diff --git a/lib/pact.rb b/lib/pact.rb
index 01756361..75159569 100644
--- a/lib/pact.rb
+++ b/lib/pact.rb
@@ -5,6 +5,11 @@
 
 require 'pact/railtie' if defined?(Rails::Railtie)
 
+# Load core_ext polyfills (blank?/present?, deep_dup) before Zeitwerk eager-loads
+# the rest of the gem. Each polyfill is skipped if already defined by active_support
+# or any other library loaded by the host application.
+require 'pact/support/core_ext'
+
 module Pact
   class Error < StandardError; end
 
@@ -41,6 +46,7 @@ def self.configuration
 loader.ignore("#{__dir__}/pact/version.rb")
 loader.ignore("#{__dir__}/pact/rspec.rb")
 loader.ignore("#{__dir__}/pact/rspec")
+loader.ignore("#{__dir__}/pact/support/core_ext.rb")
 loader.ignore("#{__dir__}/pact/railtie.rb") unless defined?(Rails::Railtie)
 
 loader.setup
diff --git a/lib/pact/rspec/support/webmock/webmock_helpers.rb b/lib/pact/rspec/support/webmock/webmock_helpers.rb
index 57526ddd..615c3733 100644
--- a/lib/pact/rspec/support/webmock/webmock_helpers.rb
+++ b/lib/pact/rspec/support/webmock/webmock_helpers.rb
@@ -2,7 +2,7 @@
 
 module WebmockHelpers
   def self.turned_off
-    yield unless defined?(::WebMock)
+    return yield unless defined?(::WebMock)
 
     allow_net_connect = WebMock::Config.instance.allow_net_connect
     allow_localhost = WebMock::Config.instance.allow_localhost
diff --git a/lib/pact/support/core_ext.rb b/lib/pact/support/core_ext.rb
new file mode 100644
index 00000000..5a83db3f
--- /dev/null
+++ b/lib/pact/support/core_ext.rb
@@ -0,0 +1,93 @@
+# frozen_string_literal: true
+
+# Minimal active_support polyfills for blank?/present? and deep_dup.
+# Each block is skipped entirely if the method is already defined
+# (e.g. active_support is loaded by the host application).
+
+unless Object.method_defined?(:blank?)
+  class NilClass
+    def blank? = true
+    def present? = false
+  end
+
+  class FalseClass
+    def blank? = true
+    def present? = false
+  end
+
+  class TrueClass
+    def blank? = false
+    def present? = true
+  end
+
+  class String
+    BLANK_RE = /\A[[:space:]]*\z/
+
+    def blank?
+      empty? || BLANK_RE.match?(self)
+    end
+
+    def present? = !blank?
+  end
+
+  class Symbol
+    alias_method :blank?, :empty?
+    def present? = !blank?
+  end
+
+  class Array
+    alias_method :blank?, :empty?
+    def present? = !empty?
+  end
+
+  class Hash
+    alias_method :blank?, :empty?
+    def present? = !empty?
+  end
+
+  class Object
+    def blank? = respond_to?(:empty?) ? !!empty? : false
+    def present? = !blank?
+
+    def presence
+      self if present?
+    end
+  end
+end
+
+unless Object.method_defined?(:deep_dup)
+  class Object
+    def deep_dup
+      dup
+    rescue TypeError
+      self
+    end
+  end
+
+  class Array
+    def deep_dup
+      map(&:deep_dup)
+    end
+  end
+
+  class Hash
+    def deep_dup
+      hash = dup
+      each_pair do |key, value|
+        if ::String === key || ::Symbol === key
+          hash[key] = value.deep_dup
+        else
+          hash.delete(key)
+          hash[key.deep_dup] = value.deep_dup
+        end
+      end
+      hash
+    end
+  end
+
+  class Module
+    def deep_dup
+      name.nil? ? super : self
+    end
+  end
+end
diff --git a/pact.gemspec b/pact.gemspec
index d9a139ac..b43acdfb 100644
--- a/pact.gemspec
+++ b/pact.gemspec
@@ -27,6 +27,12 @@ Gem::Specification.new do |gem|
     'documentation_uri' => 'https://github.com/pact-foundation/pact-ruby/blob/master/README.md'
   }
 
+  # Optional runtime dependencies (not required by pact itself):
+  #   active_support — if already loaded, its blank?/present? take precedence over
+  #                    pact's built-in polyfill (lib/pact/support/blank.rb).
+  #   webmock        — only needed for WebMock integration via WebmockHelpers.
+  #                    Require it yourself before using that helper.
+
   # Core dependencies (code loading)
   gem.add_dependency 'zeitwerk', '~> 2.3'
   # For Pact support via Pact Rust Core