diff --git a/README.md b/README.md
index 114cb7b4..0190d834 100644
--- a/README.md
+++ b/README.md
@@ -88,9 +88,50 @@ SecureHeaders::Configuration.default do |config|
     img_src: %w(somewhereelse.com),
     report_uri: %w(https://report-uri.io/example-csp-report-only)
   })
+
+  # Optional: Use the modern report-to directive (with Reporting-Endpoints header)
+  config.csp = config.csp.merge({
+    report_to: "csp-endpoint"
+  })
+
+  # When using report-to, configure the reporting endpoints header
+  config.reporting_endpoints = {
+    "csp-endpoint": "https://report-uri.io/example-csp",
+    "csp-report-only": "https://report-uri.io/example-csp-report-only"
+  }
 end
 ```
 
+### CSP Reporting
+
+SecureHeaders supports both the legacy `report-uri` and the modern `report-to` directives for CSP violation reporting:
+
+#### report-uri (Legacy)
+The `report-uri` directive sends violations to a URL endpoint. It's widely supported but limited to POST requests with JSON payloads.
+
+```ruby
+config.csp = {
+  default_src: %w('self'),
+  report_uri: %w(https://example.com/csp-report)
+}
+```
+
+#### report-to (Modern)
+The `report-to` directive specifies a named reporting endpoint defined in the `Reporting-Endpoints` header. This enables more flexible reporting through the HTTP Reporting API standard.
+
+```ruby
+config.csp = {
+  default_src: %w('self'),
+  report_to: "csp-endpoint"
+}
+
+config.reporting_endpoints = {
+  "csp-endpoint": "https://example.com/reports"
+}
+```
+
+**Recommendation:** Use both `report-uri` and `report-to` for maximum compatibility while transitioning to the modern approach.
+
 ### Deprecated Configuration Values
 * `block_all_mixed_content` - this value is deprecated in favor of `upgrade_insecure_requests`. See https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/block-all-mixed-content for more information.
 
diff --git a/lib/secure_headers.rb b/lib/secure_headers.rb
index 6426e538..42d30779 100644
--- a/lib/secure_headers.rb
+++ b/lib/secure_headers.rb
@@ -11,6 +11,7 @@
 require "secure_headers/headers/referrer_policy"
 require "secure_headers/headers/clear_site_data"
 require "secure_headers/headers/expect_certificate_transparency"
+require "secure_headers/headers/reporting_endpoints"
 require "secure_headers/middleware"
 require "secure_headers/railtie"
 require "secure_headers/view_helper"
@@ -208,7 +209,7 @@ def raise_on_unknown_target(target)
 
     def config_and_target(request, target)
       config = config_for(request)
-      target = guess_target(config) unless target
+      target ||= guess_target(config)
       raise_on_unknown_target(target)
       [config, target]
     end
diff --git a/lib/secure_headers/configuration.rb b/lib/secure_headers/configuration.rb
index e96f4f9d..1c83263a 100644
--- a/lib/secure_headers/configuration.rb
+++ b/lib/secure_headers/configuration.rb
@@ -131,6 +131,7 @@ def deep_copy_if_hash(value)
       csp: ContentSecurityPolicy,
       csp_report_only: ContentSecurityPolicy,
       cookies: Cookie,
+      reporting_endpoints: ReportingEndpoints,
     }.freeze
 
     CONFIG_ATTRIBUTES = CONFIG_ATTRIBUTES_TO_HEADER_CLASSES.keys.freeze
@@ -167,6 +168,7 @@ def initialize(&block)
       @x_permitted_cross_domain_policies = nil
       @x_xss_protection = nil
       @expect_certificate_transparency = nil
+      @reporting_endpoints = nil
 
       self.referrer_policy = OPT_OUT
       self.csp = ContentSecurityPolicyConfig.new(ContentSecurityPolicyConfig::DEFAULT)
@@ -192,6 +194,7 @@ def dup
       copy.clear_site_data = @clear_site_data
       copy.expect_certificate_transparency = @expect_certificate_transparency
       copy.referrer_policy = @referrer_policy
+      copy.reporting_endpoints = self.class.send(:deep_copy_if_hash, @reporting_endpoints)
       copy
     end
 
diff --git a/lib/secure_headers/headers/clear_site_data.rb b/lib/secure_headers/headers/clear_site_data.rb
index 0fdc0c2a..05d26a8f 100644
--- a/lib/secure_headers/headers/clear_site_data.rb
+++ b/lib/secure_headers/headers/clear_site_data.rb
@@ -11,43 +11,41 @@ class ClearSiteData
     EXECUTION_CONTEXTS = "executionContexts".freeze
     ALL_TYPES = [CACHE, COOKIES, STORAGE, EXECUTION_CONTEXTS]
 
-    class << self
-      # Public: make an clear-site-data header name, value pair
-      #
-      # Returns nil if not configured, returns header name and value if configured.
-      def make_header(config = nil, user_agent = nil)
-        case config
-        when nil, OPT_OUT, []
-          # noop
-        when Array
-          [HEADER_NAME, make_header_value(config)]
-        when true
-          [HEADER_NAME, make_header_value(ALL_TYPES)]
-        end
+    # Public: make an clear-site-data header name, value pair
+    #
+    # Returns nil if not configured, returns header name and value if configured.
+    def self.make_header(config = nil, user_agent = nil)
+      case config
+      when nil, OPT_OUT, []
+        # noop
+      when Array
+        [HEADER_NAME, make_header_value(config)]
+      when true
+        [HEADER_NAME, make_header_value(ALL_TYPES)]
       end
+    end
 
-      def validate_config!(config)
-        case config
-        when nil, OPT_OUT, true
-          # valid
-        when Array
-          unless config.all? { |t| t.is_a?(String) }
-            raise ClearSiteDataConfigError.new("types must be Strings")
-          end
-        else
-          raise ClearSiteDataConfigError.new("config must be an Array of Strings or `true`")
+    def self.validate_config!(config)
+      case config
+      when nil, OPT_OUT, true
+        # valid
+      when Array
+        unless config.all? { |t| t.is_a?(String) }
+          raise ClearSiteDataConfigError.new("types must be Strings")
         end
+      else
+        raise ClearSiteDataConfigError.new("config must be an Array of Strings or `true`")
       end
+    end
 
-      # Public: Transform a clear-site-data config (an Array of Strings) into a
-      # String that can be used as the value for the clear-site-data header.
-      #
-      # types - An Array of String of types of data to clear.
-      #
-      # Returns a String of quoted values that are comma separated.
-      def make_header_value(types)
-        types.map { |t| %("#{t}") }.join(", ")
-      end
+    # Public: Transform a clear-site-data config (an Array of Strings) into a
+    # String that can be used as the value for the clear-site-data header.
+    #
+    # types - An Array of String of types of data to clear.
+    #
+    # Returns a String of quoted values that are comma separated.
+    def self.make_header_value(types)
+      types.map { |t| %("#{t}") }.join(", ")
     end
   end
 end
diff --git a/lib/secure_headers/headers/content_security_policy.rb b/lib/secure_headers/headers/content_security_policy.rb
index ae225e7c..9d4a0242 100644
--- a/lib/secure_headers/headers/content_security_policy.rb
+++ b/lib/secure_headers/headers/content_security_policy.rb
@@ -63,6 +63,8 @@ def build_value
           build_sandbox_list_directive(directive_name)
         when :media_type_list
           build_media_type_list_directive(directive_name)
+        when :report_to_endpoint
+          build_report_to_directive(directive_name)
         end
       end.compact.join("; ")
     end
@@ -100,6 +102,13 @@ def build_media_type_list_directive(directive)
       end
     end
 
+    def build_report_to_directive(directive)
+      return unless endpoint_name = @config.directive_value(directive)
+      if endpoint_name && endpoint_name.is_a?(String) && !endpoint_name.empty?
+        [symbol_to_hyphen_case(directive), endpoint_name].join(" ")
+      end
+    end
+
     # Private: builds a string that represents one directive in a minified form.
     #
     # directive_name - a symbol representing the various ALL_DIRECTIVES
@@ -179,11 +188,12 @@ def append_nonce(source_list, nonce)
     end
 
     # Private: return the list of directives,
-    # starting with default-src and ending with report-uri.
+    # starting with default-src and ending with reporting directives (alphabetically ordered).
     def directives
       [
         DEFAULT_SRC,
         BODY_DIRECTIVES,
+        REPORT_TO,
         REPORT_URI,
       ].flatten
     end
diff --git a/lib/secure_headers/headers/cookie.rb b/lib/secure_headers/headers/cookie.rb
index 9d3f7cd1..8f78612c 100644
--- a/lib/secure_headers/headers/cookie.rb
+++ b/lib/secure_headers/headers/cookie.rb
@@ -7,10 +7,8 @@ module SecureHeaders
   class CookiesConfigError < StandardError; end
   class Cookie
 
-    class << self
-      def validate_config!(config)
-        CookiesConfig.new(config).validate!
-      end
+    def self.validate_config!(config)
+      CookiesConfig.new(config).validate!
     end
 
     attr_reader :raw_cookie, :config
diff --git a/lib/secure_headers/headers/expect_certificate_transparency.rb b/lib/secure_headers/headers/expect_certificate_transparency.rb
index 4b7272dd..582e8a05 100644
--- a/lib/secure_headers/headers/expect_certificate_transparency.rb
+++ b/lib/secure_headers/headers/expect_certificate_transparency.rb
@@ -9,31 +9,29 @@ class ExpectCertificateTransparency
     REQUIRED_MAX_AGE_ERROR      = "max-age is a required directive.".freeze
     INVALID_MAX_AGE_ERROR       = "max-age must be a number.".freeze
 
-    class << self
-      # Public: Generate a expect-ct header.
-      #
-      # Returns nil if not configured, returns header name and value if
-      # configured.
-      def make_header(config, use_agent = nil)
-        return if config.nil? || config == OPT_OUT
+    # Public: Generate a expect-ct header.
+    #
+    # Returns nil if not configured, returns header name and value if
+    # configured.
+    def self.make_header(config, use_agent = nil)
+      return if config.nil? || config == OPT_OUT
 
-        header = new(config)
-        [HEADER_NAME, header.value]
-      end
+      header = new(config)
+      [HEADER_NAME, header.value]
+    end
 
-      def validate_config!(config)
-        return if config.nil? || config == OPT_OUT
-        raise ExpectCertificateTransparencyConfigError.new(INVALID_CONFIGURATION_ERROR) unless config.is_a? Hash
+    def self.validate_config!(config)
+      return if config.nil? || config == OPT_OUT
+      raise ExpectCertificateTransparencyConfigError.new(INVALID_CONFIGURATION_ERROR) unless config.is_a? Hash
 
-        unless [true, false, nil].include?(config[:enforce])
-          raise ExpectCertificateTransparencyConfigError.new(INVALID_ENFORCE_VALUE_ERROR)
-        end
+      unless [true, false, nil].include?(config[:enforce])
+        raise ExpectCertificateTransparencyConfigError.new(INVALID_ENFORCE_VALUE_ERROR)
+      end
 
-        if !config[:max_age]
-          raise ExpectCertificateTransparencyConfigError.new(REQUIRED_MAX_AGE_ERROR)
-        elsif config[:max_age].to_s !~ /\A\d+\z/
-          raise ExpectCertificateTransparencyConfigError.new(INVALID_MAX_AGE_ERROR)
-        end
+      if !config[:max_age]
+        raise ExpectCertificateTransparencyConfigError.new(REQUIRED_MAX_AGE_ERROR)
+      elsif config[:max_age].to_s !~ /\A\d+\z/
+        raise ExpectCertificateTransparencyConfigError.new(INVALID_MAX_AGE_ERROR)
       end
     end
 
diff --git a/lib/secure_headers/headers/policy_management.rb b/lib/secure_headers/headers/policy_management.rb
index 3129c0d3..48fe1bdf 100644
--- a/lib/secure_headers/headers/policy_management.rb
+++ b/lib/secure_headers/headers/policy_management.rb
@@ -39,6 +39,7 @@ def self.included(base)
     SCRIPT_SRC = :script_src
     STYLE_SRC = :style_src
     REPORT_URI = :report_uri
+    REPORT_TO = :report_to
 
     DIRECTIVES_1_0 = [
       DEFAULT_SRC,
@@ -51,7 +52,8 @@ def self.included(base)
       SANDBOX,
       SCRIPT_SRC,
       STYLE_SRC,
-      REPORT_URI
+      REPORT_URI,
+      REPORT_TO
     ].freeze
 
     BASE_URI = :base_uri
@@ -110,9 +112,9 @@ def self.included(base)
 
     ALL_DIRECTIVES = (DIRECTIVES_1_0 + DIRECTIVES_2_0 + DIRECTIVES_3_0 + DIRECTIVES_EXPERIMENTAL).uniq.sort
 
-    # Think of default-src and report-uri as the beginning and end respectively,
+    # Think of default-src and report-uri/report-to as the beginning and end respectively,
     # everything else is in between.
-    BODY_DIRECTIVES = ALL_DIRECTIVES - [DEFAULT_SRC, REPORT_URI]
+    BODY_DIRECTIVES = ALL_DIRECTIVES - [DEFAULT_SRC, REPORT_URI, REPORT_TO]
 
     DIRECTIVE_VALUE_TYPES = {
       BASE_URI                  => :source_list,
@@ -129,10 +131,11 @@ def self.included(base)
       NAVIGATE_TO               => :source_list,
       OBJECT_SRC                => :source_list,
       PLUGIN_TYPES              => :media_type_list,
+      PREFETCH_SRC              => :source_list,
+      REPORT_TO                 => :report_to_endpoint,
+      REPORT_URI                => :source_list,
       REQUIRE_SRI_FOR           => :require_sri_for_list,
       REQUIRE_TRUSTED_TYPES_FOR => :require_trusted_types_for_list,
-      REPORT_URI                => :source_list,
-      PREFETCH_SRC              => :source_list,
       SANDBOX                   => :sandbox_list,
       SCRIPT_SRC                => :source_list,
       SCRIPT_SRC_ELEM           => :source_list,
@@ -158,6 +161,7 @@ def self.included(base)
       FORM_ACTION,
       FRAME_ANCESTORS,
       NAVIGATE_TO,
+      REPORT_TO,
       REPORT_URI,
     ]
 
@@ -344,6 +348,8 @@ def validate_directive!(directive, value)
           validate_require_sri_source_expression!(directive, value)
         when :require_trusted_types_for_list
           validate_require_trusted_types_for_source_expression!(directive, value)
+        when :report_to_endpoint
+          validate_report_to_endpoint_expression!(directive, value)
         else
           raise ContentSecurityPolicyConfigError.new("Unknown directive #{directive}")
         end
@@ -398,6 +404,18 @@ def validate_require_trusted_types_for_source_expression!(directive, require_tru
         end
       end
 
+      # Private: validates that a report-to endpoint expression:
+      # 1. is a string
+      # 2. is not empty
+      def validate_report_to_endpoint_expression!(directive, endpoint_name)
+        unless endpoint_name.is_a?(String)
+          raise ContentSecurityPolicyConfigError.new("#{directive} must be a string. Found #{endpoint_name.class} value")
+        end
+        if endpoint_name.empty?
+          raise ContentSecurityPolicyConfigError.new("#{directive} must not be empty")
+        end
+      end
+
       # Private: validates that a source expression:
       # 1. is an array of strings
       # 2. does not contain any deprecated, now invalid values (inline, eval, self, none)
diff --git a/lib/secure_headers/headers/referrer_policy.rb b/lib/secure_headers/headers/referrer_policy.rb
index a4589117..2094656c 100644
--- a/lib/secure_headers/headers/referrer_policy.rb
+++ b/lib/secure_headers/headers/referrer_policy.rb
@@ -15,29 +15,27 @@ class ReferrerPolicy
       unsafe-url
     )
 
-    class << self
-      # Public: generate an Referrer Policy header.
-      #
-      # Returns a default header if no configuration is provided, or a
-      # header name and value based on the config.
-      def make_header(config = nil, user_agent = nil)
-        return if config == OPT_OUT
-        config ||= DEFAULT_VALUE
-        [HEADER_NAME, Array(config).join(", ")]
-      end
+    # Public: generate an Referrer Policy header.
+    #
+    # Returns a default header if no configuration is provided, or a
+    # header name and value based on the config.
+    def self.make_header(config = nil, user_agent = nil)
+      return if config == OPT_OUT
+      config ||= DEFAULT_VALUE
+      [HEADER_NAME, Array(config).join(", ")]
+    end
 
-      def validate_config!(config)
-        case config
-        when nil, OPT_OUT
-          # valid
-        when String, Array
-          config = Array(config)
-          unless config.all? { |t| t.is_a?(String) && VALID_POLICIES.include?(t.downcase) }
-            raise ReferrerPolicyConfigError.new("Value can only be one or more of #{VALID_POLICIES.join(", ")}")
-          end
-        else
-          raise TypeError.new("Must be a string or array of strings. Found #{config.class}: #{config}")
+    def self.validate_config!(config)
+      case config
+      when nil, OPT_OUT
+        # valid
+      when String, Array
+        config = Array(config)
+        unless config.all? { |t| t.is_a?(String) && VALID_POLICIES.include?(t.downcase) }
+          raise ReferrerPolicyConfigError.new("Value can only be one or more of #{VALID_POLICIES.join(", ")}")
         end
+      else
+        raise TypeError.new("Must be a string or array of strings. Found #{config.class}: #{config}")
       end
     end
   end
diff --git a/lib/secure_headers/headers/reporting_endpoints.rb b/lib/secure_headers/headers/reporting_endpoints.rb
new file mode 100644
index 00000000..c5b048ff
--- /dev/null
+++ b/lib/secure_headers/headers/reporting_endpoints.rb
@@ -0,0 +1,51 @@
+# frozen_string_literal: true
+module SecureHeaders
+  class ReportingEndpointsConfigError < StandardError; end
+  class ReportingEndpoints
+    HEADER_NAME = "reporting-endpoints".freeze
+
+    class << self
+      # Public: generate a Reporting-Endpoints header.
+      #
+      # The config should be a Hash of endpoint names to URLs.
+      # Example: { "csp-endpoint" => "https://example.com/reports" }
+      #
+      # Returns nil if config is OPT_OUT or nil, or a header name and
+      # formatted header value based on the config.
+      def make_header(config = nil)
+        return if config.nil? || config == OPT_OUT
+        validate_config!(config)
+        [HEADER_NAME, format_endpoints(config)]
+      end
+
+      def validate_config!(config)
+        case config
+        when nil, OPT_OUT
+          # valid
+        when Hash
+          config.each_pair do |name, url|
+            unless name.is_a?(String) && !name.empty?
+              raise ReportingEndpointsConfigError.new("Endpoint name must be a non-empty string, got: #{name.inspect}")
+            end
+            unless url.is_a?(String) && !url.empty?
+              raise ReportingEndpointsConfigError.new("Endpoint URL must be a non-empty string, got: #{url.inspect}")
+            end
+            unless url.start_with?("https://")
+              raise ReportingEndpointsConfigError.new("Endpoint URLs must use https, got: #{url.inspect}")
+            end
+          end
+        else
+          raise TypeError.new("Must be a Hash of endpoint names to URLs. Found #{config.class}: #{config}")
+        end
+      end
+
+      private
+
+      def format_endpoints(config)
+        config.map do |name, url|
+          %{#{name}="#{url}"}
+        end.join(", ")
+      end
+    end
+  end
+end
diff --git a/lib/secure_headers/headers/strict_transport_security.rb b/lib/secure_headers/headers/strict_transport_security.rb
index 3d78a484..eaf46cb6 100644
--- a/lib/secure_headers/headers/strict_transport_security.rb
+++ b/lib/secure_headers/headers/strict_transport_security.rb
@@ -9,21 +9,19 @@ class StrictTransportSecurity
     VALID_STS_HEADER = /\Amax-age=\d+(; includeSubdomains)?(; preload)?\z/i
     MESSAGE = "The config value supplied for the HSTS header was invalid. Must match #{VALID_STS_HEADER}"
 
-    class << self
-      # Public: generate an hsts header name, value pair.
-      #
-      # Returns a default header if no configuration is provided, or a
-      # header name and value based on the config.
-      def make_header(config = nil, user_agent = nil)
-        return if config == OPT_OUT
-        [HEADER_NAME, config || DEFAULT_VALUE]
-      end
+    # Public: generate an hsts header name, value pair.
+    #
+    # Returns a default header if no configuration is provided, or a
+    # header name and value based on the config.
+    def self.make_header(config = nil, user_agent = nil)
+      return if config == OPT_OUT
+      [HEADER_NAME, config || DEFAULT_VALUE]
+    end
 
-      def validate_config!(config)
-        return if config.nil? || config == OPT_OUT
-        raise TypeError.new("Must be a string. Found #{config.class}: #{config} #{config.class}") unless config.is_a?(String)
-        raise STSConfigError.new(MESSAGE) unless config =~ VALID_STS_HEADER
-      end
+    def self.validate_config!(config)
+      return if config.nil? || config == OPT_OUT
+      raise TypeError.new("Must be a string. Found #{config.class}: #{config} #{config.class}") unless config.is_a?(String)
+      raise STSConfigError.new(MESSAGE) unless config =~ VALID_STS_HEADER
     end
   end
 end
diff --git a/lib/secure_headers/headers/x_content_type_options.rb b/lib/secure_headers/headers/x_content_type_options.rb
index 96f8d314..773bad82 100644
--- a/lib/secure_headers/headers/x_content_type_options.rb
+++ b/lib/secure_headers/headers/x_content_type_options.rb
@@ -6,22 +6,20 @@ class XContentTypeOptions
     HEADER_NAME = "x-content-type-options".freeze
     DEFAULT_VALUE = "nosniff"
 
-    class << self
-      # Public: generate an X-Content-Type-Options header.
-      #
-      # Returns a default header if no configuration is provided, or a
-      # header name and value based on the config.
-      def make_header(config = nil, user_agent = nil)
-        return if config == OPT_OUT
-        [HEADER_NAME, config || DEFAULT_VALUE]
-      end
+    # Public: generate an X-Content-Type-Options header.
+    #
+    # Returns a default header if no configuration is provided, or a
+    # header name and value based on the config.
+    def self.make_header(config = nil, user_agent = nil)
+      return if config == OPT_OUT
+      [HEADER_NAME, config || DEFAULT_VALUE]
+    end
 
-      def validate_config!(config)
-        return if config.nil? || config == OPT_OUT
-        raise TypeError.new("Must be a string. Found #{config.class}: #{config}") unless config.is_a?(String)
-        unless config.casecmp(DEFAULT_VALUE) == 0
-          raise XContentTypeOptionsConfigError.new("Value can only be nil or 'nosniff'")
-        end
+    def self.validate_config!(config)
+      return if config.nil? || config == OPT_OUT
+      raise TypeError.new("Must be a string. Found #{config.class}: #{config}") unless config.is_a?(String)
+      unless config.casecmp(DEFAULT_VALUE) == 0
+        raise XContentTypeOptionsConfigError.new("Value can only be nil or 'nosniff'")
       end
     end
   end
diff --git a/lib/secure_headers/headers/x_download_options.rb b/lib/secure_headers/headers/x_download_options.rb
index 1eb1356a..0042e9d0 100644
--- a/lib/secure_headers/headers/x_download_options.rb
+++ b/lib/secure_headers/headers/x_download_options.rb
@@ -5,22 +5,20 @@ class XDownloadOptions
     HEADER_NAME = "x-download-options".freeze
     DEFAULT_VALUE = "noopen"
 
-    class << self
-      # Public: generate an x-download-options header.
-      #
-      # Returns a default header if no configuration is provided, or a
-      # header name and value based on the config.
-      def make_header(config = nil, user_agent = nil)
-        return if config == OPT_OUT
-        [HEADER_NAME, config || DEFAULT_VALUE]
-      end
+    # Public: generate an x-download-options header.
+    #
+    # Returns a default header if no configuration is provided, or a
+    # header name and value based on the config.
+    def self.make_header(config = nil, user_agent = nil)
+      return if config == OPT_OUT
+      [HEADER_NAME, config || DEFAULT_VALUE]
+    end
 
-      def validate_config!(config)
-        return if config.nil? || config == OPT_OUT
-        raise TypeError.new("Must be a string. Found #{config.class}: #{config}") unless config.is_a?(String)
-        unless config.casecmp(DEFAULT_VALUE) == 0
-          raise XDOConfigError.new("Value can only be nil or 'noopen'")
-        end
+    def self.validate_config!(config)
+      return if config.nil? || config == OPT_OUT
+      raise TypeError.new("Must be a string. Found #{config.class}: #{config}") unless config.is_a?(String)
+      unless config.casecmp(DEFAULT_VALUE) == 0
+        raise XDOConfigError.new("Value can only be nil or 'noopen'")
       end
     end
   end
diff --git a/lib/secure_headers/headers/x_frame_options.rb b/lib/secure_headers/headers/x_frame_options.rb
index 636e3bfa..9788ca3e 100644
--- a/lib/secure_headers/headers/x_frame_options.rb
+++ b/lib/secure_headers/headers/x_frame_options.rb
@@ -10,22 +10,20 @@ class XFrameOptions
     DEFAULT_VALUE = SAMEORIGIN
     VALID_XFO_HEADER = /\A(#{SAMEORIGIN}\z|#{DENY}\z|#{ALLOW_ALL}\z|#{ALLOW_FROM}[:\s])/i
 
-    class << self
-      # Public: generate an X-Frame-Options header.
-      #
-      # Returns a default header if no configuration is provided, or a
-      # header name and value based on the config.
-      def make_header(config = nil, user_agent = nil)
-        return if config == OPT_OUT
-        [HEADER_NAME, config || DEFAULT_VALUE]
-      end
+    # Public: generate an X-Frame-Options header.
+    #
+    # Returns a default header if no configuration is provided, or a
+    # header name and value based on the config.
+    def self.make_header(config = nil, user_agent = nil)
+      return if config == OPT_OUT
+      [HEADER_NAME, config || DEFAULT_VALUE]
+    end
 
-      def validate_config!(config)
-        return if config.nil? || config == OPT_OUT
-        raise TypeError.new("Must be a string. Found #{config.class}: #{config}") unless config.is_a?(String)
-        unless config =~ VALID_XFO_HEADER
-          raise XFOConfigError.new("Value must be SAMEORIGIN|DENY|ALLOW-FROM:|ALLOWALL")
-        end
+    def self.validate_config!(config)
+      return if config.nil? || config == OPT_OUT
+      raise TypeError.new("Must be a string. Found #{config.class}: #{config}") unless config.is_a?(String)
+      unless config =~ VALID_XFO_HEADER
+        raise XFOConfigError.new("Value must be SAMEORIGIN|DENY|ALLOW-FROM:|ALLOWALL")
       end
     end
   end
diff --git a/lib/secure_headers/headers/x_permitted_cross_domain_policies.rb b/lib/secure_headers/headers/x_permitted_cross_domain_policies.rb
index a34dd58f..4ca81b68 100644
--- a/lib/secure_headers/headers/x_permitted_cross_domain_policies.rb
+++ b/lib/secure_headers/headers/x_permitted_cross_domain_policies.rb
@@ -6,22 +6,20 @@ class XPermittedCrossDomainPolicies
     DEFAULT_VALUE = "none"
     VALID_POLICIES = %w(all none master-only by-content-type by-ftp-filename)
 
-    class << self
-      # Public: generate an x-permitted-cross-domain-policies header.
-      #
-      # Returns a default header if no configuration is provided, or a
-      # header name and value based on the config.
-      def make_header(config = nil, user_agent = nil)
-        return if config == OPT_OUT
-        [HEADER_NAME, config || DEFAULT_VALUE]
-      end
+    # Public: generate an x-permitted-cross-domain-policies header.
+    #
+    # Returns a default header if no configuration is provided, or a
+    # header name and value based on the config.
+    def self.make_header(config = nil, user_agent = nil)
+      return if config == OPT_OUT
+      [HEADER_NAME, config || DEFAULT_VALUE]
+    end
 
-      def validate_config!(config)
-        return if config.nil? || config == OPT_OUT
-        raise TypeError.new("Must be a string. Found #{config.class}: #{config}") unless config.is_a?(String)
-        unless VALID_POLICIES.include?(config.downcase)
-          raise XPCDPConfigError.new("Value can only be one of #{VALID_POLICIES.join(', ')}")
-        end
+    def self.validate_config!(config)
+      return if config.nil? || config == OPT_OUT
+      raise TypeError.new("Must be a string. Found #{config.class}: #{config}") unless config.is_a?(String)
+      unless VALID_POLICIES.include?(config.downcase)
+        raise XPCDPConfigError.new("Value can only be one of #{VALID_POLICIES.join(', ')}")
       end
     end
   end
diff --git a/lib/secure_headers/headers/x_xss_protection.rb b/lib/secure_headers/headers/x_xss_protection.rb
index bd5b7faa..756bc4c3 100644
--- a/lib/secure_headers/headers/x_xss_protection.rb
+++ b/lib/secure_headers/headers/x_xss_protection.rb
@@ -6,21 +6,19 @@ class XXssProtection
     DEFAULT_VALUE = "0".freeze
     VALID_X_XSS_HEADER = /\A[01](; mode=block)?(; report=.*)?\z/
 
-    class << self
-      # Public: generate an X-Xss-Protection header.
-      #
-      # Returns a default header if no configuration is provided, or a
-      # header name and value based on the config.
-      def make_header(config = nil, user_agent = nil)
-        return if config == OPT_OUT
-        [HEADER_NAME, config || DEFAULT_VALUE]
-      end
+    # Public: generate an X-Xss-Protection header.
+    #
+    # Returns a default header if no configuration is provided, or a
+    # header name and value based on the config.
+    def self.make_header(config = nil, user_agent = nil)
+      return if config == OPT_OUT
+      [HEADER_NAME, config || DEFAULT_VALUE]
+    end
 
-      def validate_config!(config)
-        return if config.nil? || config == OPT_OUT
-        raise TypeError.new("Must be a string. Found #{config.class}: #{config}") unless config.is_a?(String)
-        raise XXssProtectionConfigError.new("Invalid format (see VALID_X_XSS_HEADER)") unless config.to_s =~ VALID_X_XSS_HEADER
-      end
+    def self.validate_config!(config)
+      return if config.nil? || config == OPT_OUT
+      raise TypeError.new("Must be a string. Found #{config.class}: #{config}") unless config.is_a?(String)
+      raise XXssProtectionConfigError.new("Invalid format (see VALID_X_XSS_HEADER)") unless config.to_s =~ VALID_X_XSS_HEADER
     end
   end
 end
diff --git a/spec/lib/secure_headers/configuration_spec.rb b/spec/lib/secure_headers/configuration_spec.rb
index 73e9b16b..fc5f2ec6 100644
--- a/spec/lib/secure_headers/configuration_spec.rb
+++ b/spec/lib/secure_headers/configuration_spec.rb
@@ -22,7 +22,9 @@ module SecureHeaders
       configuration = Configuration.dup
       expect(original_configuration).not_to be(configuration)
       Configuration::CONFIG_ATTRIBUTES.each do |attr|
+        # rubocop:disable GitHub/AvoidObjectSendWithDynamicMethod
         expect(original_configuration.send(attr)).to eq(configuration.send(attr))
+        # rubocop:enable GitHub/AvoidObjectSendWithDynamicMethod
       end
     end
 
@@ -97,7 +99,7 @@ module SecureHeaders
     end
 
     it "gives cookies a default config" do
-      expect(Configuration.default.cookies).to eq({httponly: true, secure: true, samesite: {lax: true}})
+      expect(Configuration.default.cookies).to eq({ httponly: true, secure: true, samesite: { lax: true } })
     end
 
     it "allows OPT_OUT" do
@@ -111,11 +113,11 @@ module SecureHeaders
 
     it "allows me to be explicit too" do
       Configuration.default do |config|
-        config.cookies = {httponly: true, secure: true, samesite: {lax: false}}
+        config.cookies = { httponly: true, secure: true, samesite: { lax: false } }
       end
 
       config = Configuration.dup
-      expect(config.cookies).to eq({httponly: true, secure: true, samesite: {lax: false}})
+      expect(config.cookies).to eq({ httponly: true, secure: true, samesite: { lax: false } })
     end
   end
 end
diff --git a/spec/lib/secure_headers/headers/content_security_policy_spec.rb b/spec/lib/secure_headers/headers/content_security_policy_spec.rb
index 37cb62a7..ed8d8e2b 100644
--- a/spec/lib/secure_headers/headers/content_security_policy_spec.rb
+++ b/spec/lib/secure_headers/headers/content_security_policy_spec.rb
@@ -3,7 +3,7 @@
 
 module SecureHeaders
   describe ContentSecurityPolicy do
-    let (:default_opts) do
+    let(:default_opts) do
       {
         default_src: %w(https:),
         img_src: %w(https: data:),
@@ -167,49 +167,74 @@ module SecureHeaders
       end
 
       it "supports strict-dynamic" do
-        csp = ContentSecurityPolicy.new({default_src: %w('self'), script_src: [ContentSecurityPolicy::STRICT_DYNAMIC], script_nonce: 123456})
+        csp = ContentSecurityPolicy.new({ default_src: %w('self'), script_src: [ContentSecurityPolicy::STRICT_DYNAMIC], script_nonce: 123456 })
         expect(csp.value).to eq("default-src 'self'; script-src 'strict-dynamic' 'nonce-123456' 'unsafe-inline'")
       end
 
       it "supports strict-dynamic and opting out of the appended 'unsafe-inline'" do
-        csp = ContentSecurityPolicy.new({default_src: %w('self'), script_src: [ContentSecurityPolicy::STRICT_DYNAMIC], script_nonce: 123456, disable_nonce_backwards_compatibility: true })
+        csp = ContentSecurityPolicy.new({ default_src: %w('self'), script_src: [ContentSecurityPolicy::STRICT_DYNAMIC], script_nonce: 123456, disable_nonce_backwards_compatibility: true })
         expect(csp.value).to eq("default-src 'self'; script-src 'strict-dynamic' 'nonce-123456'")
       end
 
       it "supports script-src-elem directive" do
-        csp = ContentSecurityPolicy.new({script_src: %w('self'), script_src_elem: %w('self')})
+        csp = ContentSecurityPolicy.new({ script_src: %w('self'), script_src_elem: %w('self') })
         expect(csp.value).to eq("script-src 'self'; script-src-elem 'self'")
       end
 
       it "supports script-src-attr directive" do
-        csp = ContentSecurityPolicy.new({script_src: %w('self'), script_src_attr: %w('self')})
+        csp = ContentSecurityPolicy.new({ script_src: %w('self'), script_src_attr: %w('self') })
         expect(csp.value).to eq("script-src 'self'; script-src-attr 'self'")
       end
 
       it "supports style-src-elem directive" do
-        csp = ContentSecurityPolicy.new({style_src: %w('self'), style_src_elem: %w('self')})
+        csp = ContentSecurityPolicy.new({ style_src: %w('self'), style_src_elem: %w('self') })
         expect(csp.value).to eq("style-src 'self'; style-src-elem 'self'")
       end
 
       it "supports style-src-attr directive" do
-        csp = ContentSecurityPolicy.new({style_src: %w('self'), style_src_attr: %w('self')})
+        csp = ContentSecurityPolicy.new({ style_src: %w('self'), style_src_attr: %w('self') })
         expect(csp.value).to eq("style-src 'self'; style-src-attr 'self'")
       end
 
       it "supports trusted-types directive" do
-        csp = ContentSecurityPolicy.new({trusted_types: %w(blahblahpolicy)})
+        csp = ContentSecurityPolicy.new({ trusted_types: %w(blahblahpolicy) })
         expect(csp.value).to eq("trusted-types blahblahpolicy")
       end
 
       it "supports trusted-types directive with 'none'" do
-        csp = ContentSecurityPolicy.new({trusted_types: %w('none')})
+        csp = ContentSecurityPolicy.new({ trusted_types: %w('none') })
         expect(csp.value).to eq("trusted-types 'none'")
       end
 
       it "allows duplicate policy names in trusted-types directive" do
-        csp = ContentSecurityPolicy.new({trusted_types: %w(blahblahpolicy 'allow-duplicates')})
+        csp = ContentSecurityPolicy.new({ trusted_types: %w(blahblahpolicy 'allow-duplicates') })
         expect(csp.value).to eq("trusted-types blahblahpolicy 'allow-duplicates'")
       end
+
+      it "supports report-to directive with endpoint name" do
+        csp = ContentSecurityPolicy.new({ default_src: %w('self'), report_to: "csp-endpoint" })
+        expect(csp.value).to eq("default-src 'self'; report-to csp-endpoint")
+      end
+
+      it "includes report-to before report-uri in alphabetical order" do
+        csp = ContentSecurityPolicy.new({ default_src: %w('self'), report_uri: %w(/csp_report), report_to: "csp-endpoint" })
+        expect(csp.value).to eq("default-src 'self'; report-to csp-endpoint; report-uri /csp_report")
+      end
+
+      it "does not add report-to if the endpoint name is empty" do
+        csp = ContentSecurityPolicy.new({ default_src: %w('self'), report_to: "" })
+        expect(csp.value).to eq("default-src 'self'")
+      end
+
+      it "does not add report-to if not provided" do
+        csp = ContentSecurityPolicy.new({ default_src: %w('self') })
+        expect(csp.value).not_to include("report-to")
+      end
+
+      it "supports report-to without report-uri" do
+        csp = ContentSecurityPolicy.new({ default_src: %w('self'), report_to: "reporting-endpoint-name" })
+        expect(csp.value).to eq("default-src 'self'; report-to reporting-endpoint-name")
+      end
     end
   end
 end
diff --git a/spec/lib/secure_headers/headers/cookie_spec.rb b/spec/lib/secure_headers/headers/cookie_spec.rb
index cdb24246..b0a9152b 100644
--- a/spec/lib/secure_headers/headers/cookie_spec.rb
+++ b/spec/lib/secure_headers/headers/cookie_spec.rb
@@ -35,7 +35,7 @@ module SecureHeaders
 
       context "when configured with a Hash" do
         it "flags cookies as Secure when whitelisted" do
-          cookie = Cookie.new(raw_cookie, secure: { only: ["_session"]}, httponly: OPT_OUT, samesite: OPT_OUT)
+          cookie = Cookie.new(raw_cookie, secure: { only: ["_session"] }, httponly: OPT_OUT, samesite: OPT_OUT)
           expect(cookie.to_s).to eq("_session=thisisatest; secure")
         end
 
@@ -56,7 +56,7 @@ module SecureHeaders
 
       context "when configured with a Hash" do
         it "flags cookies as HttpOnly when whitelisted" do
-          cookie = Cookie.new(raw_cookie, httponly: { only: ["_session"]}, secure: OPT_OUT, samesite: OPT_OUT)
+          cookie = Cookie.new(raw_cookie, httponly: { only: ["_session"] }, secure: OPT_OUT, samesite: OPT_OUT)
           expect(cookie.to_s).to eq("_session=thisisatest; HttpOnly")
         end
 
@@ -75,7 +75,7 @@ module SecureHeaders
         end
 
         it "flags SameSite=#{flag} when configured with a boolean" do
-          cookie = Cookie.new(raw_cookie, samesite: { flag.downcase.to_sym => true}, secure: OPT_OUT, httponly: OPT_OUT)
+          cookie = Cookie.new(raw_cookie, samesite: { flag.downcase.to_sym => true }, secure: OPT_OUT, httponly: OPT_OUT)
           expect(cookie.to_s).to eq("_session=thisisatest; SameSite=#{flag}")
         end
 
@@ -86,7 +86,7 @@ module SecureHeaders
       end
 
       it "flags SameSite=Strict when configured with a boolean" do
-        cookie = Cookie.new(raw_cookie, {samesite: { strict: true}, secure: OPT_OUT, httponly: OPT_OUT})
+        cookie = Cookie.new(raw_cookie, { samesite: { strict: true }, secure: OPT_OUT, httponly: OPT_OUT })
         expect(cookie.to_s).to eq("_session=thisisatest; SameSite=Strict")
       end
 
@@ -146,7 +146,7 @@ module SecureHeaders
       (cookie_options - [flag]).each do |other_flag|
         it "raises an exception when SameSite #{flag} and #{other_flag} enforcement modes are configured with booleans" do
           expect do
-            Cookie.validate_config!(samesite: { flag => true, other_flag => true})
+            Cookie.validate_config!(samesite: { flag => true, other_flag => true })
           end.to raise_error(CookiesConfigError)
         end
       end
diff --git a/spec/lib/secure_headers/headers/policy_management_spec.rb b/spec/lib/secure_headers/headers/policy_management_spec.rb
index c621e88e..626a1a82 100644
--- a/spec/lib/secure_headers/headers/policy_management_spec.rb
+++ b/spec/lib/secure_headers/headers/policy_management_spec.rb
@@ -8,7 +8,7 @@ module SecureHeaders
       Configuration.default
     end
 
-    let (:default_opts) do
+    let(:default_opts) do
       {
         default_src: %w(https:),
         img_src: %w(https: data:),
@@ -169,6 +169,30 @@ module SecureHeaders
           ContentSecurityPolicy.validate_config!(ContentSecurityPolicyReportOnlyConfig.new(default_opts.merge(report_only: true)))
         end.to_not raise_error
       end
+
+      it "requires report_to to be a string" do
+        expect do
+          ContentSecurityPolicy.validate_config!(ContentSecurityPolicyConfig.new(default_opts.merge(report_to: ["endpoint"])))
+        end.to raise_error(ContentSecurityPolicyConfigError)
+      end
+
+      it "rejects empty report_to endpoint names" do
+        expect do
+          ContentSecurityPolicy.validate_config!(ContentSecurityPolicyConfig.new(default_opts.merge(report_to: "")))
+        end.to raise_error(ContentSecurityPolicyConfigError)
+      end
+
+      it "accepts valid report_to endpoint names" do
+        expect do
+          ContentSecurityPolicy.validate_config!(ContentSecurityPolicyConfig.new(default_opts.merge(report_to: "csp-endpoint")))
+        end.to_not raise_error
+      end
+
+      it "accepts report_to with hyphens and underscores" do
+        expect do
+          ContentSecurityPolicy.validate_config!(ContentSecurityPolicyConfig.new(default_opts.merge(report_to: "csp-endpoint_name-123")))
+        end.to_not raise_error
+      end
     end
 
     describe "#combine_policies" do
diff --git a/spec/lib/secure_headers/headers/reporting_endpoints_spec.rb b/spec/lib/secure_headers/headers/reporting_endpoints_spec.rb
new file mode 100644
index 00000000..286e204c
--- /dev/null
+++ b/spec/lib/secure_headers/headers/reporting_endpoints_spec.rb
@@ -0,0 +1,110 @@
+# frozen_string_literal: true
+require "spec_helper"
+
+module SecureHeaders
+  describe ReportingEndpoints do
+    describe "#make_header" do
+      it "returns nil when config is nil" do
+        expect(ReportingEndpoints.make_header(nil)).to be_nil
+      end
+
+      it "returns nil when config is OPT_OUT" do
+        expect(ReportingEndpoints.make_header(OPT_OUT)).to be_nil
+      end
+
+      it "formats a single endpoint" do
+        config = { "csp-endpoint" => "https://example.com/csp-reports" }
+        header_name, value = ReportingEndpoints.make_header(config)
+        expect(header_name).to eq("reporting-endpoints")
+        expect(value).to eq('csp-endpoint="https://example.com/csp-reports"')
+      end
+
+      it "formats multiple endpoints" do
+        config = {
+          "csp-endpoint" => "https://example.com/csp-reports",
+          "permissions-endpoint" => "https://example.com/permissions-reports"
+        }
+        header_name, value = ReportingEndpoints.make_header(config)
+        expect(header_name).to eq("reporting-endpoints")
+        # Order may vary, so check both endpoints are present
+        expect(value).to include('csp-endpoint="https://example.com/csp-reports"')
+        expect(value).to include('permissions-endpoint="https://example.com/permissions-reports"')
+        expect(value).to include(",")
+      end
+
+      it "validates that endpoints are present" do
+        expect do
+          ReportingEndpoints.validate_config!({})
+        end.to_not raise_error
+      end
+    end
+
+    describe "#validate_config!" do
+      it "accepts nil" do
+        expect do
+          ReportingEndpoints.validate_config!(nil)
+        end.to_not raise_error
+      end
+
+      it "accepts OPT_OUT" do
+        expect do
+          ReportingEndpoints.validate_config!(OPT_OUT)
+        end.to_not raise_error
+      end
+
+      it "accepts valid endpoint configuration" do
+        expect do
+          ReportingEndpoints.validate_config!({
+            "csp-violations" => "https://example.com/reports"
+          })
+        end.to_not raise_error
+      end
+
+      it "rejects non-hash config" do
+        expect do
+          ReportingEndpoints.validate_config!("not a hash")
+        end.to raise_error(TypeError)
+      end
+
+      it "rejects empty endpoint name" do
+        expect do
+          ReportingEndpoints.validate_config!({
+            "" => "https://example.com/reports"
+          })
+        end.to raise_error(ReportingEndpointsConfigError)
+      end
+
+      it "rejects non-string endpoint name" do
+        expect do
+          ReportingEndpoints.validate_config!({
+            123 => "https://example.com/reports"
+          })
+        end.to raise_error(ReportingEndpointsConfigError)
+      end
+
+      it "rejects empty endpoint URL" do
+        expect do
+          ReportingEndpoints.validate_config!({
+            "csp-endpoint" => ""
+          })
+        end.to raise_error(ReportingEndpointsConfigError)
+      end
+
+      it "rejects non-string endpoint URL" do
+        expect do
+          ReportingEndpoints.validate_config!({
+            "csp-endpoint" => 123
+          })
+        end.to raise_error(ReportingEndpointsConfigError)
+      end
+
+      it "rejects non-https URLs" do
+        expect do
+          ReportingEndpoints.validate_config!({
+            "csp-endpoint" => "http://example.com/reports"
+          })
+        end.to raise_error(ReportingEndpointsConfigError, /must use https/)
+      end
+    end
+  end
+end
diff --git a/spec/lib/secure_headers/middleware_spec.rb b/spec/lib/secure_headers/middleware_spec.rb
index b3925f85..f019b597 100644
--- a/spec/lib/secure_headers/middleware_spec.rb
+++ b/spec/lib/secure_headers/middleware_spec.rb
@@ -42,7 +42,7 @@ module SecureHeaders
       end
       context "cookies should be flagged" do
         it "flags cookies as secure" do
-          Configuration.default { |config| config.cookies = {secure: true, httponly: OPT_OUT, samesite: OPT_OUT} }
+          Configuration.default { |config| config.cookies = { secure: true, httponly: OPT_OUT, samesite: OPT_OUT } }
           request = Rack::Request.new("HTTPS" => "on")
           _, env = cookie_middleware.call request.env
           expect(env["Set-Cookie"]).to eq("foo=bar; secure")
@@ -62,7 +62,7 @@ module SecureHeaders
 
       context "cookies should not be flagged" do
         it "does not flags cookies as secure" do
-          Configuration.default { |config| config.cookies = {secure: OPT_OUT, httponly: OPT_OUT, samesite: OPT_OUT}  }
+          Configuration.default { |config| config.cookies = { secure: OPT_OUT, httponly: OPT_OUT, samesite: OPT_OUT }  }
           request = Rack::Request.new("HTTPS" => "on")
           _, env = cookie_middleware.call request.env
           expect(env["Set-Cookie"]).to eq("foo=bar")
@@ -75,7 +75,7 @@ module SecureHeaders
         reset_config
       end
       it "flags cookies from configuration" do
-        Configuration.default { |config| config.cookies = { secure: true, httponly: true, samesite: { lax: true} } }
+        Configuration.default { |config| config.cookies = { secure: true, httponly: true, samesite: { lax: true } } }
         request = Rack::Request.new("HTTPS" => "on")
         _, env = cookie_middleware.call request.env
 
@@ -85,7 +85,7 @@ module SecureHeaders
       it "flags cookies with a combination of SameSite configurations" do
         cookie_middleware = Middleware.new(lambda { |env| [200, env.merge("Set-Cookie" => ["_session=foobar", "_guest=true"]), "app"] })
 
-        Configuration.default { |config| config.cookies = { samesite: { lax: { except: ["_session"] }, strict: { only: ["_session"] } }, httponly: OPT_OUT, secure: OPT_OUT} }
+        Configuration.default { |config| config.cookies = { samesite: { lax: { except: ["_session"] }, strict: { only: ["_session"] } }, httponly: OPT_OUT, secure: OPT_OUT } }
         request = Rack::Request.new("HTTPS" => "on")
         _, env = cookie_middleware.call request.env
 
diff --git a/spec/lib/secure_headers_spec.rb b/spec/lib/secure_headers_spec.rb
index fd66d487..5de8409a 100644
--- a/spec/lib/secure_headers_spec.rb
+++ b/spec/lib/secure_headers_spec.rb
@@ -54,7 +54,7 @@ module SecureHeaders
     describe "#header_hash_for" do
       it "allows you to opt out of individual headers via API" do
         Configuration.default do |config|
-          config.csp = { default_src: %w('self'), script_src: %w('self')}
+          config.csp = { default_src: %w('self'), script_src: %w('self') }
           config.csp_report_only = config.csp
         end
         SecureHeaders.opt_out_of_header(request, :csp)
@@ -174,11 +174,11 @@ module SecureHeaders
           end
 
           Configuration.named_append(:moar_default_sources) do |request|
-            { default_src: %w(https:), style_src: %w('self')}
+            { default_src: %w(https:), style_src: %w('self') }
           end
 
           Configuration.named_append(:how_about_a_script_src_too) do |request|
-            { script_src: %w('unsafe-inline')}
+            { script_src: %w('unsafe-inline') }
           end
 
           SecureHeaders.use_content_security_policy_named_append(request, :moar_default_sources)
@@ -318,7 +318,7 @@ module SecureHeaders
                 default_src: %w('self'),
                 script_src: %w('self')
               }
-              config.csp_report_only = config.csp.merge({script_src: %w(foo.com)})
+              config.csp_report_only = config.csp.merge({ script_src: %w(foo.com) })
             end
 
             hash = SecureHeaders.header_hash_for(request)
@@ -342,42 +342,42 @@ module SecureHeaders
           end
 
           it "allows appending to the enforced policy" do
-            SecureHeaders.append_content_security_policy_directives(request, {script_src: %w(anothercdn.com)}, :enforced)
+            SecureHeaders.append_content_security_policy_directives(request, { script_src: %w(anothercdn.com) }, :enforced)
             hash = SecureHeaders.header_hash_for(request)
             expect(hash["content-security-policy"]).to eq("default-src 'self'; script-src 'self' anothercdn.com")
             expect(hash["content-security-policy-report-only"]).to eq("default-src 'self'; script-src 'self'")
           end
 
           it "allows appending to the report only policy" do
-            SecureHeaders.append_content_security_policy_directives(request, {script_src: %w(anothercdn.com)}, :report_only)
+            SecureHeaders.append_content_security_policy_directives(request, { script_src: %w(anothercdn.com) }, :report_only)
             hash = SecureHeaders.header_hash_for(request)
             expect(hash["content-security-policy"]).to eq("default-src 'self'; script-src 'self'")
             expect(hash["content-security-policy-report-only"]).to eq("default-src 'self'; script-src 'self' anothercdn.com")
           end
 
           it "allows appending to both policies" do
-            SecureHeaders.append_content_security_policy_directives(request, {script_src: %w(anothercdn.com)}, :both)
+            SecureHeaders.append_content_security_policy_directives(request, { script_src: %w(anothercdn.com) }, :both)
             hash = SecureHeaders.header_hash_for(request)
             expect(hash["content-security-policy"]).to eq("default-src 'self'; script-src 'self' anothercdn.com")
             expect(hash["content-security-policy-report-only"]).to eq("default-src 'self'; script-src 'self' anothercdn.com")
           end
 
           it "allows overriding the enforced policy" do
-            SecureHeaders.override_content_security_policy_directives(request, {script_src: %w(anothercdn.com)}, :enforced)
+            SecureHeaders.override_content_security_policy_directives(request, { script_src: %w(anothercdn.com) }, :enforced)
             hash = SecureHeaders.header_hash_for(request)
             expect(hash["content-security-policy"]).to eq("default-src 'self'; script-src anothercdn.com")
             expect(hash["content-security-policy-report-only"]).to eq("default-src 'self'; script-src 'self'")
           end
 
           it "allows overriding the report only policy" do
-            SecureHeaders.override_content_security_policy_directives(request, {script_src: %w(anothercdn.com)}, :report_only)
+            SecureHeaders.override_content_security_policy_directives(request, { script_src: %w(anothercdn.com) }, :report_only)
             hash = SecureHeaders.header_hash_for(request)
             expect(hash["content-security-policy"]).to eq("default-src 'self'; script-src 'self'")
             expect(hash["content-security-policy-report-only"]).to eq("default-src 'self'; script-src anothercdn.com")
           end
 
           it "allows overriding both policies" do
-            SecureHeaders.override_content_security_policy_directives(request, {script_src: %w(anothercdn.com)}, :both)
+            SecureHeaders.override_content_security_policy_directives(request, { script_src: %w(anothercdn.com) }, :both)
             hash = SecureHeaders.header_hash_for(request)
             expect(hash["content-security-policy"]).to eq("default-src 'self'; script-src anothercdn.com")
             expect(hash["content-security-policy-report-only"]).to eq("default-src 'self'; script-src anothercdn.com")
@@ -392,7 +392,7 @@ module SecureHeaders
                   script_src: %w('self')
                 }
               end
-              SecureHeaders.append_content_security_policy_directives(request, {script_src: %w(anothercdn.com)})
+              SecureHeaders.append_content_security_policy_directives(request, { script_src: %w(anothercdn.com) })
 
               hash = SecureHeaders.header_hash_for(request)
               expect(hash["content-security-policy"]).to eq("default-src 'self'; script-src 'self' anothercdn.com")
@@ -408,7 +408,7 @@ module SecureHeaders
                   script_src: %w('self')
                 }
               end
-              SecureHeaders.append_content_security_policy_directives(request, {script_src: %w(anothercdn.com)})
+              SecureHeaders.append_content_security_policy_directives(request, { script_src: %w(anothercdn.com) })
 
               hash = SecureHeaders.header_hash_for(request)
               expect(hash["content-security-policy-report-only"]).to eq("default-src 'self'; script-src 'self' anothercdn.com")
@@ -427,7 +427,7 @@ module SecureHeaders
                   script_src: %w('self')
                 }
               end
-              SecureHeaders.append_content_security_policy_directives(request, {script_src: %w(anothercdn.com)})
+              SecureHeaders.append_content_security_policy_directives(request, { script_src: %w(anothercdn.com) })
 
               hash = SecureHeaders.header_hash_for(request)
               expect(hash["content-security-policy"]).to eq("default-src enforced.com; script-src 'self' anothercdn.com")
@@ -527,6 +527,146 @@ module SecureHeaders
           end
         end.to raise_error(CookiesConfigError)
       end
+
+      it "validates report_to directive on configuration" do
+        expect do
+          Configuration.default do |config|
+            config.csp = {
+              default_src: %w('self'),
+              script_src: %w('self'),
+              report_to: ["not_a_string"]
+            }
+          end
+        end.to raise_error(ContentSecurityPolicyConfigError)
+      end
+
+      it "allows report_to directive with string endpoint" do
+        expect do
+          Configuration.default do |config|
+            config.csp = {
+              default_src: %w('self'),
+              script_src: %w('self'),
+              report_to: "csp-endpoint"
+            }
+          end
+        end.to_not raise_error
+      end
+    end
+
+    describe "report_to with overrides and appends" do
+      let(:request) { double("Request", scheme: "https", env: {}) }
+
+      it "overrides the report_to directive" do
+        Configuration.default do |config|
+          config.csp = {
+            default_src: %w('self'),
+            script_src: %w('self'),
+            report_to: "endpoint-1"
+          }
+        end
+
+        SecureHeaders.override_content_security_policy_directives(request, report_to: "endpoint-2")
+        headers = SecureHeaders.header_hash_for(request)
+        csp_header = headers[ContentSecurityPolicyConfig::HEADER_NAME]
+        expect(csp_header).to include("report-to endpoint-2")
+      end
+
+      it "includes report_to when appending CSP directives" do
+        Configuration.default do |config|
+          config.csp = {
+            default_src: %w('self'),
+            script_src: %w('self')
+          }
+        end
+
+        SecureHeaders.append_content_security_policy_directives(request, report_to: "new-endpoint")
+        headers = SecureHeaders.header_hash_for(request)
+        csp_header = headers[ContentSecurityPolicyConfig::HEADER_NAME]
+        expect(csp_header).to include("report-to new-endpoint")
+      end
+
+      it "handles report_to with report_uri together" do
+        Configuration.default do |config|
+          config.csp = {
+            default_src: %w('self'),
+            script_src: %w('self'),
+            report_uri: %w(/csp-report),
+            report_to: "reporting-endpoint"
+          }
+        end
+
+        headers = SecureHeaders.header_hash_for(request)
+        csp_header = headers[ContentSecurityPolicyConfig::HEADER_NAME]
+        # Both should be present
+        expect(csp_header).to include("report-to reporting-endpoint")
+        expect(csp_header).to include("report-uri /csp-report")
+        # report-to should come before report-uri (alphabetical order)
+        expect(csp_header.index("report-to")).to be < csp_header.index("report-uri")
+      end
+    end
+
+    describe "reporting_endpoints header generation" do
+      let(:request) { double("Request", scheme: "https", env: {}) }
+
+      before(:each) do
+        reset_config
+      end
+
+      it "includes reporting_endpoints header in generated headers" do
+        Configuration.default do |config|
+          config.csp = {
+            default_src: %w('self'),
+            script_src: %w('self')
+          }
+          config.reporting_endpoints = {
+            "csp-endpoint" => "https://example.com/reports"
+          }
+        end
+
+        headers = SecureHeaders.header_hash_for(request)
+        expect(headers["reporting-endpoints"]).to eq('csp-endpoint="https://example.com/reports"')
+      end
+
+      it "includes reporting_endpoints after config.dup() is called" do
+        # This test specifically validates that reporting_endpoints survives
+        # the .dup() call made by the middleware
+        Configuration.default do |config|
+          config.csp = {
+            default_src: %w('self'),
+            script_src: %w('self')
+          }
+          config.reporting_endpoints = {
+            "csp-violations" => "https://api.example.com/reports?enforcement=enforce",
+            "csp-violations-report-only" => "https://api.example.com/reports?enforcement=report-only"
+          }
+        end
+
+        # Simulate what the middleware does internally
+        config = Configuration.dup  # ← This calls .dup() which must preserve reporting_endpoints
+        headers = config.generate_headers
+
+        expect(headers["reporting-endpoints"]).to include('csp-violations="https://api.example.com/reports?enforcement=enforce"')
+        expect(headers["reporting-endpoints"]).to include('csp-violations-report-only="https://api.example.com/reports?enforcement=report-only"')
+      end
+
+      it "does not include reporting_endpoints header when OPT_OUT" do
+        Configuration.default do |config|
+          config.csp = { default_src: %w('self'), script_src: %w('self') }
+          config.reporting_endpoints = OPT_OUT
+        end
+
+        headers = SecureHeaders.header_hash_for(request)
+        expect(headers["reporting-endpoints"]).to be_nil
+      end
+
+      it "does not include reporting_endpoints header when not configured" do
+        Configuration.default do |config|
+          config.csp = { default_src: %w('self'), script_src: %w('self') }
+        end
+
+        headers = SecureHeaders.header_hash_for(request)
+        expect(headers["reporting-endpoints"]).to be_nil
+      end
     end
   end
 end
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index b0c774d9..65627eec 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -41,18 +41,16 @@ def expect_default_values(hash)
 
 module SecureHeaders
   class Configuration
-    class << self
-      def clear_default_config
-        remove_instance_variable(:@default_config) if defined?(@default_config)
-      end
+    def self.clear_default_config
+      remove_instance_variable(:@default_config) if defined?(@default_config)
+    end
 
-      def clear_overrides
-        remove_instance_variable(:@overrides) if defined?(@overrides)
-      end
+    def self.clear_overrides
+      remove_instance_variable(:@overrides) if defined?(@overrides)
+    end
 
-      def clear_appends
-        remove_instance_variable(:@appends) if defined?(@appends)
-      end
+    def self.clear_appends
+      remove_instance_variable(:@appends) if defined?(@appends)
     end
   end
 end