diff --git a/Gemfile.lock b/Gemfile.lock
index c4ac2b6..b844b11 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -1,7 +1,7 @@
 PATH
   remote: .
   specs:
-    absmartly-sdk (1.2.1)
+    absmartly-sdk (1.2.2)
       base64 (~> 0.2)
       faraday (~> 2.0)
       faraday-retry (~> 2.0)
diff --git a/lib/a_b_smartly.rb b/lib/a_b_smartly.rb
index 60474db..6328eda 100644
--- a/lib/a_b_smartly.rb
+++ b/lib/a_b_smartly.rb
@@ -1,51 +1,92 @@
 # frozen_string_literal: true
 
 require "time"
-require "singleton"
-require "forwardable"
 require_relative "context"
 require_relative "audience_matcher"
-require_relative "a_b_smartly_config"
-require_relative "absmartly/version"
+require_relative "default_context_data_provider"
+require_relative "default_context_event_handler"
+require_relative "default_variable_parser"
+require_relative "default_audience_deserializer"
+require_relative "scheduled_thread_pool_executor"
 
 class ABSmartly
-  extend Forwardable
+  attr_accessor :context_data_provider, :context_event_handler,
+                :variable_parser, :scheduler, :context_event_logger,
+                :audience_deserializer, :client
 
-  attr_reader :config
-
-  def_delegators :@config, :context_data_provider, :context_event_handler, :variable_parser, :context_event_logger,
-                 :audience_deserializer, :client
-
-  def_delegators :@config, :endpoint, :api_key, :application, :environment
+  def self.configure_client(&block)
+    @@init_http = block
+  end
 
   def self.create(config)
-    new(config)
+    ABSmartly.new(config)
   end
 
   def initialize(config)
-    config.validate!
+    @@init_http = nil
+    @context_data_provider = config.context_data_provider
+    @context_event_handler = config.context_event_handler
+    @context_event_logger = config.context_event_logger
+    @variable_parser = config.variable_parser
+    @audience_deserializer = config.audience_deserializer
+    @scheduler = config.scheduler
+
+    if @context_data_provider.nil? || @context_event_handler.nil?
+      @client = config.client
+      raise ArgumentError.new("Missing Client instance configuration") if @client.nil?
+
+      if @context_data_provider.nil?
+        @context_data_provider = DefaultContextDataProvider.new(@client)
+      end
+
+      if @context_event_handler.nil?
+        @context_event_handler = DefaultContextEventHandler.new(@client)
+      end
+    end
 
-    @config = config
+    if @variable_parser.nil?
+      @variable_parser = DefaultVariableParser.new
+    end
+
+    if @audience_deserializer.nil?
+      @audience_deserializer = DefaultAudienceDeserializer.new
+    end
+    if @scheduler.nil?
+      @scheduler = ScheduledThreadPoolExecutor.new(1)
+    end
   end
 
-  def create_context(context_config)
-    Context.create(get_utc_format, context_config, context_data,
-                   context_data_provider, context_event_handler, context_event_logger, variable_parser,
-                   AudienceMatcher.new(audience_deserializer))
+  def create_context(config)
+    validate_params(config)
+    Context.create(get_utc_format, config, @context_data_provider.context_data,
+                   @context_data_provider, @context_event_handler, @context_event_logger, @variable_parser,
+                   AudienceMatcher.new(@audience_deserializer))
   end
 
-  def create_context_with(context_config, data)
-    Context.create(get_utc_format, context_config, data,
-                   context_data_provider, context_event_handler, context_event_logger, variable_parser,
-                   AudienceMatcher.new(audience_deserializer))
+  def create_context_with(config, data)
+    Context.create(get_utc_format, config, data,
+                   @context_data_provider, @context_event_handler, @context_event_logger, @variable_parser,
+                   AudienceMatcher.new(@audience_deserializer))
   end
 
   def context_data
-    context_data_provider.context_data
+    @context_data_provider.context_data
   end
 
   private
     def get_utc_format
       Time.now.utc.iso8601(3)
     end
+
+    def validate_params(params)
+      params.units.each do |key, value|
+        unless value.is_a?(String) || value.is_a?(Numeric)
+          raise ArgumentError.new("Unit '#{key}' UID is of unsupported type '#{value.class}'. UID must be one of ['string', 'number']")
+        end
+
+        if value.to_s.size.zero?
+          raise ArgumentError.new("Unit '#{key}' UID length must be >= 1")
+        end
+      end
+    end
 end
diff --git a/lib/a_b_smartly_config.rb b/lib/a_b_smartly_config.rb
index 581659f..42a4034 100644
--- a/lib/a_b_smartly_config.rb
+++ b/lib/a_b_smartly_config.rb
@@ -1,65 +1,49 @@
 # frozen_string_literal: true
 
-require "forwardable"
-
-require_relative "client"
-require_relative "client_config"
-require_relative "default_context_data_provider"
-require_relative "default_context_event_handler"
-require_relative "default_variable_parser"
-require_relative "default_audience_deserializer"
-
 class ABSmartlyConfig
-  extend Forwardable
-
-  attr_accessor :scheduler
-
-  attr_writer :context_data_provider, :context_event_handler, :audience_deserializer, :variable_parser, :client
-
-  attr_reader :client_config, :context_event_logger
-
-  def_delegators :@client_config, :endpoint, :api_key, :application, :environment
-  def_delegators :@client_config, :connect_timeout, :connection_request_timeout, :retry_interval, :max_retries
-
+  attr_accessor :context_data_provider, :context_event_handler,
+                :variable_parser, :scheduler, :context_event_logger,
+                :client, :audience_deserializer
   def self.create
-    new
+    ABSmartlyConfig.new
   end
 
-  def initialize
-    @client_config = ClientConfig.new
+  def context_data_provider=(context_data_provider)
+    @context_data_provider = context_data_provider
+    self
   end
 
-  def validate!
-    raise ArgumentError.new("event logger not configured") if context_event_logger.nil?
-    raise ArgumentError.new("failed to initialize client") if client.nil?
-    raise ArgumentError.new("failed to initialize context_data_provider") if context_data_provider.nil?
+  def context_event_handler=(context_event_handler)
+    @context_event_handler = context_event_handler
+    self
   end
 
-  def context_event_logger=(context_event_logger)
-    if context_event_logger.is_a?(Proc)
-      @context_event_logger = ContextEventLoggerCallback.new(context_event_logger)
-    else
-      @context_event_logger = context_event_logger
-    end
+  def context_data_provide
+    @context_event_handler
   end
 
-  def variable_parser
-    @variable_parser ||= DefaultVariableParser.new
+  def variable_parser=(variable_parser)
+    @variable_parser = variable_parser
+    self
   end
 
-  def audience_deserializer
-    @audience_deserializer ||= DefaultAudienceDeserializer.new
+  def scheduler=(scheduler)
+    @scheduler = scheduler
+    self
   end
 
-  def context_data_provider
-    @context_data_provider ||= DefaultContextDataProvider.new(client)
+  def context_event_logger=(context_event_logger)
+    @context_event_logger = context_event_logger
+    self
   end
 
-  def context_event_handler
-    @context_event_handler ||= DefaultContextEventHandler.new(client)
+  def audience_deserializer=(audience_deserializer)
+    @audience_deserializer = audience_deserializer
+    self
   end
 
-  def client
-    @client ||= Client.new(client_config)
+  def client=(client)
+    @client = client
+    self
   end
 end
diff --git a/lib/absmartly.rb b/lib/absmartly.rb
index 1fe3680..c2febb2 100644
--- a/lib/absmartly.rb
+++ b/lib/absmartly.rb
@@ -8,16 +8,16 @@
 require_relative "context_config"
 
 module Absmartly
+  @@init_config = nil
+
   class Error < StandardError
   end
 
   class << self
-    MUTEX = Thread::Mutex.new
+    attr_accessor :endpoint, :api_key, :application, :environment
 
     def configure_client
-      yield sdk_config
-
-      sdk_config.validate!
+      yield self
     end
 
     def create
@@ -40,15 +40,24 @@ def context_data
       sdk.context_data
     end
 
-    private_constant :MUTEX
-
     private
+      def client_config
+        @client_config = ClientConfig.create
+        @client_config.endpoint = @endpoint
+        @client_config.api_key = @api_key
+        @client_config.application = @application
+        @client_config.environment = @environment
+        @client_config
+      end
+
       def sdk_config
-        MUTEX.synchronize { @sdk_config ||= ABSmartlyConfig.create }
+        @sdk_config = ABSmartlyConfig.create
+        @sdk_config.client = Client.create(client_config)
+        @sdk_config
       end
 
       def sdk
-        MUTEX.synchronize { @sdk ||= create }
+        @sdk ||= create
       end
   end
 end
diff --git a/lib/absmartly/version.rb b/lib/absmartly/version.rb
index d2c762f..56b13dc 100644
--- a/lib/absmartly/version.rb
+++ b/lib/absmartly/version.rb
@@ -1,5 +1,5 @@
 # frozen_string_literal: true
 
 module Absmartly
-  VERSION = "1.2.1"
+  VERSION = "1.2.2"
 end
diff --git a/lib/client.rb b/lib/client.rb
index 79723b1..ea6ed7c 100644
--- a/lib/client.rb
+++ b/lib/client.rb
@@ -1,49 +1,80 @@
 # frozen_string_literal: true
 
-require "forwardable"
 require_relative "default_http_client"
 require_relative "default_http_client_config"
 require_relative "default_context_data_deserializer"
 require_relative "default_context_event_serializer"
 
 class Client
-  extend Forwardable
+  attr_accessor :url, :query, :headers, :http_client, :executor, :deserializer, :serializer
+  attr_reader :data_future, :promise, :exception
 
-  attr_accessor :http_client
-  attr_reader :config, :data_future, :promise, :exception
-
-  def_delegators :@config, :url, :query, :headers, :deserializer, :serializer
-  def_delegator :@http_client, :close
-  def_delegator :@promise, :success?
-
-  def self.create(config = nil, http_client = nil)
-    new(config, http_client)
+  def self.create(config, http_client = nil)
+    Client.new(config, http_client || DefaultHttpClient.create(DefaultHttpClientConfig.create))
   end
 
   def initialize(config = nil, http_client = nil)
-    @config = config || ClientConfig.new
-    @config.validate!
+    endpoint = config.endpoint
+    raise ArgumentError.new("Missing Endpoint configuration") if endpoint.nil? || endpoint.empty?
+
+    api_key = config.api_key
+    raise ArgumentError.new("Missing APIKey configuration") if api_key.nil? || api_key.empty?
+
+    application = config.application
+    raise ArgumentError.new("Missing Application configuration") if application.nil? || application.empty?
+
+    environment = config.environment
+    raise ArgumentError.new("Missing Environment configuration") if environment.nil? || environment.empty?
+
+    @url = "#{endpoint}/context"
+    @http_client = http_client
+    @deserializer = config.context_data_deserializer
+    @serializer = config.context_event_serializer
+    @executor = config.executor
 
-    @http_client = http_client || DefaultHttpClient.create(@config.http_client_config)
+    @deserializer = DefaultContextDataDeserializer.new if @deserializer.nil?
+    @serializer = DefaultContextEventSerializer.new if @serializer.nil?
+
+    @headers = {
+      "Content-Type": "application/json",
+      "X-API-Key": api_key,
+      "X-Application": application,
+      "X-Environment": environment,
+      "X-Application-Version": "0",
+      "X-Agent": "absmartly-ruby-sdk"
+    }
+
+    @query = {
+      "application": application,
+      "environment": environment
+    }
   end
 
   def context_data
-    @promise = http_client.get(config.url, config.query, config.headers)
+    @promise = @http_client.get(@url, @query, @headers)
     unless @promise.success?
       @exception = Exception.new(@promise.body)
       return self
     end
 
     content = (@promise.body || {}).to_s
-    @data_future = deserializer.deserialize(content, 0, content.size)
+    @data_future = @deserializer.deserialize(content, 0, content.size)
     self
   end
 
   def publish(event)
-    content = serializer.serialize(event)
-    response = http_client.put(config.url, nil, config.headers, content)
+    content = @serializer.serialize(event)
+    response = @http_client.put(@url, nil, @headers, content)
     return Exception.new(response.body) unless response.success?
 
     response
   end
+
+  def close
+    @http_client.close
+  end
+
+  def success?
+    @promise.success?
+  end
 end
diff --git a/lib/client_config.rb b/lib/client_config.rb
index 0b6437c..7434da5 100644
--- a/lib/client_config.rb
+++ b/lib/client_config.rb
@@ -1,33 +1,21 @@
 # frozen_string_literal: true
 
-require "forwardable"
-require_relative "default_context_data_deserializer"
-require_relative "default_context_event_serializer"
-require_relative "default_http_client_config"
-
 class ClientConfig
-  extend Forwardable
-
-  attr_accessor :endpoint, :api_key, :environment, :application
-
-  attr_reader :http_client_config
-
-  attr_writer :context_data_deserializer, :context_event_serializer
-
-  def_delegators :@http_client_config, :connect_timeout, :connection_request_timeout, :retry_interval, :max_retries
+  attr_accessor :endpoint, :api_key, :environment, :application, :deserializer,
+                :serializer, :executor
 
-  def self.create(endpoint: nil, environment: nil, application: nil, api_key: nil)
-    new(endpoint: endpoint, environment: environment, application: application, api_key: api_key)
+  def self.create
+    ClientConfig.new
   end
 
   def self.create_from_properties(properties, prefix)
     properties = properties.transform_keys(&:to_sym)
-    create(
-      endpoint: properties["#{prefix}endpoint".to_sym],
-      environment: properties["#{prefix}environment".to_sym],
-      application: properties["#{prefix}application".to_sym],
-      api_key: properties["#{prefix}apikey".to_sym]
-    )
+    client_config = create
+    client_config.endpoint = properties["#{prefix}endpoint".to_sym]
+    client_config.environment = properties["#{prefix}environment".to_sym]
+    client_config.application = properties["#{prefix}application".to_sym]
+    client_config.api_key = properties["#{prefix}apikey".to_sym]
+    client_config
   end
 
   def initialize(endpoint: nil, environment: nil, application: nil, api_key: nil)
@@ -35,60 +23,21 @@ def initialize(endpoint: nil, environment: nil, application: nil, api_key: nil)
     @environment = environment
     @application = application
     @api_key = api_key
-
-    @http_client_config = DefaultHttpClientConfig.new
   end
 
   def context_data_deserializer
-    @context_data_deserializer ||= DefaultContextDataDeserializer.new
-  end
-
-  def context_event_serializer
-    @context_event_serializer ||= DefaultContextEventSerializer.new
-  end
-
-  def deserializer=(deserializer)
-    @context_data_deserializer = deserializer
-  end
-
-  def serializer=(serializer)
-    @context_event_serializer = serializer
-  end
-
-  def deserializer
-    context_data_deserializer
+    @deserializer
   end
 
-  def serializer
-    context_event_serializer
+  def context_data_deserializer=(deserializer)
+    @deserializer = deserializer
   end
 
-  def url
-    @url ||= "#{endpoint}/context"
-  end
-
-  def headers
-    @headers ||= {
-      "Content-Type": "application/json",
-      "X-API-Key": api_key,
-      "X-Application": application,
-      "X-Environment": environment,
-      "X-Application-Version": "0",
-      "X-Agent": "absmartly-ruby-sdk"
-    }
-  end
-
-  def query
-    @query ||= {
-      "application": application,
-      "environment": environment
-    }
+  def context_event_serializer
+    @serializer
   end
 
-  def validate!
-    raise ArgumentError.new("Missing Endpoint configuration") if endpoint.nil? || endpoint.empty?
-    raise ArgumentError.new("Missing APIKey configuration") if api_key.nil? || api_key.empty?
-    raise ArgumentError.new("Missing Application configuration") if application.nil? || application.empty?
-    raise ArgumentError.new("Missing Environment configuration") if environment.nil? || environment.empty?
+  def context_event_serializer=(serializer)
+    @serializer = serializer
   end
 end
diff --git a/lib/context.rb b/lib/context.rb
index 397abdb..964065d 100644
--- a/lib/context.rb
+++ b/lib/context.rb
@@ -10,7 +10,7 @@
 require_relative "json/goal_achievement"
 
 class Context
-  attr_reader :pending_count
+  attr_reader :data, :pending_count
 
   def self.create(clock, config, data_future, data_provider,
                   event_handler, event_logger, variable_parser, audience_matcher)
@@ -114,10 +114,6 @@ def custom_assignment(experiment_name)
   def set_unit(unit_type, uid)
     check_not_closed?
 
-    unless uid.is_a?(String) || uid.is_a?(Numeric)
-      raise IllegalStateException.new("Unit '#{unit_type}' UID is of unsupported type '#{uid.class}'. UID must be one of ['string', 'number']")
-    end
-
     previous = @units[unit_type.to_sym]
     if !previous.nil? && previous != uid
       raise IllegalStateException.new("Unit '#{unit_type}' already set.")
@@ -545,6 +541,7 @@ def assign_data(data)
                 @experimentCustomFieldValues[custom_field_value.name] = value
 
               end
+
             end
           end
 
diff --git a/lib/context_config.rb b/lib/context_config.rb
index 0cb7fe7..9c036c6 100644
--- a/lib/context_config.rb
+++ b/lib/context_config.rb
@@ -69,8 +69,11 @@ def custom_assignment(experiment_name)
     @custom_assignments[experiment_name.to_sym]
   end
 
+
   def set_event_logger(event_logger)
     @event_logger = event_logger
     self
   end
+
+  attr_reader :event_logger
 end
diff --git a/lib/default_http_client.rb b/lib/default_http_client.rb
index ca777a3..eea0895 100644
--- a/lib/default_http_client.rb
+++ b/lib/default_http_client.rb
@@ -1,7 +1,7 @@
 # frozen_string_literal: true
 
 require "faraday"
-require "faraday/retry"
+require 'faraday/retry'
 require "uri"
 require_relative "http_client"
 
diff --git a/spec/a_b_smartly_spec.rb b/spec/a_b_smartly_spec.rb
index 634001a..23a8ca9 100644
--- a/spec/a_b_smartly_spec.rb
+++ b/spec/a_b_smartly_spec.rb
@@ -17,7 +17,6 @@
   it ".create" do
     config = ABSmartlyConfig.create
     config.client = client
-    config.context_event_logger = ContextEventLogger.new
     absmartly = described_class.create(config)
     expect(absmartly).not_to be_nil
   end
@@ -26,7 +25,7 @@
     expect {
       config = ABSmartlyConfig.create
       ABSmartly.create(config)
-    }.to raise_error(ArgumentError, "event logger not configured")
+    }.to raise_error(ArgumentError, "Missing Client instance configuration")
   end
 
   it ".create_context" do
diff --git a/spec/context_spec.rb b/spec/context_spec.rb
index 268076c..c5a7d91 100644
--- a/spec/context_spec.rb
+++ b/spec/context_spec.rb
@@ -736,7 +736,7 @@ def faraday_response(content)
     expect(context.custom_field_value("exp_test_ab", "country")).to eq("US,PT,ES,DE,FR")
     expect(context.custom_field_type("exp_test_ab", "country")).to eq("string")
 
-    data = { "123":  1, "456": 0 }
+    data = {"123":  1, "456": 0}
     expect(context.custom_field_value("exp_test_ab", "overrides")).to eq(data)
     expect(context.custom_field_type("exp_test_ab", "overrides")).to eq("json")
 
@@ -757,6 +757,7 @@ def faraday_response(content)
 
     expect(context.custom_field_type("exp_test_no_custom_fields", "languages")).to be_nil
     expect(context.custom_field_value("exp_test_no_custom_fields", "languages")).to be_nil
+
   end
 
   it "peek_treatmentReturnsOverrideVariant" do
@@ -1148,7 +1149,7 @@ class MockContextEventLoggerProxy < ContextEventLogger
   def initialize
     @called = 0
     @events = []
-    @logger = Logger.new(IO::NULL)
+    @logger = Logger.new(STDOUT)
   end
 
   def handle_event(event, data)
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index 3b55452..4b08390 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -2,7 +2,6 @@
 
 require "absmartly"
 require "helpers"
-require "ostruct"
 
 RSpec.configure do |config|
   # Enable flags like --only-failures and --next-failure