diff --git a/lib/checkout_sdk/environment_subdomain.rb b/lib/checkout_sdk/environment_subdomain.rb
index a65260a..d10d653 100644
--- a/lib/checkout_sdk/environment_subdomain.rb
+++ b/lib/checkout_sdk/environment_subdomain.rb
@@ -29,8 +29,7 @@ def add_subdomain_to_api_url_environment(environment, subdomain)
       api_url = environment.base_uri
       new_environment = api_url
 
-      # Regex to match a subdomain consisting of 8 to 11 lowercase alphanumeric characters
-      if subdomain =~ /^[0-9a-z]{8,11}$/
+      if subdomain =~ /^[0-9a-z]+$/
         url_parts = URI.parse(api_url)
         new_host = "#{subdomain}.#{url_parts.host}"
 
diff --git a/spec/checkout_sdk/configuration/configuration_spec.rb b/spec/checkout_sdk/configuration/configuration_spec.rb
index a97d596..3da329a 100644
--- a/spec/checkout_sdk/configuration/configuration_spec.rb
+++ b/spec/checkout_sdk/configuration/configuration_spec.rb
@@ -31,9 +31,10 @@ class FakeLogger
   end
 
   [
-    %w[123dmain https://123dmain.api.sandbox.checkout.com/],
-    %w[123domain https://123domain.api.sandbox.checkout.com/],
-    %w[1234domain https://1234domain.api.sandbox.checkout.com/],
+    %w[a https://a.api.sandbox.checkout.com/],
+    %w[ab https://ab.api.sandbox.checkout.com/],
+    %w[abc https://abc.api.sandbox.checkout.com/],
+    %w[abc1 https://abc1.api.sandbox.checkout.com/],
     %w[12345domain https://12345domain.api.sandbox.checkout.com/]
   ].each do |subdomain, expected_url|
     it "should create configuration with subdomain #{subdomain}" do
@@ -57,11 +58,13 @@ class FakeLogger
 
   [
     ['', 'https://api.sandbox.checkout.com/'],
-    %w[123 https://api.sandbox.checkout.com/],
-    %w[123bad https://api.sandbox.checkout.com/],
-    %w[12345domainBad https://api.sandbox.checkout.com/]
+    [' ', 'https://api.sandbox.checkout.com/'],
+    ['  ', 'https://api.sandbox.checkout.com/'],
+    [' - ', 'https://api.sandbox.checkout.com/'],
+    ['a b', 'https://api.sandbox.checkout.com/'],
+    ['ab bc1', 'https://api.sandbox.checkout.com/']
   ].each do |subdomain, expected_url|
-    it 'should create configuration with bad subdomain #{subdomain}' do
+    it "should create configuration with bad subdomain #{subdomain}" do
       environment_subdomain = CheckoutSdk::EnvironmentSubdomain.new(CheckoutSdk::Environment.sandbox, subdomain)
 
       configuration = CheckoutSdk::CheckoutConfiguration.new(