diff --git a/lib/momoapi-ruby/cli.rb b/lib/momoapi-ruby/cli.rb
index 0d58696..5b31b1f 100644
--- a/lib/momoapi-ruby/cli.rb
+++ b/lib/momoapi-ruby/cli.rb
@@ -1,13 +1,17 @@
 # frozen_string_literal: true
 
-require 'momoapi-ruby'
 require 'faraday'
 require 'json'
+require 'securerandom'
+
+require 'momoapi-ruby/config'
+require 'momoapi-ruby/errors'
+require 'momoapi-ruby'
 
 module Momoapi
   class CLI
     def initialize(option)
-      @uuid = Faraday.get('https://www.uuidgenerator.net/api/version4').body.chomp
+      @uuid = SecureRandom.uuid
       @host = option[:host]
       @key = option[:key]
       create_sandbox_user
@@ -22,27 +26,27 @@ def create_sandbox_user
         req.headers['Ocp-Apim-Subscription-Key'] = @key
         req.body = body.to_json
       end
-      if response.status == 201
-        generate_api_key
-      else
-        # TO DO: Add error handling here
-        puts response.body
+
+      unless response.status == 201
+        raise Error::APIError.new(response.body, response.status)
       end
+
+      generate_api_key
     end
 
     def generate_api_key
       @url = 'https://sandbox.momodeveloper.mtn.com/v1_0/apiuser/' +
              @uuid + '/apikey'
-      puts @url
       response = Faraday.post(@url) do |req|
         req.headers['Ocp-Apim-Subscription-Key'] = @key
       end
-      if response.status == 201
-        puts " User ID: #{@uuid} \n API key: #{response.body}"
-      else
-        # TO DO: Add error handling here
-        puts 'Error creating API key'
+
+      unless response.status == 201
+        raise Error::APIError.new(response.body, response.status)
       end
+
+      key = JSON.parse(response.body)
+      puts "\n User ID: #{@uuid} \n API key: #{key['apiKey']} \n\n"
     end
   end
 end
diff --git a/lib/momoapi-ruby/client.rb b/lib/momoapi-ruby/client.rb
index a938433..9b7df84 100644
--- a/lib/momoapi-ruby/client.rb
+++ b/lib/momoapi-ruby/client.rb
@@ -24,18 +24,18 @@ def send_request(method, path, headers, *_body)
 
     def interpret_response(resp)
       response = {
-        body: JSON.parse(resp.body),
+        body: resp.body,
         code: resp.status
       }
-      # unless 200 <= resp.status && resp.status < 300
-      #   handle_error(response[:code], response[:body])
-      # end
+      unless resp.status >= 200 && resp.status < 300
+        handle_error(response[:body], response[:status])
+      end
       response
     end
 
-    # def handle_error(response_code, response_body)
-    #   raise APIError(response_code, response_body)
-    # end
+    def handle_error(response_body, response_code)
+      raise Error::APIError.new(response_body, response_code)
+    end
 
     def get_auth_token(path, subscription_key)
       headers = {
@@ -53,7 +53,7 @@ def get_auth_token(path, subscription_key)
 
     def get_balance(path, subscription_key)
       headers = {
-        "X-Target-Environment": 'sandbox',
+        "X-Target-Environment": Momoapi.config.environment || 'sandbox',
         "Content-Type": 'application/json',
         "Ocp-Apim-Subscription-Key": subscription_key
       }
@@ -62,7 +62,7 @@ def get_balance(path, subscription_key)
 
     def get_transaction_status(path, subscription_key)
       headers = {
-        "X-Target-Environment": 'sandbox',
+        "X-Target-Environment": Momoapi.config.environment || 'sandbox',
         "Content-Type": 'application/json',
         "Ocp-Apim-Subscription-Key": subscription_key
       }
diff --git a/lib/momoapi-ruby/collection.rb b/lib/momoapi-ruby/collection.rb
index 235e7f9..b0e2ef2 100644
--- a/lib/momoapi-ruby/collection.rb
+++ b/lib/momoapi-ruby/collection.rb
@@ -1,5 +1,7 @@
 # frozen_string_literal: true
 
+require 'securerandom'
+
 require 'momoapi-ruby/config'
 require 'momoapi-ruby/client'
 
@@ -22,9 +24,9 @@ def get_transaction_status(transaction_id)
 
     def request_to_pay(phone_number, amount, external_id,
                        payee_note = '', payer_message = '', currency = 'EUR')
-      uuid = Faraday.get('https://www.uuidgenerator.net/api/version4').body.chomp
+      uuid = SecureRandom.uuid
       headers = {
-        "X-Target-Environment": 'sandbox',
+        "X-Target-Environment": Momoapi.config.environment || 'sandbox',
         "Content-Type": 'application/json',
         "X-Reference-Id": uuid,
         "Ocp-Apim-Subscription-Key": Momoapi.config.collection_primary_key
@@ -42,6 +44,7 @@ def request_to_pay(phone_number, amount, external_id,
       }
       path = '/collection/v1_0/requesttopay'
       send_request('post', path, headers, body)
+      uuid
     end
   end
 end
diff --git a/lib/momoapi-ruby/errors.rb b/lib/momoapi-ruby/errors.rb
index 9922db4..15f7c87 100644
--- a/lib/momoapi-ruby/errors.rb
+++ b/lib/momoapi-ruby/errors.rb
@@ -1,4 +1,10 @@
 # frozen_string_literal: true
 
-class APIError < StandardError
+module Error
+  class APIError < StandardError
+    def initialize(message, code)
+      @code = code
+      super(message)
+    end
+  end
 end