_accessor :disable_idlists_sync
  attr_accessor :logging_interval_seconds
  attr_accessor :logging_max_buffer_size
  attr_accessor :local_mode
  attr_accessor :bootstrap_values
  attr_accessor :rules_updated_callback
  attr_accessor :data_store
  attr_accessor :idlist_threadpool_size
  attr_accessor :logger_threadpool_size
  attr_accessor :disable_diagnostics_logging
  attr_accessor :disable_sorbet_logging_handlers
  attr_accessor :network_timeout
  attr_accessor :post_logs_retry_limit
  attr_accessor :post_logs_retry_backoff
  attr_accessor :user_persistent_storage

  def initialize(
    environment = nil,
    download_config_specs_url: nil,
    log_event_url: nil,
    get_id_lists_url: nil,
    rulesets_sync_interval: 10,
    idlists_sync_interval: 60,
    disable_rulesets_sync: false,
    disable_idlists_sync: false,
    logging_interval_seconds: 60,
    logging_max_buffer_size: 1000,
    local_mode: false,
    bootstrap_values: nil,
    rules_updated_callback: nil,
    data_store: nil,
    idlist_threadpool_size: 3,
    logger_threadpool_size: 3,
    disable_diagnostics_logging: false,
    disable_sorbet_logging_handlers: false,
    network_timeout: nil,
    post_logs_retry_limit: 3,
    post_logs_retry_backoff: nil,
    user_persistent_storage: nil
  )
  end
end

DataStore

module Statsig
  module Interfaces
    class IDataStore
      def init
      end

      def get(key)
        nil
      end

      def set(key, value)
      end

      def shutdown
      end
    end
  end
end