diff --git a/.gitignore b/.gitignore
index c3f71e6055..a8d86c558c 100644
--- a/.gitignore
+++ b/.gitignore
@@ -11,7 +11,6 @@ log
 .sass-cache
 spec/dummy/app/assets/builds/*
 !spec/dummy/app/assets/builds/.keep
-spec/dummy/config/alchemy/config.yml
 spec/dummy/db/*.sqlite3*
 spec/dummy/postcss.config.js
 spec/dummy/public/assets/
diff --git a/README.md b/README.md
index d2692751fb..787d160d5b 100644
--- a/README.md
+++ b/README.md
@@ -246,7 +246,7 @@ $ bin/rake alchemy:upgrade
 Alchemy will print out useful information after running the automated tasks that help a smooth upgrade path.
 So please **take your time and read them**.
 
-Always be sure to keep an eye on the `config/alchemy/config.yml.defaults` file and update your `config/alchemy/config.yml` accordingly.
+Always be sure to keep an eye on the output of your Rails app when starting. There will probably be useful information about deprecations.
 
 Also, `git diff` is your friend.
 
diff --git a/app/controllers/alchemy/admin/languages_controller.rb b/app/controllers/alchemy/admin/languages_controller.rb
index ee487b3129..e33059cdb1 100644
--- a/app/controllers/alchemy/admin/languages_controller.rb
+++ b/app/controllers/alchemy/admin/languages_controller.rb
@@ -14,7 +14,7 @@ def index
       def new
         @language = Language.new(
           site: @current_site,
-          page_layout: Config.get(:default_language)["page_layout"]
+          page_layout: Alchemy.config.get(:default_language)["page_layout"]
         )
       end
 
diff --git a/app/controllers/alchemy/admin/pages_controller.rb b/app/controllers/alchemy/admin/pages_controller.rb
index 986878eecd..1749cf4a57 100644
--- a/app/controllers/alchemy/admin/pages_controller.rb
+++ b/app/controllers/alchemy/admin/pages_controller.rb
@@ -69,7 +69,7 @@ def show
         Current.preview_page = @page
         # Setting the locale to pages language, so the page content has it's correct translations.
         ::I18n.locale = @page.language.locale
-        render(layout: Alchemy::Config.get(:admin_page_preview_layout) || "application")
+        render(layout: Alchemy.config.get(:admin_page_preview_layout) || "application")
       end
 
       def info
diff --git a/app/controllers/alchemy/admin/resources_controller.rb b/app/controllers/alchemy/admin/resources_controller.rb
index ed5749dedb..9e9a1e7ab6 100644
--- a/app/controllers/alchemy/admin/resources_controller.rb
+++ b/app/controllers/alchemy/admin/resources_controller.rb
@@ -224,11 +224,11 @@ def permitted_ransack_search_fields
 
       def items_per_page
         cookies[:alchemy_items_per_page] =
-          params[:per_page] || cookies[:alchemy_items_per_page] || Alchemy::Config.get(:items_per_page)
+          params[:per_page] || cookies[:alchemy_items_per_page] || Alchemy.config.get(:items_per_page)
       end
 
       def items_per_page_options
-        per_page = Alchemy::Config.get(:items_per_page)
+        per_page = Alchemy.config.get(:items_per_page)
         [per_page, per_page * 2, per_page * 4]
       end
 
diff --git a/app/controllers/alchemy/messages_controller.rb b/app/controllers/alchemy/messages_controller.rb
index b84ac401d2..388ebe4304 100644
--- a/app/controllers/alchemy/messages_controller.rb
+++ b/app/controllers/alchemy/messages_controller.rb
@@ -74,7 +74,7 @@ def create # :nodoc:
     private
 
     def mailer_config
-      Alchemy::Config.get(:mailer)
+      Alchemy.config.get(:mailer)
     end
 
     def mail_to
diff --git a/app/helpers/alchemy/admin/base_helper.rb b/app/helpers/alchemy/admin/base_helper.rb
index 9326f052a1..e9d0f8839e 100644
--- a/app/helpers/alchemy/admin/base_helper.rb
+++ b/app/helpers/alchemy/admin/base_helper.rb
@@ -273,7 +273,7 @@ def clipboard_select_tag_options(items)
 
       # Returns the regular expression used for external url validation in link dialog.
       def link_url_regexp
-        Alchemy::Config.get(:format_matchers)["link_url"] || /^(mailto:|\/|[a-z]+:\/\/)/
+        Alchemy.config.get(:format_matchers)["link_url"] || /^(mailto:|\/|[a-z]+:\/\/)/
       end
 
       # Renders a hint with tooltip
diff --git a/app/helpers/alchemy/admin/pages_helper.rb b/app/helpers/alchemy/admin/pages_helper.rb
index fe502e91c3..957c247221 100644
--- a/app/helpers/alchemy/admin/pages_helper.rb
+++ b/app/helpers/alchemy/admin/pages_helper.rb
@@ -10,7 +10,7 @@ module PagesHelper
       # You can configure the screen sizes in your +config/alchemy/config.yml+.
       #
       def preview_sizes_for_select
-        Alchemy::Config.get(:page_preview_sizes).map do |size|
+        Alchemy.config.get(:page_preview_sizes).map do |size|
           [Alchemy.t(size, scope: "preview_sizes"), size]
         end
       end
diff --git a/app/models/alchemy/attachment.rb b/app/models/alchemy/attachment.rb
index d0d76c9edd..251edb5023 100644
--- a/app/models/alchemy/attachment.rb
+++ b/app/models/alchemy/attachment.rb
@@ -83,12 +83,12 @@ def searchable_alchemy_resource_attributes
       end
 
       def allowed_filetypes
-        Config.get(:uploader).fetch("allowed_filetypes", {}).fetch("alchemy/attachments", [])
+        Alchemy.config.get(:uploader).fetch("allowed_filetypes", {}).fetch("alchemy/attachments", [])
       end
     end
 
     validates_presence_of :file
-    validates_size_of :file, maximum: Config.get(:uploader)["file_size_limit"].megabytes
+    validates_size_of :file, maximum: Alchemy.config.get(:uploader)["file_size_limit"].megabytes
     validates_property :ext,
       of: :file,
       in: allowed_filetypes,
diff --git a/app/models/alchemy/base_record.rb b/app/models/alchemy/base_record.rb
index 58e7044d9e..c005a18344 100644
--- a/app/models/alchemy/base_record.rb
+++ b/app/models/alchemy/base_record.rb
@@ -6,6 +6,8 @@ def self.table_name_prefix
   end
 
   class BaseRecord < ActiveRecord::Base
+    include ConfigMissing
+    extend ConfigMissing
     extend Alchemy::SearchableResource
 
     self.abstract_class = true
diff --git a/app/models/alchemy/ingredient_validator.rb b/app/models/alchemy/ingredient_validator.rb
index a49015e97d..53ef6b07a4 100644
--- a/app/models/alchemy/ingredient_validator.rb
+++ b/app/models/alchemy/ingredient_validator.rb
@@ -80,8 +80,12 @@ def validate_uniqueness(*)
     end
 
     def validate_format(format)
-      matcher = Alchemy::Config.get("format_matchers")[format] || format
-      if !ingredient.value.to_s.match?(Regexp.new(matcher))
+      matcher = if format.is_a?(String) || format.is_a?(Symbol)
+        Alchemy.config.get("format_matchers").get(format)
+      else
+        format
+      end
+      if !ingredient.value.to_s.match?(matcher)
         ingredient.errors.add(:value, :invalid)
       end
     end
diff --git a/app/models/alchemy/message.rb b/app/models/alchemy/message.rb
index 64326e07c5..3ea9a42687 100644
--- a/app/models/alchemy/message.rb
+++ b/app/models/alchemy/message.rb
@@ -17,7 +17,7 @@ class Message
     include ActiveModel::Model
 
     def self.config
-      Alchemy::Config.get(:mailer)
+      Alchemy.config.get(:mailer)
     end
 
     attr_accessor :contact_form_id, :ip
@@ -32,7 +32,7 @@ def self.config
       case field.to_sym
       when /email/
         validates_format_of field,
-          with: Alchemy::Config.get("format_matchers")["email"],
+          with: Alchemy.config.get("format_matchers")["email"],
           if: -> { send(field).present? }
       when :email_confirmation
         validates_confirmation_of :email
diff --git a/app/models/alchemy/page.rb b/app/models/alchemy/page.rb
index 8d4666d40a..97648054f9 100644
--- a/app/models/alchemy/page.rb
+++ b/app/models/alchemy/page.rb
@@ -257,7 +257,7 @@ def all_from_clipboard_for_select(clipboard, language_id, layoutpages: false)
 
       def link_target_options
         options = [[Alchemy.t(:default, scope: "link_target_options"), ""]]
-        link_target_options = Config.get(:link_target_options)
+        link_target_options = Alchemy.config.get(:link_target_options)
         link_target_options.each do |option|
           # add an underscore to the options to provide the default syntax
           # @link https://developer.mozilla.org/en-US/docs/Web/HTML/Element/a#target
diff --git a/app/models/alchemy/page/page_natures.rb b/app/models/alchemy/page/page_natures.rb
index e42cdc5c3e..413500ed07 100644
--- a/app/models/alchemy/page/page_natures.rb
+++ b/app/models/alchemy/page/page_natures.rb
@@ -153,7 +153,7 @@ def cache_page?
       private
 
       def caching_enabled?
-        Alchemy::Config.get(:cache_pages) &&
+        Alchemy.config.get(:cache_pages) &&
           Rails.application.config.action_controller.perform_caching
       end
     end
diff --git a/app/models/alchemy/picture.rb b/app/models/alchemy/picture.rb
index 11b6185904..84b0013869 100644
--- a/app/models/alchemy/picture.rb
+++ b/app/models/alchemy/picture.rb
@@ -100,12 +100,12 @@ def self.preprocessor_class=(klass)
     # We need to define this method here to have it available in the validations below.
     class << self
       def allowed_filetypes
-        Config.get(:uploader).fetch("allowed_filetypes", {}).fetch("alchemy/pictures", [])
+        Alchemy.config.get(:uploader).fetch("allowed_filetypes", {}).fetch("alchemy/pictures", [])
       end
     end
 
     validates_presence_of :image_file
-    validates_size_of :image_file, maximum: Config.get(:uploader)["file_size_limit"].megabytes
+    validates_size_of :image_file, maximum: Alchemy.config.get(:uploader)["file_size_limit"].megabytes
     validates_property :format,
       of: :image_file,
       in: allowed_filetypes,
@@ -260,7 +260,7 @@ def humanized_name
     #
     def default_render_format
       if convertible?
-        Config.get(:image_output_format)
+        Alchemy.config.get(:image_output_format)
       else
         image_file_format
       end
@@ -272,8 +272,8 @@ def default_render_format
     # image has not a convertible file format (i.e. SVG) this returns +false+
     #
     def convertible?
-      Config.get(:image_output_format) &&
-        Config.get(:image_output_format) != "original" &&
+      Alchemy.config.get(:image_output_format) &&
+        Alchemy.config.get(:image_output_format) != "original" &&
         has_convertible_format?
     end
 
diff --git a/app/models/alchemy/picture/preprocessor.rb b/app/models/alchemy/picture/preprocessor.rb
index 86d2869602..7584256788 100644
--- a/app/models/alchemy/picture/preprocessor.rb
+++ b/app/models/alchemy/picture/preprocessor.rb
@@ -9,12 +9,12 @@ def initialize(image_file)
 
       # Preprocess images after upload
       #
-      # Define preprocessing options in the Alchemy::Config
+      # Define preprocessing options in the Alchemy.config
       #
       #   preprocess_image_resize [String] - Downsizing example: '1000x1000>'
       #
       def call
-        max_image_size = Alchemy::Config.get(:preprocess_image_resize)
+        max_image_size = Alchemy.config.get(:preprocess_image_resize)
         image_file.thumb!(max_image_size) if max_image_size.present?
         # Auto orient the image so EXIF orientation data is taken into account
         image_file.auto_orient!
diff --git a/app/models/alchemy/picture_variant.rb b/app/models/alchemy/picture_variant.rb
index 8e2f291d75..4d074f285b 100644
--- a/app/models/alchemy/picture_variant.rb
+++ b/app/models/alchemy/picture_variant.rb
@@ -97,7 +97,7 @@ def encoded_image(image, options = {})
       convert_format = render_format.sub("jpeg", "jpg") != picture.image_file_format.sub("jpeg", "jpg")
 
       if encodable_image? && (convert_format || options[:quality])
-        quality = options[:quality] || Config.get(:output_image_quality)
+        quality = options[:quality] || Alchemy.config.get(:output_image_quality)
         encoding_options << "-quality #{quality}"
       end
 
diff --git a/app/models/concerns/alchemy/picture_thumbnails.rb b/app/models/concerns/alchemy/picture_thumbnails.rb
index aa4e907233..4c6d6485d5 100644
--- a/app/models/concerns/alchemy/picture_thumbnails.rb
+++ b/app/models/concerns/alchemy/picture_thumbnails.rb
@@ -28,7 +28,7 @@ module PictureThumbnails
     #
     # @option options format [String]
     #   The format the picture should be rendered in.
-    #   Defaults to the +image_output_format+ from the +Alchemy::Config+.
+    #   Defaults to the +image_output_format+ from the +Alchemy.config+.
     #
     # @option options crop [Boolean]
     #   If set to true the picture will be cropped to fit the size value.
diff --git a/app/views/alchemy/admin/languages/index.html.erb b/app/views/alchemy/admin/languages/index.html.erb
index 9d2f68aa38..e412554bde 100644
--- a/app/views/alchemy/admin/languages/index.html.erb
+++ b/app/views/alchemy/admin/languages/index.html.erb
@@ -31,12 +31,15 @@
         <%== Alchemy.t('alchemy/language', scope: :no_resource_found) %>
       <% end %>
       <%= render 'form', language: Alchemy::Language.new(
-        Alchemy::Config.get(:default_language).merge(
+          name: Alchemy.config.default_language.name,
+          code: Alchemy.config.default_language.code,
+          page_layout: Alchemy.config.default_language.page_layout,
+          frontpage_name: Alchemy.config.default_language.frontpage_name,
           site: Alchemy::Current.site,
           default: true,
           public: true
         )
-      ) %>
+       %>
     </div>
   <% end %>
 </div>
diff --git a/app/views/alchemy/admin/sites/index.html.erb b/app/views/alchemy/admin/sites/index.html.erb
index b084ddd532..ef2c7004e4 100644
--- a/app/views/alchemy/admin/sites/index.html.erb
+++ b/app/views/alchemy/admin/sites/index.html.erb
@@ -30,7 +30,11 @@
       <%= render_message do %>
         <%== Alchemy.t('alchemy/site', scope: :no_resource_found) %>
       <% end %>
-      <%= render 'form', site: Alchemy::Site.new(Alchemy::Config.get(:default_site).merge(public: true)) %>
+      <%= render 'form', site: Alchemy::Site.new(
+          name: Alchemy.config.default_site.name,
+          host: Alchemy.config.default_site.host,
+          public: true
+        ) %>
     </div>
   <% end %>
 </div>
diff --git a/lib/alchemy.rb b/lib/alchemy.rb
index a3703e1a32..4bf0cd7817 100644
--- a/lib/alchemy.rb
+++ b/lib/alchemy.rb
@@ -2,10 +2,23 @@
 
 require "alchemy/admin/preview_url"
 require "importmap-rails"
+require "alchemy/configurations/main"
+require "alchemy/config_missing"
 
 module Alchemy
+  include Alchemy::ConfigMissing
+  extend Alchemy::ConfigMissing
+
   YAML_PERMITTED_CLASSES = %w[Symbol Date Regexp]
 
+  def self.config
+    @_config ||= Alchemy::Configurations::Main.new
+  end
+
+  def self.configure(&blk)
+    yield config
+  end
+
   # Define page preview sources
   #
   # A preview source is a Ruby class returning an URL
diff --git a/lib/alchemy/admin/preview_url.rb b/lib/alchemy/admin/preview_url.rb
index dba6d96ff1..9408c579e8 100644
--- a/lib/alchemy/admin/preview_url.rb
+++ b/lib/alchemy/admin/preview_url.rb
@@ -41,7 +41,6 @@ def initialize(routes:)
 
       def url_for(page)
         @preview_config = preview_config_for(page)
-
         if @preview_config && uri
           uri_class.build(
             host: uri.host,
@@ -60,10 +59,10 @@ def url_for(page)
       attr_reader :routes
 
       def preview_config_for(page)
-        preview_config = Alchemy::Config.get(:preview)
+        preview_config = Alchemy.config.preview
         return unless preview_config
 
-        preview_config[page.site.name] || preview_config
+        preview_config.for_site(page.site) || preview_config
       end
 
       def uri
@@ -81,8 +80,8 @@ def uri_class
       end
 
       def userinfo
-        auth = @preview_config["auth"]
-        auth ? "#{auth["username"]}:#{auth["password"]}" : nil
+        auth = @preview_config.auth
+        auth.username ? "#{auth["username"]}:#{auth["password"]}" : nil
       end
     end
   end
diff --git a/lib/alchemy/config.rb b/lib/alchemy/config.rb
deleted file mode 100644
index 127edb0e42..0000000000
--- a/lib/alchemy/config.rb
+++ /dev/null
@@ -1,114 +0,0 @@
-# frozen_string_literal: true
-
-module Alchemy
-  class Config
-    class << self
-      # Returns the configuration for given parameter name.
-      #
-      # @param name [String]
-      #
-      def get(name)
-        check_deprecation(name)
-        key = check_replacement(name)
-        show[key.to_s]
-      end
-
-      alias_method :parameter, :get
-
-      # Returns a merged configuration of the following files
-      #
-      # Alchemys default config: +gems/../alchemy_cms/config/alchemy/config.yml+
-      # Your apps default config: +your_app/config/alchemy/config.yml+
-      # Environment specific config: +your_app/config/alchemy/development.config.yml+
-      #
-      # An environment specific config overwrites the settings of your apps default config,
-      # while your apps default config has precedence over Alchemys default config.
-      #
-      def show
-        @config ||= merge_configs!(alchemy_config, main_app_config, env_specific_config)
-      end
-
-      # A list of deprecated configuration values
-      # a value of nil means there is no new default
-      # any not nil value is the new default
-      def deprecated_configs
-        {}
-      end
-
-      # A list of replaced configuration keys
-      def replaced_config_keys
-        {
-          output_image_quality: :output_image_jpg_quality
-        }
-      end
-
-      private
-
-      # Alchemy default configuration
-      def alchemy_config
-        read_file Engine.root.join("config/alchemy/config.yml")
-      end
-
-      # Application specific configuration
-      def main_app_config
-        read_file Rails.root.join("config/alchemy/config.yml")
-      end
-
-      # Rails Environment specific configuration
-      def env_specific_config
-        read_file Rails.root.join("config/alchemy/#{Rails.env}.config.yml")
-      end
-
-      # Tries to load yaml file from given path.
-      # If it does not exist, or its empty, it returns an empty Hash.
-      #
-      def read_file(file)
-        YAML.safe_load(
-          ERB.new(File.read(file)).result,
-          permitted_classes: YAML_PERMITTED_CLASSES,
-          aliases: true
-        ) || {}
-      rescue Errno::ENOENT
-        {}
-      end
-
-      # Merges all given configs together
-      #
-      def merge_configs!(*config_files)
-        raise LoadError, "No Alchemy config file found!" if config_files.map(&:blank?).all?
-
-        config = {}
-        config_files.each { |h| config.merge!(h.stringify_keys!) }
-        config
-      end
-
-      def check_deprecation(name)
-        if deprecated_configs.key?(name.to_sym)
-          config = deprecated_configs[name.to_sym]
-          if config.nil?
-            Alchemy::Deprecation.warn("#{name} configuration is deprecated and will be removed from Alchemy #{Alchemy::Deprecation.deprecation_horizon}")
-          else
-            value = show[name.to_s]
-            if value != config
-              Alchemy::Deprecation.warn("Setting #{name} configuration to #{value} is deprecated and will be always #{config} in Alchemy #{Alchemy::Deprecation.deprecation_horizon}")
-            end
-          end
-        end
-      end
-
-      def check_replacement(name)
-        if replaced_config_keys.key?(name.to_sym)
-          old_key = replaced_config_keys[name.to_sym]
-          if show[old_key.to_s]
-            Alchemy::Deprecation.warn("Using #{old_key} configuration is deprecated and will be removed in Alchemy #{Alchemy::Deprecation.deprecation_horizon}. Please use #{name} instead.")
-            old_key
-          else
-            name
-          end
-        else
-          name
-        end
-      end
-    end
-  end
-end
diff --git a/lib/alchemy/config_missing.rb b/lib/alchemy/config_missing.rb
new file mode 100644
index 0000000000..2aed42bc87
--- /dev/null
+++ b/lib/alchemy/config_missing.rb
@@ -0,0 +1,14 @@
+# frozen_string_literal: true
+
+module Alchemy
+  module ConfigMissing
+    def const_missing(missing_const_name)
+      if missing_const_name == :Config
+        Alchemy::Deprecation.warn("Alchemy::Config is deprecated. Use Alchemy.config instead.")
+        Alchemy.config
+      else
+        super
+      end
+    end
+  end
+end
diff --git a/lib/alchemy/configuration.rb b/lib/alchemy/configuration.rb
new file mode 100644
index 0000000000..3c0503ca75
--- /dev/null
+++ b/lib/alchemy/configuration.rb
@@ -0,0 +1,115 @@
+# frozen_string_literal: true
+
+require "active_support"
+require "active_support/core_ext/string"
+
+require "alchemy/configuration/boolean_option"
+require "alchemy/configuration/class_option"
+require "alchemy/configuration/class_set_option"
+require "alchemy/configuration/integer_option"
+require "alchemy/configuration/integer_list_option"
+require "alchemy/configuration/regexp_option"
+require "alchemy/configuration/string_list_option"
+require "alchemy/configuration/string_option"
+
+module Alchemy
+  class Configuration
+    def initialize(configuration_hash = {})
+      set(configuration_hash)
+    end
+
+    def set(configuration_hash)
+      configuration_hash.each do |key, value|
+        send(:"#{key}=", value)
+      end
+    end
+
+    alias_method :get, :send
+    alias_method :[], :get
+
+    def show = self
+
+    def fetch(key, default = nil)
+      get(key) || default
+    end
+
+    def set_from_yaml(file)
+      set(
+        YAML.safe_load(
+          ERB.new(File.read(file)).result,
+          permitted_classes: YAML_PERMITTED_CLASSES,
+          aliases: true
+        ) || {}
+      )
+    end
+
+    def to_h
+      self.class.defined_options.map do |option|
+        [option, send(option)]
+      end.concat(
+        self.class.defined_configurations.map do |configuration|
+          [configuration, send(configuration).to_h]
+        end
+      ).to_h
+    end
+
+    class << self
+      def defined_configurations = []
+
+      def defined_options = []
+
+      def configuration(name, configuration_class)
+        # The defined configurations on a class are all those defined directly on
+        # that class as well as those defined on ancestors.
+        # We store these as a class instance variable on each class which has a
+        # configuration. super() collects configurations defined on ancestors.
+        singleton_configurations = (@defined_singleton_configurations ||= [])
+        singleton_configurations << name.to_sym
+
+        define_singleton_method :defined_configurations do
+          super() + singleton_configurations
+        end
+
+        define_method(name) do
+          unless instance_variable_get(:"@#{name}")
+            send(:"#{name}=", configuration_class.new)
+          end
+          instance_variable_get(:"@#{name}")
+        end
+
+        define_method(:"#{name}=") do |value|
+          if value.is_a?(configuration_class)
+            instance_variable_set(:"@#{name}", value)
+          else
+            send(name).set(value)
+          end
+        end
+      end
+
+      def option(name, type, default: nil, **args)
+        klass = "Alchemy::Configuration::#{type.to_s.camelize}Option".constantize
+        # The defined options on a class are all those defined directly on
+        # that class as well as those defined on ancestors.
+        # We store these as a class instance variable on each class which has a
+        # option. super() collects options defined on ancestors.
+        singleton_options = (@defined_singleton_options ||= [])
+        singleton_options << name.to_sym
+
+        define_singleton_method :defined_options do
+          super() + singleton_options
+        end
+
+        define_method(name) do
+          unless instance_variable_defined?(:"@#{name}")
+            send(:"#{name}=", default)
+          end
+          instance_variable_get(:"@#{name}").value
+        end
+
+        define_method(:"#{name}=") do |value|
+          instance_variable_set(:"@#{name}", klass.new(value:, name:, **args))
+        end
+      end
+    end
+  end
+end
diff --git a/lib/alchemy/configuration/base_option.rb b/lib/alchemy/configuration/base_option.rb
new file mode 100644
index 0000000000..8baca65269
--- /dev/null
+++ b/lib/alchemy/configuration/base_option.rb
@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+module Alchemy
+  class Configuration
+    class BaseOption
+      def self.value_class
+        raise NotImplementedError
+      end
+
+      def initialize(value:, name:, **args)
+        @name = name
+        @value = validate(value) if value
+      end
+      attr_reader :name, :value
+
+      private
+
+      def validate(value)
+        raise TypeError, "#{name} must be set as a #{self.class.value_class.name}, given #{value.inspect}" unless value.is_a?(self.class.value_class)
+        value
+      end
+    end
+  end
+end
diff --git a/lib/alchemy/configuration/boolean_option.rb b/lib/alchemy/configuration/boolean_option.rb
new file mode 100644
index 0000000000..f68838c6b5
--- /dev/null
+++ b/lib/alchemy/configuration/boolean_option.rb
@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+
+require "alchemy/configuration/base_option"
+
+module Alchemy
+  class Configuration
+    class BooleanOption < BaseOption
+      private
+
+      def validate(value)
+        raise TypeError, "#{name} must be a Boolean, given #{value.inspect}" unless value.is_a?(TrueClass) || value.is_a?(FalseClass)
+        value
+      end
+    end
+  end
+end
diff --git a/lib/alchemy/configuration/class_option.rb b/lib/alchemy/configuration/class_option.rb
new file mode 100644
index 0000000000..f85d43de8b
--- /dev/null
+++ b/lib/alchemy/configuration/class_option.rb
@@ -0,0 +1,15 @@
+# frozen_string_literal: true
+
+require "alchemy/configuration/base_option"
+
+module Alchemy
+  class Configuration
+    class ClassOption < BaseOption
+      def self.value_class
+        String
+      end
+
+      def value = @value.constantize
+    end
+  end
+end
diff --git a/lib/alchemy/configuration/class_set_option.rb b/lib/alchemy/configuration/class_set_option.rb
new file mode 100644
index 0000000000..a3900d4398
--- /dev/null
+++ b/lib/alchemy/configuration/class_set_option.rb
@@ -0,0 +1,46 @@
+# frozen_string_literal: true
+
+require "alchemy/configuration/base_option"
+
+module Alchemy
+  class Configuration
+    class ClassSetOption < BaseOption
+      include Enumerable
+
+      def value = self
+
+      def <<(klass)
+        @value << klass.to_s
+      end
+
+      def concat(klasses)
+        klasses.each do |klass|
+          self << klass
+        end
+
+        self
+      end
+
+      delegate :clear, :empty?, to: :@value
+
+      def delete(object)
+        @value.delete(object.to_s)
+      end
+
+      def each
+        @value.each do |klass|
+          yield klass.constantize
+        end
+      end
+
+      def as_json = @value
+
+      private
+
+      def validate(value)
+        raise TypeError, "each #{name} must be set as a String" unless value.all? { _1.is_a?(String) }
+        value
+      end
+    end
+  end
+end
diff --git a/lib/alchemy/configuration/integer_list_option.rb b/lib/alchemy/configuration/integer_list_option.rb
new file mode 100644
index 0000000000..a22c06866d
--- /dev/null
+++ b/lib/alchemy/configuration/integer_list_option.rb
@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+require "alchemy/configuration/list_option"
+
+module Alchemy
+  class Configuration
+    class IntegerListOption < ListOption
+      def self.item_class
+        Integer
+      end
+    end
+  end
+end
diff --git a/lib/alchemy/configuration/integer_option.rb b/lib/alchemy/configuration/integer_option.rb
new file mode 100644
index 0000000000..937f4d9999
--- /dev/null
+++ b/lib/alchemy/configuration/integer_option.rb
@@ -0,0 +1,12 @@
+# frozen_string_literal: true
+
+require "alchemy/configuration/base_option"
+module Alchemy
+  class Configuration
+    class IntegerOption < BaseOption
+      def self.value_class
+        Integer
+      end
+    end
+  end
+end
diff --git a/lib/alchemy/configuration/list_option.rb b/lib/alchemy/configuration/list_option.rb
new file mode 100644
index 0000000000..c4a8b12954
--- /dev/null
+++ b/lib/alchemy/configuration/list_option.rb
@@ -0,0 +1,22 @@
+# frozen_string_literal: true
+
+require "alchemy/configuration/base_option"
+
+module Alchemy
+  class Configuration
+    class ListOption < BaseOption
+      def self.item_class
+        raise NotImplementedError
+      end
+
+      private
+
+      def validate(value)
+        unless value.is_a?(Array) && value.all? { _1.is_a?(self.class.item_class) }
+          raise TypeError, "#{@name} must be an Array of #{self.class.item_class.name.downcase.pluralize}, given #{value.inspect}"
+        end
+        value
+      end
+    end
+  end
+end
diff --git a/lib/alchemy/configuration/regexp_option.rb b/lib/alchemy/configuration/regexp_option.rb
new file mode 100644
index 0000000000..05fa61b132
--- /dev/null
+++ b/lib/alchemy/configuration/regexp_option.rb
@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+module Alchemy
+  class Configuration
+    class RegexpOption < BaseOption
+      def self.value_class
+        Regexp
+      end
+    end
+  end
+end
diff --git a/lib/alchemy/configuration/string_list_option.rb b/lib/alchemy/configuration/string_list_option.rb
new file mode 100644
index 0000000000..6da4832660
--- /dev/null
+++ b/lib/alchemy/configuration/string_list_option.rb
@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+require "alchemy/configuration/list_option"
+
+module Alchemy
+  class Configuration
+    class StringListOption < ListOption
+      def self.item_class
+        String
+      end
+    end
+  end
+end
diff --git a/lib/alchemy/configuration/string_option.rb b/lib/alchemy/configuration/string_option.rb
new file mode 100644
index 0000000000..0d3a44331f
--- /dev/null
+++ b/lib/alchemy/configuration/string_option.rb
@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+module Alchemy
+  class Configuration
+    class StringOption < BaseOption
+      def self.value_class
+        String
+      end
+    end
+  end
+end
diff --git a/lib/alchemy/configuration_methods.rb b/lib/alchemy/configuration_methods.rb
index f64f26d495..9b5c9b3ab4 100644
--- a/lib/alchemy/configuration_methods.rb
+++ b/lib/alchemy/configuration_methods.rb
@@ -13,7 +13,7 @@ module ConfigurationMethods
     # Config file is in +config/alchemy/config.yml+
     #
     def configuration(name)
-      Config.get(name)
+      Alchemy.config.get(name)
     end
 
     # Returns true if more than one language is published on current site.
diff --git a/lib/alchemy/configurations/default_language.rb b/lib/alchemy/configurations/default_language.rb
new file mode 100644
index 0000000000..c867a2295b
--- /dev/null
+++ b/lib/alchemy/configurations/default_language.rb
@@ -0,0 +1,12 @@
+# frozen_string_literal: true
+
+module Alchemy
+  module Configurations
+    class DefaultLanguage < Alchemy::Configuration
+      option :name, :string, default: "English"
+      option :code, :string, default: "en"
+      option :page_layout, :string, default: "index"
+      option :frontpage_name, :string, default: "Index"
+    end
+  end
+end
diff --git a/lib/alchemy/configurations/default_site.rb b/lib/alchemy/configurations/default_site.rb
new file mode 100644
index 0000000000..8539096e87
--- /dev/null
+++ b/lib/alchemy/configurations/default_site.rb
@@ -0,0 +1,10 @@
+# frozen_string_literal: true
+
+module Alchemy
+  module Configurations
+    class DefaultSite < Alchemy::Configuration
+      option :name, :string, default: "Default Site"
+      option :host, :string, default: "*"
+    end
+  end
+end
diff --git a/lib/alchemy/configurations/format_matchers.rb b/lib/alchemy/configurations/format_matchers.rb
new file mode 100644
index 0000000000..438b77d27d
--- /dev/null
+++ b/lib/alchemy/configurations/format_matchers.rb
@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+module Alchemy
+  module Configurations
+    class FormatMatchers < Alchemy::Configuration
+      option :email, :regexp, default: /\A[^@\s]+@([^@\s]+\.)+[^@\s]+\z/
+      option :url, :regexp, default: /\A[a-z0-9]+([\-\.]{1}[a-z0-9]+)*\.[a-z]{2,5}(:[0-9]{1,5})?(\/.*)?\z/ix
+      option :link_url, :regexp, default: /^(tel:|mailto:|\/|[a-z]+:\/\/)/
+    end
+  end
+end
diff --git a/lib/alchemy/configurations/mailer.rb b/lib/alchemy/configurations/mailer.rb
new file mode 100644
index 0000000000..05814d21dc
--- /dev/null
+++ b/lib/alchemy/configurations/mailer.rb
@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+
+module Alchemy
+  module Configurations
+    class Mailer < Alchemy::Configuration
+      option :page_layout_name, :string, default: "contact"
+      option :forward_to_page, :boolean, default: false
+      option :mail_success_page, :string, default: "thanks"
+      option :mail_from, :string, default: "your.mail@your-domain.com"
+      option :mail_to, :string, default: "your.mail@your-domain.com"
+      option :subject, :string, default: "A new contact form message"
+      option :fields, :string_list, default: %w[salutation firstname lastname address zip city phone email message]
+      option :validate_fields, :string_list, default: %w[lastname email]
+    end
+  end
+end
diff --git a/lib/alchemy/configurations/main.rb b/lib/alchemy/configurations/main.rb
new file mode 100644
index 0000000000..260def8d11
--- /dev/null
+++ b/lib/alchemy/configurations/main.rb
@@ -0,0 +1,199 @@
+# frozen_string_literal: true
+
+require "alchemy/configuration"
+require "alchemy/configurations/default_language"
+require "alchemy/configurations/default_site"
+require "alchemy/configurations/format_matchers"
+require "alchemy/configurations/mailer"
+require "alchemy/configurations/preview"
+require "alchemy/configurations/sitemap"
+require "alchemy/configurations/uploader"
+require "alchemy/deprecation"
+
+module Alchemy
+  module Configurations
+    class Main < Alchemy::Configuration
+      # == This is the global Alchemy configuration class
+
+      # === Auto Log Out Time
+      #
+      # The amount of time of inactivity in minutes after which the user is kicked out of his current session.
+      #
+      # NOTE: This is only active in production environments
+      #
+      option :auto_logout_time, :integer, default: 30
+
+      # === Page caching
+      #
+      # Enable/Disable page caching globally.
+      #
+      # NOTE: You can enable/disable page caching for single Alchemy::PageLayouts in the page_layout.yml file.
+      #
+      option :cache_pages, :boolean, default: true
+
+      # === Sitemap
+      #
+      # Alchemy creates a XML, Google compatible, sitemap for you.
+      #
+      # The url is: http://your-domain.tld/sitemap.xml
+      #
+      # ==== Config Options:
+      #
+      #   show_root [Boolean] # Show language root page in sitemap?
+      #   show_flag [Boolean] # Enables the Checkbox in Page#update overlay. So your customer can set the visibility of pages in the sitemap.
+      configuration :sitemap, Sitemap
+
+      # === Default items per page in admin views
+      #
+      # In Alchemy's Admin, change how many items you would get shown per page by Kaminari
+      option :items_per_page, :integer, default: 15
+
+      # === Preview window URL configuration
+      #
+      # By default Alchemy uses its internal page preview renderer,
+      # but you can configure it to be any URL instead.
+      #
+      # Basic Auth is supported.
+      #
+      # preview:
+      #   host: https://www.my-static-site.com
+      #   auth:
+      #     username: <%= ENV["BASIC_AUTH_USERNAME"] %>
+      #     password: <%= ENV["BASIC_AUTH_PASSWORD"] %>
+      #
+      # Preview config per site is supported as well.
+      #
+      # preview:
+      #   My site name:
+      #     host: https://www.my-static-site.com
+      #     auth:
+      #       username: <%= ENV["BASIC_AUTH_USERNAME"] %>
+      #       password: <%= ENV["BASIC_AUTH_PASSWORD"] %>
+      #
+      configuration :preview, Preview
+
+      # === Picture rendering settings
+      #
+      # Alchemy uses Dragonfly to render images. Settings for image rendering are specific to elements and are defined in elements.yml
+      #
+      # Example:
+      # - name: some_element
+      #   ingredients:
+      #   - role: some_picture
+      #     type: Picture
+      #     settings:
+      #       hint: true
+      #       crop: true  # turns on image cropping
+      #       size: '500x500' # image will be cropped to this size
+      #
+      # See http://markevans.github.com/dragonfly for further info.
+      #
+      # ==== Global Options:
+      #
+      #   output_image_quality      [Integer]       # If image gets rendered as JPG or WebP this is the quality setting for it. (Default 85)
+      #   preprocess_image_resize   [String]        # Use this option to resize images to the given size when they are uploaded to the image library. Downsizing example: '1000x1000>' (Default nil)
+      #   image_output_format       [String]        # The global image output format setting. (Default +original+)
+      #
+      # NOTE: You can always override the output format in the settings of your ingredients in elements.yml, I.E. {format: 'gif'}
+      #
+      option :output_image_quality, :integer, default: 85
+      alias_method :output_image_jpg_quality, :output_image_quality
+      deprecate output_image_jpg_quality: :output_image_quality, deprecator: Alchemy::Deprecation
+      alias_method :output_image_jpg_quality=, :output_image_quality=
+      deprecate "output_image_jpg_quality=": :output_image_quality=, deprecator: Alchemy::Deprecation
+      option :preprocess_image_resize, :string
+      option :image_output_format, :string, default: "original"
+
+      # This is used by the seeder to create the default site.
+      configuration :default_site, DefaultSite
+
+      # This is the default language when seeding.
+      configuration :default_language, DefaultLanguage
+
+      # === Mailer Settings:
+      #
+      # To send emails via contact forms, you can create your form fields here and set which fields are to be validated.
+      #
+      # === Validating fields:
+      #
+      # Pass the field name as a symbol and a message_id (will be translated) to :validate_fields:
+      #
+      # ==== Options:
+      #
+      #   page_layout_name:           [String] # A +Alchemy::PageLayout+ name. Used to render the contactform on a page with this layout.
+      #   fields:                     [Array]  # An Array of fieldnames.
+      #   validate_fields:            [Array]  # An Array of fieldnames to be validated on presence.
+      #
+      # ==== Translating validation messages:
+      #
+      # The validation messages are passed through ::I18n.t so you can translate it in your language yml file.
+      #
+      # ==== Example:
+      #
+      #   de:
+      #     activemodel:
+      #       attributes:
+      #         alchemy/message:
+      #           firstname: Vorname
+      #
+      configuration :mailer, Mailer
+
+      # === User roles
+      #
+      # You can add own user roles.
+      #
+      # Further documentation for the auth system used please visit:
+      #
+      # https://github.com/ryanb/cancan/wiki
+      #
+      # ==== Translating User roles
+      #
+      # Userroles can be translated inside your the language yml file under:
+      #
+      #   alchemy:
+      #     user_roles:
+      #       rolename: Name of the role
+      #
+      option :user_roles, :string_list, default: %w[member author editor admin]
+
+      # === Uploader Settings
+      #
+      #   upload_limit       [Integer]    # Set an amount of files upload limit of files which can be uploaded at once. Set 0 for unlimited.
+      #   file_size_limit*   [Integer]    # Set a file size limit in mega bytes for a per file limit.
+      #
+      # *) Allow filetypes to upload. Pass * to allow all kind of files.
+      #
+      configuration :uploader, Uploader
+
+      # === Link Target Options
+      #
+      # Values for the link target selectbox inside the page link overlay.
+      # The value gets attached as a data-link-target attribute to the link.
+      #
+      # == Example:
+      #
+      # Open all links set to overlay inside an jQuery UI Dialog Window.
+      #
+      #   jQuery(a[data-link-target="overlay"]).dialog();
+      #
+      option :link_target_options, :string_list, default: %w[blank]
+
+      # === Format matchers
+      #
+      # Named aliases for regular expressions that can be used in various places.
+      # The most common use case is the format validation of ingredients, or attribute validations of your individual models.
+      #
+      # == Example:
+      #
+      #   validates_format_of :url, with: Alchemy.config.get('format_matchers')['url']
+      #
+      configuration :format_matchers, FormatMatchers
+
+      # The layout used for rendering the +alchemy/admin/pages#show+ action.
+      option :admin_page_preview_layout, :string, default: "application"
+
+      # The sizes for the preview size select in the page editor.
+      option :page_preview_sizes, :integer_list, default: [360, 640, 768, 1024, 1280, 1440]
+    end
+  end
+end
diff --git a/lib/alchemy/configurations/preview.rb b/lib/alchemy/configurations/preview.rb
new file mode 100644
index 0000000000..4aacd92850
--- /dev/null
+++ b/lib/alchemy/configurations/preview.rb
@@ -0,0 +1,32 @@
+# frozen_string_literal: true
+
+module Alchemy
+  module Configurations
+    class Preview < Alchemy::Configuration
+      class PreviewAuth < Alchemy::Configuration
+        option :username, :string
+        option :password, :string
+      end
+
+      attr_reader :per_site_configs
+
+      def initialize(configuration = {})
+        @per_site_configs = []
+        configuration = configuration.with_indifferent_access
+        configuration.except(:host, :site_name, :auth).keys.each do |site_name|
+          @per_site_configs << Preview.new(configuration[site_name].merge(site_name: site_name))
+        end
+        super(configuration.slice(:host, :site_name, :auth))
+      end
+
+      option :site_name, :string, default: "*"
+      option :host, :string
+
+      configuration :auth, PreviewAuth
+
+      def for_site(site)
+        per_site_configs.detect { _1.site_name == site.name } || self
+      end
+    end
+  end
+end
diff --git a/lib/alchemy/configurations/sitemap.rb b/lib/alchemy/configurations/sitemap.rb
new file mode 100644
index 0000000000..cbee82252d
--- /dev/null
+++ b/lib/alchemy/configurations/sitemap.rb
@@ -0,0 +1,10 @@
+# frozen_string_literal: true
+
+module Alchemy
+  module Configurations
+    class Sitemap < Alchemy::Configuration
+      option :show_root, :boolean, default: true
+      option :show_flag, :boolean, default: false
+    end
+  end
+end
diff --git a/lib/alchemy/configurations/uploader.rb b/lib/alchemy/configurations/uploader.rb
new file mode 100644
index 0000000000..a96d7d96b0
--- /dev/null
+++ b/lib/alchemy/configurations/uploader.rb
@@ -0,0 +1,34 @@
+# frozen_string_literal: true
+
+module Alchemy
+  module Configurations
+    class Uploader < Alchemy::Configuration
+      class AllowedFileTypes < Alchemy::Configuration
+        option :alchemy_attachments, :string_list, default: ["*"]
+        option :alchemy_pictures, :string_list, default: %w[jpg jpeg gif png svg webp]
+
+        def set(configuration_hash)
+          super(configuration_hash.transform_keys { transform_key(_1) })
+        end
+
+        def get(key)
+          super(transform_key(key))
+        end
+        alias_method :[], :get
+
+        private
+
+        def transform_key(key)
+          key.to_s.tr("/", "_")
+        end
+      end
+
+      # Number of files that can be uploaded at once
+      option :upload_limit, :integer, default: 50
+      # Megabytes
+      option :file_size_limit, :integer, default: 100
+
+      configuration :allowed_filetypes, AllowedFileTypes
+    end
+  end
+end
diff --git a/lib/alchemy/engine.rb b/lib/alchemy/engine.rb
index bc9ec3a537..305f4dcf55 100644
--- a/lib/alchemy/engine.rb
+++ b/lib/alchemy/engine.rb
@@ -97,6 +97,18 @@ class Engine < Rails::Engine
       end
     end
 
+    initializer "alchemy.config_yml" do |app|
+      config_directory = Rails.root.join("config", "alchemy")
+      main_config = config_directory.join("config.yml")
+      env_specific_config = config_directory.join("#{Rails.env}.config.yml")
+      if File.exist?(main_config)
+        Alchemy.config.set_from_yaml(main_config)
+      end
+      if File.exist?(env_specific_config)
+        Alchemy.config.set_from_yaml(env_specific_config)
+      end
+    end
+
     config.after_initialize do
       if Alchemy.user_class
         ActiveSupport.on_load(:active_record) do
diff --git a/lib/alchemy/seeder.rb b/lib/alchemy/seeder.rb
index fa9e8828c6..adb93454ea 100644
--- a/lib/alchemy/seeder.rb
+++ b/lib/alchemy/seeder.rb
@@ -116,7 +116,7 @@ def create_page(draft, attributes = {})
       # If no languages are present, create a default language based
       # on the host app's Alchemy configuration.
       def create_default_language!
-        default_language = Alchemy::Config.get(:default_language)
+        default_language = Alchemy.config.get(:default_language)
         if default_language
           Alchemy::Language.create!(
             name: default_language["name"],
@@ -134,7 +134,7 @@ def create_default_language!
       end
 
       def create_default_site!
-        default_site = Alchemy::Config.get(:default_site)
+        default_site = Alchemy.config.get(:default_site)
         if default_site
           Alchemy::Site.create!(name: default_site["name"], host: default_site["host"])
         else
diff --git a/lib/alchemy/test_support/config_stubbing.rb b/lib/alchemy/test_support/config_stubbing.rb
index 1057a80282..a00e62f5df 100644
--- a/lib/alchemy/test_support/config_stubbing.rb
+++ b/lib/alchemy/test_support/config_stubbing.rb
@@ -17,13 +17,7 @@ module ConfigStubbing
       # @param value [Object] The value you want to return instead of the original one
       #
       def stub_alchemy_config(key, value)
-        allow(Alchemy::Config).to receive(:get) do |arg|
-          if arg == key
-            value
-          else
-            Alchemy::Config.show[arg.to_s]
-          end
-        end
+        allow(Alchemy.config).to receive(key).and_return(value)
       end
     end
   end
diff --git a/lib/alchemy/test_support/factories/language_factory.rb b/lib/alchemy/test_support/factories/language_factory.rb
index a26fb5a830..85d0008d34 100644
--- a/lib/alchemy/test_support/factories/language_factory.rb
+++ b/lib/alchemy/test_support/factories/language_factory.rb
@@ -6,7 +6,7 @@
     code { ::I18n.available_locales.first.to_s }
     default { true }
     frontpage_name { "Intro" }
-    page_layout { Alchemy::Config.get(:default_language)["page_layout"] }
+    page_layout { Alchemy.config.get(:default_language)["page_layout"] }
 
     public { true }
 
diff --git a/lib/alchemy/test_support/factories/site_factory.rb b/lib/alchemy/test_support/factories/site_factory.rb
index de5cb539fe..1cab21042a 100644
--- a/lib/alchemy/test_support/factories/site_factory.rb
+++ b/lib/alchemy/test_support/factories/site_factory.rb
@@ -8,8 +8,8 @@
     trait :default do
       public { true }
 
-      name { Alchemy::Config.get(:default_site)["name"] }
-      host { Alchemy::Config.get(:default_site)["host"] }
+      name { Alchemy.config.get(:default_site)["name"] }
+      host { Alchemy.config.get(:default_site)["host"] }
     end
 
     trait :public do
diff --git a/lib/alchemy/upgrader.rb b/lib/alchemy/upgrader.rb
index a17d387caa..65df0e405b 100644
--- a/lib/alchemy/upgrader.rb
+++ b/lib/alchemy/upgrader.rb
@@ -7,24 +7,5 @@ class Upgrader
     extend Alchemy::Shell
 
     Dir["#{File.dirname(__FILE__)}/upgrader/*.rb"].sort.each { |f| require f }
-
-    class << self
-      def copy_new_config_file
-        desc "Copy configuration file."
-        config_file = Rails.root.join("config/alchemy/config.yml")
-        default_config = File.join(File.dirname(__FILE__), "../../config/alchemy/config.yml")
-        if !File.exist? config_file
-          log "No configuration file found. Creating it."
-          FileUtils.cp default_config, Rails.root.join("config/alchemy/config.yml")
-        elsif FileUtils.identical? default_config, config_file
-          log "Configuration file already present.", :skip
-        else
-          log "Custom configuration file found."
-          FileUtils.cp default_config, Rails.root.join("config/alchemy/config.yml.defaults")
-          log "Copied new default configuration file."
-          todo "Check the default configuration file (./config/alchemy/config.yml.defaults) for new configuration options and insert them into your config file.", "Configuration has changed"
-        end
-      end
-    end
   end
 end
diff --git a/lib/alchemy_cms.rb b/lib/alchemy_cms.rb
index 89a56fa9de..861d8dfe04 100644
--- a/lib/alchemy_cms.rb
+++ b/lib/alchemy_cms.rb
@@ -25,7 +25,6 @@
 require_relative "alchemy/admin/preview_url"
 require_relative "alchemy/auth_accessors"
 require_relative "alchemy/cache_digests/template_tracker"
-require_relative "alchemy/config"
 require_relative "alchemy/configuration_methods"
 require_relative "alchemy/controller_actions"
 require_relative "alchemy/deprecation"
diff --git a/lib/generators/alchemy/install/install_generator.rb b/lib/generators/alchemy/install/install_generator.rb
index 4f18d252cb..5ea4658b7f 100644
--- a/lib/generators/alchemy/install/install_generator.rb
+++ b/lib/generators/alchemy/install/install_generator.rb
@@ -53,16 +53,16 @@ def mount
         install_tasks.inject_routes(options[:auto_accept])
       end
 
-      def copy_config
-        copy_file "#{gem_config_path}/config.yml", app_config_path.join("alchemy", "config.yml")
-      end
-
       def copy_yml_files
         %w[elements page_layouts menus].each do |file|
           template "#{__dir__}/templates/#{file}.yml.tt", app_config_path.join("alchemy", "#{file}.yml")
         end
       end
 
+      def copy_config_rb
+        template "#{__dir__}/templates/alchemy.rb.tt", app_config_path.join("initializers", "alchemy.rb")
+      end
+
       def install_assets
         copy_file "custom.css", app_assets_path.join("stylesheets/alchemy/admin/custom.css")
       end
diff --git a/lib/generators/alchemy/install/templates/alchemy.rb.tt b/lib/generators/alchemy/install/templates/alchemy.rb.tt
new file mode 100644
index 0000000000..224c98ff34
--- /dev/null
+++ b/lib/generators/alchemy/install/templates/alchemy.rb.tt
@@ -0,0 +1,197 @@
+Alchemy.configure do |config|
+  <% default_config = Alchemy::Configurations::Main.new %>
+  # == This is the global Alchemy configuration file
+  #
+
+  # === Auto Log Out Time
+  #
+  # The amount of time of inactivity in minutes after which the user is kicked out of his current session.
+  #
+  # NOTE: This is only active in production environments
+  #
+  # config.auto_logout_time = <%= default_config.auto_logout_time.inspect %>
+
+  # === Page caching
+  #
+  # Enable/Disable page caching globally.
+  #
+  # NOTE: You can enable/disable page caching for single Alchemy::PageLayouts in the page_layout.yml file.
+  #
+  # config.cache_pages = <%= default_config.cache_pages.inspect %>
+
+  # === Sitemap
+  #
+  # Alchemy creates a XML, Google compatible, sitemap for you.
+  #
+  # The url is: http://your-domain.tld/sitemap.xml
+  #
+  # ==== Config Options:
+  #
+  #   show_root [Boolean] # Show language root page in sitemap?
+  #   show_flag [Boolean] # Enables the Checkbox in Page#update overlay. So your customer can set the visibility of pages in the sitemap.
+  #
+  # config.sitemap.tap do |sitemap|
+  #   sitemap.show_root = <%= default_config.sitemap.show_root.inspect %>
+  #   sitemap.show_flag = <%= default_config.sitemap.show_flag.inspect %>
+  # end
+
+  # === Default items per page in admin views
+  #
+  # In Alchemy's Admin, change how many items you would get shown per page by Kaminari
+  # config.items_per_page = <%= default_config.items_per_page %>
+
+  # === Preview window URL configuration
+  #
+  # By default Alchemy uses its internal page preview renderer,
+  # but you can configure it to be any URL instead.
+  #
+  # Basic Auth is supported.
+  #
+  # config.preview = {
+  #   host: https://www.my-static-site.com
+  #   auth:
+  #     username: <%%= ENV["BASIC_AUTH_USERNAME"] %%>
+  #     password: <%%= ENV["BASIC_AUTH_PASSWORD"] %%>
+  # }
+  # Preview config per site is supported as well.
+  #
+  # config.preview = {
+  #   My site name:
+  #     host: https://www.my-static-site.com
+  #     auth:
+  #       username: <%%= ENV["BASIC_AUTH_USERNAME"] %%>
+  #       password: <%%= ENV["BASIC_AUTH_PASSWORD"] %%>
+  # }
+
+  # === Picture rendering settings
+  #
+  # Alchemy uses Dragonfly to render images. Settings for image rendering are specific to elements and are defined in elements.yml
+  #
+  # Example:
+  # - name: some_element
+  #   ingredients:
+  #   - role: some_picture
+  #     type: Picture
+  #     settings:
+  #       hint: true
+  #       crop: true  # turns on image cropping
+  #       size: '500x500' # image will be cropped to this size
+  #
+  # See http://markevans.github.com/dragonfly for further info.
+  #
+  # ==== Global Options:
+  #
+  #   output_image_quality      [Integer]       # If image gets rendered as JPG or WebP this is the quality setting for it. (Default 85)
+  #   preprocess_image_resize   [String]        # Use this option to resize images to the given size when they are uploaded to the image library. Downsizing example: '1000x1000>' (Default nil)
+  #   image_output_format       [String]        # The global image output format setting. (Default +original+)
+  #
+  # NOTE: You can always override the output format in the settings of your ingredients in elements.yml, I.E. {format: 'gif'}
+  #
+  # config.output_image_quality = <%= default_config.output_image_quality %>
+  # config.preprocess_image_resize = <%= default_config.preprocess_image_resize.inspect %>
+  # config.image_output_format = <%= default_config.image_output_format.inspect %>
+
+  # This is used by the seeder to create the default site.
+  # config.default_site.tap do |default_site|
+  #   default_site.name = <%= default_config.default_site.name.inspect %>
+  #   default_site.host = <%= default_config.default_site.host.inspect %>
+  # end
+
+  # This is the default language when seeding.
+  # config.default_language.tap do |default_language|
+  #   default_language.code = <%= default_config.default_language.code.inspect %>
+  #   default_language.name = <%= default_config.default_language.name.inspect %>
+  #   default_language.page_layout = <%= default_config.default_language.page_layout.inspect %>
+  #   default_language.frontpage_name = <%= default_config.default_language.frontpage_name.inspect %>
+  # end
+
+  # === Mailer Settings:
+  #
+  # To send emails via contact forms, you can create your form fields here and set which fields are to be validated.
+  #
+  # === Validating fields:
+  #
+  # Pass the field name as a symbol and a message_id (will be translated) to :validate_fields:
+  #
+  # ==== Options:
+  #
+  #   page_layout_name:           [String] # A +Alchemy::PageLayout+ name. Used to render the contactform on a page with this layout.
+  #   fields:                     [Array]  # An Array of fieldnames.
+  #   validate_fields:            [Array]  # An Array of fieldnames to be validated on presence.
+  #
+  # ==== Translating validation messages:
+  #
+  # The validation messages are passed through ::I18n.t so you can translate it in your language yml file.
+  #
+  # ==== Example:
+  #
+  #   de:
+  #     activemodel:
+  #       attributes:
+  #         alchemy/message:
+  #           firstname: Vorname
+  #
+  # config.mailer.tap do |mailer|
+  #   mailer.page_layout_name = <%= default_config.mailer.page_layout_name.inspect %>
+  #   mailer.forward_to_page = <%= default_config.mailer.forward_to_page.inspect %>
+  #   mailer.mail_success_page = <%= default_config.mailer.mail_success_page.inspect %>
+  #   mailer.mail_from = <%= default_config.mailer.mail_from.inspect %>
+  #   mailer.mail_to = <%= default_config.mailer.mail_to.inspect %>
+  #   mailer.subject = <%= default_config.mailer.subject.inspect %>
+  #   mailer.fields = <%= default_config.mailer.fields.inspect %>
+  #   mailer.validate_fields = <%= default_config.mailer.validate_fields.inspect %>
+  # end
+
+  # === User roles
+  #
+  # You can add own user roles.
+  #
+  # Further documentation for the auth system used please visit:
+  #
+  # https://github.com/ryanb/cancan/wiki
+  #
+  # ==== Translating User roles
+  #
+  # Userroles can be translated inside your the language yml file under:
+  #
+  #   alchemy:
+  #     user_roles:
+  #       rolename: Name of the role
+  #
+  # config.user_roles = <%= default_config.user_roles.inspect %>
+
+  # === Uploader Settings
+  #
+  #   upload_limit       [Integer]    # Set an amount of files upload limit of files which can be uploaded at once. Set 0 for unlimited.
+  #   file_size_limit*   [Integer]    # Set a file size limit in mega bytes for a per file limit.
+  #
+  # *) Allow filetypes to upload. Pass * to allow all kind of files.
+  #
+  # config.uploader.tap do |uploader|
+  #   uploader.upload_limit = <%= default_config.uploader.upload_limit.inspect %>
+  #   uploader.file_size_limit = <%= default_config.uploader.file_size_limit.inspect %>
+  #   uploader.allowed_filetypes.tap do |file_types|
+  #     file_types.alchemy_attachments = <%= default_config.uploader.allowed_filetypes.alchemy_attachments.inspect %>
+  #     file_types.alchemy_pictures = <%= default_config.uploader.allowed_filetypes.alchemy_pictures.inspect %>
+  #   end
+  # end
+
+  # === Link Target Options
+  #
+  # Values for the link target selectbox inside the page link overlay.
+  # The value gets attached as a data-link-target attribute to the link.
+  #
+  # == Example:
+  #
+  # Open all links set to overlay inside an jQuery UI Dialog Window.
+  #
+  #   jQuery(a[data-link-target="overlay"]).dialog();
+  #
+  # config.link_target_options = <%= default_config.link_target_options.inspect %>
+
+  # The layout used for rendering the +alchemy/admin/pages#show+ action.
+  # config.admin_page_preview_layout = <%= default_config.admin_page_preview_layout.inspect %>
+
+  # The sizes for the preview size select in the page editor.
+  # config.page_preview_sizes = <%= default_config.page_preview_sizes.inspect %>
+end
diff --git a/lib/generators/alchemy/install/templates/page_layouts.yml.tt b/lib/generators/alchemy/install/templates/page_layouts.yml.tt
index 45a73a3907..cf727885ca 100644
--- a/lib/generators/alchemy/install/templates/page_layouts.yml.tt
+++ b/lib/generators/alchemy/install/templates/page_layouts.yml.tt
@@ -3,7 +3,7 @@
 # For further information please see https://guides.alchemy-cms.com/pages.html
 
 <%- unless @options[:skip_demo_files] -%>
-- name: <%= Alchemy::Config.get(:default_language)['page_layout'] %>
+- name: <%= Alchemy.config.get(:default_language)['page_layout'] %>
   unique: true
   elements: [article]
   autogenerate: [article]
diff --git a/lib/tasks/alchemy/upgrade.rake b/lib/tasks/alchemy/upgrade.rake
index de7fa571fc..c9f971a5d1 100644
--- a/lib/tasks/alchemy/upgrade.rake
+++ b/lib/tasks/alchemy/upgrade.rake
@@ -23,10 +23,5 @@ namespace :alchemy do
       "alchemy:install:migrations",
       "db:migrate"
     ]
-
-    desc "Alchemy Upgrader: Copy configuration file."
-    task config: [:environment] do
-      Alchemy::Upgrader.copy_new_config_file
-    end
   end
 end
diff --git a/spec/controllers/alchemy/admin/languages_controller_spec.rb b/spec/controllers/alchemy/admin/languages_controller_spec.rb
index 7892287e32..9b43456d48 100644
--- a/spec/controllers/alchemy/admin/languages_controller_spec.rb
+++ b/spec/controllers/alchemy/admin/languages_controller_spec.rb
@@ -65,7 +65,7 @@
       it "has default language's page_layout set" do
         get :new
         expect(assigns(:language).page_layout)
-          .to eq(Alchemy::Config.get(:default_language)["page_layout"])
+          .to eq(Alchemy.config.get(:default_language)["page_layout"])
       end
     end
   end
diff --git a/spec/controllers/alchemy/base_controller_spec.rb b/spec/controllers/alchemy/base_controller_spec.rb
index 505b1c01a4..6175a73cc0 100644
--- a/spec/controllers/alchemy/base_controller_spec.rb
+++ b/spec/controllers/alchemy/base_controller_spec.rb
@@ -29,7 +29,7 @@ module Alchemy
 
     describe "#configuration" do
       it "returns certain configuration options" do
-        allow(Config).to receive(:show).and_return({"some_option" => true})
+        allow(Config).to receive(:some_option).and_return(true)
         expect(controller.configuration(:some_option)).to eq(true)
       end
     end
diff --git a/spec/controllers/alchemy/messages_controller_spec.rb b/spec/controllers/alchemy/messages_controller_spec.rb
index 26aa25004c..e996c1664b 100644
--- a/spec/controllers/alchemy/messages_controller_spec.rb
+++ b/spec/controllers/alchemy/messages_controller_spec.rb
@@ -265,7 +265,7 @@ module Alchemy
 
       context "when mailer_config['fields'] does not inlcude :contact_field_id" do
         it "should permit :contact_form_id" do
-          expect(Alchemy::Config.get(:mailer)["fields"]).not_to include "contact_field_id"
+          expect(Alchemy.config.get(:mailer)["fields"]).not_to include "contact_field_id"
           msg_params = subject.send(:message_params)
 
           expect(msg_params).to include :contact_form_id
diff --git a/spec/dummy/config/alchemy/config.yml b/spec/dummy/config/alchemy/config.yml
new file mode 100644
index 0000000000..7c38b87918
--- /dev/null
+++ b/spec/dummy/config/alchemy/config.yml
@@ -0,0 +1,2 @@
+output_image_quality: 90
+auto_logout_time: 40
diff --git a/spec/dummy/config/alchemy/elements.yml b/spec/dummy/config/alchemy/elements.yml
index 22c5455f42..c7e7045390 100644
--- a/spec/dummy/config/alchemy/elements.yml
+++ b/spec/dummy/config/alchemy/elements.yml
@@ -67,7 +67,7 @@
     - role: mail_from
       type: Text
       validate:
-        - presence
+        - format: email
     - role: mail_to
       type: Text
       validate:
diff --git a/spec/dummy/config/alchemy/test.config.yml b/spec/dummy/config/alchemy/test.config.yml
new file mode 100644
index 0000000000..6dab462ebd
--- /dev/null
+++ b/spec/dummy/config/alchemy/test.config.yml
@@ -0,0 +1 @@
+output_image_quality: 85
diff --git a/spec/fixtures/config.yml b/spec/fixtures/config.yml
new file mode 100644
index 0000000000..4e828e9742
--- /dev/null
+++ b/spec/fixtures/config.yml
@@ -0,0 +1 @@
+auto_logout_time: 20
diff --git a/spec/libraries/admin/preview_url_spec.rb b/spec/libraries/admin/preview_url_spec.rb
index 2d68e10bd8..3d7b9f8636 100644
--- a/spec/libraries/admin/preview_url_spec.rb
+++ b/spec/libraries/admin/preview_url_spec.rb
@@ -21,9 +21,9 @@
     context "with preview configured" do
       context "without protocol" do
         before do
-          stub_alchemy_config(:preview, {
+          stub_alchemy_config(:preview, Alchemy::Configurations::Preview.new({
             "host" => "www.example.com"
-          })
+          }))
         end
 
         it "raises error" do
@@ -33,9 +33,9 @@
 
       context "as http url" do
         before do
-          stub_alchemy_config(:preview, {
+          stub_alchemy_config(:preview, Alchemy::Configurations::Preview.new({
             "host" => "http://www.example.com"
-          })
+          }))
         end
 
         it "returns the configured preview url" do
@@ -45,9 +45,9 @@
 
       context "as https url" do
         before do
-          stub_alchemy_config(:preview, {
+          stub_alchemy_config(:preview, Alchemy::Configurations::Preview.new({
             "host" => "https://www.example.com"
-          })
+          }))
         end
 
         it "returns the configured preview url with https" do
@@ -57,13 +57,13 @@
 
       context "and with basic auth configured" do
         before do
-          stub_alchemy_config(:preview, {
+          stub_alchemy_config(:preview, Alchemy::Configurations::Preview.new({
             "host" => "https://www.example.com",
             "auth" => {
               "username" => "foo",
               "password" => "baz"
             }
-          })
+          }))
         end
 
         it "returns the configured preview url with userinfo" do
@@ -73,9 +73,9 @@
 
       context "with a port configured" do
         before do
-          stub_alchemy_config(:preview, {
+          stub_alchemy_config(:preview, Alchemy::Configurations::Preview.new({
             "host" => "https://www.example.com:8080"
-          })
+          }))
         end
 
         it "returns the configured preview url with userinfo" do
@@ -90,11 +90,11 @@
 
         context "that matches the pages site name" do
           let(:config) do
-            {
+            Alchemy::Configurations::Preview.new({
               page.site.name => {
                 "host" => "http://new.example.com"
               }
-            }
+            })
           end
 
           it "returns the configured preview url for that site" do
@@ -105,12 +105,12 @@
         context "that does not match the pages site name" do
           context "with a default configured" do
             let(:config) do
-              {
+              Alchemy::Configurations::Preview.new({
                 "Not matching site name" => {
                   "host" => "http://new.example.com"
                 },
                 "host" => "http://www.example.com"
-              }
+              })
             end
 
             it "returns the default configured preview url" do
@@ -120,11 +120,11 @@
 
           context "without a default configured" do
             let(:config) do
-              {
+              Alchemy::Configurations::Preview.new({
                 "Not matching site name" => {
                   "host" => "http://new.example.com"
                 }
-              }
+              })
             end
 
             it "returns the internal preview url" do
@@ -138,9 +138,9 @@
         let(:page) { create(:alchemy_page, :language_root) }
 
         before do
-          stub_alchemy_config(:preview, {
+          stub_alchemy_config(:preview, Alchemy::Configurations::Preview.new({
             "host" => "https://www.example.com"
-          })
+          }))
         end
 
         it "returns the preview url without urlname" do
diff --git a/spec/libraries/alchemy/configuration/class_set_option_spec.rb b/spec/libraries/alchemy/configuration/class_set_option_spec.rb
new file mode 100644
index 0000000000..bb2473ea6c
--- /dev/null
+++ b/spec/libraries/alchemy/configuration/class_set_option_spec.rb
@@ -0,0 +1,99 @@
+# frozen_string_literal: true
+
+require "rails_helper"
+require "alchemy/configuration/class_set_option"
+
+module ClassSetTest
+  ClassA = Class.new
+  ClassB = Class.new
+
+  def self.reload
+    [:ClassA, :ClassB].each do |klass|
+      remove_const(klass)
+      const_set(klass, Class.new)
+    end
+  end
+end
+
+RSpec.describe Alchemy::Configuration::ClassSetOption do
+  let(:set) { described_class.new(value: [], name: :my_class_set) }
+
+  describe "#concat" do
+    it "can add one item" do
+      set.concat(["ClassSetTest::ClassA"])
+      expect(set).to include(ClassSetTest::ClassA)
+    end
+
+    it "can add two items" do
+      set.concat(["ClassSetTest::ClassA", ClassSetTest::ClassB])
+      expect(set).to include(ClassSetTest::ClassA)
+      expect(set).to include(ClassSetTest::ClassB)
+    end
+
+    it "returns itself" do
+      expect(set.concat(["String"])).to eql(set)
+    end
+  end
+
+  describe "initializing with a default" do
+    let(:set) { described_class.new(value: ["ClassSetTest::ClassA"], name: :my_class_set) }
+
+    it "contains the default" do
+      expect(set).to include(ClassSetTest::ClassA)
+    end
+  end
+
+  describe "<<" do
+    it "can add by string" do
+      set << "ClassSetTest::ClassA"
+      expect(set).to include(ClassSetTest::ClassA)
+    end
+
+    it "can add by class" do
+      set << ClassSetTest::ClassA
+      expect(set).to include(ClassSetTest::ClassA)
+    end
+
+    describe "class redefinition" do
+      shared_examples "working code reloading" do
+        it "works with a class" do
+          original = ClassSetTest::ClassA
+
+          ClassSetTest.reload
+
+          # Sanity check
+          expect(original).not_to eq(ClassSetTest::ClassA)
+
+          expect(set).to include(ClassSetTest::ClassA)
+          expect(set).to_not include(original)
+        end
+      end
+
+      context "with a class" do
+        before { set << ClassSetTest::ClassA }
+        it_should_behave_like "working code reloading"
+      end
+
+      context "with a string" do
+        before { set << "ClassSetTest::ClassA" }
+        it_should_behave_like "working code reloading"
+      end
+    end
+  end
+
+  describe "#delete" do
+    before do
+      set << ClassSetTest::ClassA
+    end
+
+    it "can delete by string" do
+      set.delete "ClassSetTest::ClassA"
+      expect(set).not_to include(ClassSetTest::ClassA)
+    end
+
+    it "can delete by class" do
+      set.delete ClassSetTest::ClassA
+      expect(set).not_to include(ClassSetTest::ClassA)
+    end
+  end
+end
diff --git a/spec/libraries/alchemy/configuration/list_option_spec.rb b/spec/libraries/alchemy/configuration/list_option_spec.rb
new file mode 100644
index 0000000000..4cc81134be
--- /dev/null
+++ b/spec/libraries/alchemy/configuration/list_option_spec.rb
@@ -0,0 +1,14 @@
+# frozen_string_literal: true
+
+require "rails_helper"
+require "alchemy/configuration/list_option"
+
+RSpec.describe Alchemy::Configuration::ListOption do
+  describe ".item_class" do
+    subject { described_class.item_class }
+
+    it "raises NotImplementedError" do
+      expect { subject }.to raise_exception(NotImplementedError)
+    end
+  end
+end
diff --git a/spec/libraries/alchemy/configuration_spec.rb b/spec/libraries/alchemy/configuration_spec.rb
new file mode 100644
index 0000000000..0ccae5e33b
--- /dev/null
+++ b/spec/libraries/alchemy/configuration_spec.rb
@@ -0,0 +1,273 @@
+# frozen_string_literal: true
+
+require "rails_helper"
+require "alchemy/configuration"
+
+RSpec.describe Alchemy::Configuration do
+  let(:configuration) do
+    Class.new(described_class) do
+      option :auto_logout_time, :integer, default: 30
+    end.new
+  end
+
+  it "has a setter" do
+    expect do
+      configuration.auto_logout_time = 15
+    end.to change { configuration.auto_logout_time }.from(30).to(15)
+  end
+
+  it "allows setting the option to nil" do
+    expect do
+      configuration.auto_logout_time = nil
+    end.to change { configuration.auto_logout_time }.from(30).to(nil)
+  end
+
+  it "has several getters" do
+    expect(configuration["auto_logout_time"]).to eq(30)
+    expect(configuration.auto_logout_time).to eq(30)
+    expect(configuration.get(:auto_logout_time)).to eq(30)
+  end
+
+  it "returns self when #show is called" do
+    expect(configuration.show).to eq(configuration)
+  end
+
+  context "without a default value" do
+    let(:configuration) do
+      Class.new(described_class) do
+        option :auto_logout_time, :integer
+      end.new
+    end
+
+    it "defaults to nil" do
+      expect(configuration.auto_logout_time).to be nil
+    end
+
+    describe "#fetch" do
+      it "allows getting data but setting a default, like Hash" do
+        expect(configuration.fetch("auto_logout_time", 20)).to eq(20)
+        configuration.auto_logout_time = 40
+        expect(configuration.fetch("auto_logout_time", 20)).to eq(40)
+      end
+    end
+  end
+
+  context "setting with the wrong type" do
+    it "raises an error" do
+      expect do
+        configuration.auto_logout_time = "14"
+      end.to raise_exception(TypeError, 'auto_logout_time must be set as a Integer, given "14"')
+    end
+  end
+
+  describe "setting classes" do
+    let(:configuration) do
+      Class.new(described_class) do
+        option :picture_thumb_storage_class, :class, default: "Alchemy::PictureThumb::FileStore"
+      end.new
+    end
+
+    it "returns the constantized class" do
+      expect(configuration.picture_thumb_storage_class).to be Alchemy::PictureThumb::FileStore
+    end
+
+    it "can only be set using a string" do
+      expect do
+        configuration.picture_thumb_storage_class = String
+      end.to raise_exception(TypeError, "picture_thumb_storage_class must be set as a String, given String")
+    end
+  end
+
+  describe "setting and changing class sets" do
+    let(:configuration) do
+      Class.new(described_class) do
+        option :preview_sources, :class_set, default: ["Alchemy::Admin::PreviewUrl"]
+      end.new
+    end
+
+    it "returns an Enumerable that returns all classes as constants" do
+      expect(configuration.preview_sources.to_a).to eq([Alchemy::Admin::PreviewUrl])
+    end
+  end
+
+  describe "Boolean options" do
+    let(:configuration) do
+      Class.new(described_class) do
+        option :cache_pages, :boolean, default: true
+      end.new
+    end
+
+    it "returns the boolean" do
+      expect(configuration.cache_pages).to be true
+    end
+
+    it "can only be set with a Boolean" do
+      expect do
+        configuration.cache_pages = "true"
+      end.to raise_exception(TypeError, "cache_pages must be a Boolean, given \"true\"")
+    end
+  end
+
+  describe "integer lists" do
+    let(:configuration) do
+      Class.new(described_class) do
+        option :page_preview_sizes, :integer_list, default: [1, 2]
+      end.new
+    end
+
+    it "returns the integer list" do
+      expect(configuration.page_preview_sizes).to eq([1, 2])
+    end
+
+    it "can only be set with an integer list" do
+      expect do
+        configuration.page_preview_sizes = ["1"]
+      end.to raise_exception(TypeError, 'page_preview_sizes must be an Array of integers, given ["1"]')
+    end
+  end
+
+  describe "string lists" do
+    let(:configuration) do
+      Class.new(described_class) do
+        option :link_target_options, :string_list, default: ["blank"]
+      end.new
+    end
+
+    it "returns the string list" do
+      expect(configuration.link_target_options).to eq(["blank"])
+    end
+
+    it "can only be set with an Array of strings" do
+      expect do
+        configuration.link_target_options = [:blank]
+      end.to raise_exception(TypeError, "link_target_options must be an Array of strings, given [:blank]")
+    end
+  end
+
+  describe "string options" do
+    let(:configuration) do
+      Class.new(described_class) do
+        option :mail_success_page, :string, default: "thanks"
+      end.new
+    end
+
+    it "returns the string list" do
+      expect(configuration.mail_success_page).to eq("thanks")
+    end
+
+    it "can only be set with an Array of strings" do
+      expect do
+        configuration.mail_success_page = :thanks
+      end.to raise_exception(TypeError, "mail_success_page must be set as a String, given :thanks")
+    end
+  end
+
+  describe "regexp options" do
+    let(:configuration) do
+      Class.new(described_class) do
+        option :email, :regexp, default: /\A.*\z/
+      end.new
+    end
+
+    it "returns the regexp" do
+      expect(configuration.email).to eq(/\A.*\z/)
+    end
+
+    it "can only be set with a regexp" do
+      expect do
+        configuration.email = '/\A.*\z/'
+      end.to raise_exception(TypeError, /email must be set as a Regexp, given .*/)
+    end
+  end
+
+  describe "initializing with a hash" do
+    let(:configuration_class) do
+      Class.new(described_class) do
+        option :mail_success_page, :string, default: "thanks"
+        option :link_target_options, :string_list, default: ["blank"]
+      end
+    end
+
+    let(:configuration) do
+      configuration_class.new(mail_success_page: "verymuchthankyou", link_target_options: ["top"])
+    end
+
+    it "takes the values from the hash" do
+      expect(configuration.mail_success_page).to eq("verymuchthankyou")
+      expect(configuration.link_target_options).to eq(["top"])
+    end
+  end
+
+  describe "#set" do
+    let(:configuration_class) do
+      Class.new(described_class) do
+        option :mail_success_page, :string, default: "thanks"
+        option :link_target_options, :string_list, default: ["blank"]
+      end
+    end
+
+    let(:configuration) do
+      configuration_class.new
+    end
+
+    it "takes the values from the hash" do
+      configuration.set(mail_success_page: "verymuchthankyou", link_target_options: ["top"])
+      expect(configuration.mail_success_page).to eq("verymuchthankyou")
+      expect(configuration.link_target_options).to eq(["top"])
+    end
+  end
+
+  describe "get" do
+    let(:configuration) do
+      Class.new(described_class) do
+        option :mail_success_page, :string, default: "thanks"
+        option :link_target_options, :string_list, default: ["blank"]
+      end.new
+    end
+
+    subject { configuration.get(:mail_success_page) }
+
+    it { is_expected.to eq("thanks") }
+
+    it "can be converted to a Hash" do
+      expect(configuration.to_h).to eq(
+        mail_success_page: "thanks",
+        link_target_options: ["blank"]
+      )
+    end
+  end
+
+  describe "nested configurations" do
+    let(:configuration) do
+      uploader_configuration_class = Class.new(described_class) do
+        option :file_size_limit, :integer, default: 100
+        option :upload_limit, :integer, default: 50
+      end
+
+      Class.new(described_class) do
+        configuration :uploader, uploader_configuration_class
+      end.new
+    end
+
+    it "can be accessed as methods" do
+      expect(configuration.uploader.upload_limit).to eq(50)
+    end
+
+    it "can be accessed with []" do
+      expect(configuration[:uploader][:upload_limit]).to eq(50)
+    end
+
+    it "can be set using a nested hash" do
+      configuration.set(uploader: {upload_limit: 30})
+      configuration.set(uploader: {file_size_limit: 80})
+      expect(configuration.uploader.upload_limit).to eq(30)
+      expect(configuration.uploader.file_size_limit).to eq(80)
+    end
+
+    it "can be converted to a Hash" do
+      expect(configuration.to_h).to eq(
+        uploader: {file_size_limit: 100, upload_limit: 50}
+      )
+    end
+  end
+end
diff --git a/spec/libraries/alchemy/configurations/main_spec.rb b/spec/libraries/alchemy/configurations/main_spec.rb
new file mode 100644
index 0000000000..a2b1253a5f
--- /dev/null
+++ b/spec/libraries/alchemy/configurations/main_spec.rb
@@ -0,0 +1,36 @@
+# frozen_string_literal: true
+
+require "rails_helper"
+require "alchemy/configurations/main"
+
+RSpec.describe Alchemy::Configurations::Main do
+  describe "#set_from_yaml" do
+    let(:fixture_file) do
+      Rails.root.join("..", "fixtures", "config.yml")
+    end
+
+    subject { described_class.new }
+
+    before { subject.set_from_yaml(fixture_file) }
+
+    it "has data from the yaml file" do
+      expect(subject.auto_logout_time).to eq(20)
+    end
+  end
+
+  describe "deprecated: #output_image_jpg_quality getter" do
+    it "warns and tells us about the right method" do
+      expect(Alchemy::Deprecation).to receive(:warn).at_least(:once)
+      expect(subject.output_image_jpg_quality).to eq(85)
+    end
+  end
+
+  describe "deprecated: #output_image_jpg_quality setter" do
+    it "warns and tells us about the right method" do
+      expect(Alchemy::Deprecation).to receive(:warn).at_least(:once)
+      expect do
+        subject.output_image_jpg_quality = 90
+      end.to change { subject.output_image_quality }.from(85).to(90)
+    end
+  end
+end
diff --git a/spec/libraries/alchemy_spec.rb b/spec/libraries/alchemy_spec.rb
index ff3d2f6abb..ec8ced94a9 100644
--- a/spec/libraries/alchemy_spec.rb
+++ b/spec/libraries/alchemy_spec.rb
@@ -35,4 +35,78 @@
       end
     end
   end
+
+  describe ".config" do
+    subject { Alchemy.config }
+
+    it "is a config object" do
+      expect(subject).to be_a(Alchemy::Configurations::Main)
+    end
+
+    it "has the auto_logout_time from config.yml" do
+      expect(subject.auto_logout_time).to eq(40)
+    end
+
+    it "has the output_image_quality from test.config.yml" do
+      expect(subject.output_image_quality).to eq(85)
+    end
+
+    it "has the default image output format" do
+      expect(subject.image_output_format).to eq("original")
+    end
+
+    describe "format matchers" do
+      describe "email" do
+        subject { Alchemy.config.get("format_matchers")["email"] }
+
+        it { is_expected.to match("hello@gmail.com") }
+        it { is_expected.not_to match("stulli@gmx") }
+      end
+
+      describe "url" do
+        subject { Alchemy.config.get("format_matchers")["url"] }
+
+        it { is_expected.to match("www.example.com:80/about") }
+        it { is_expected.not_to match('www.example.com:80\/about') }
+      end
+
+      describe "link_url" do
+        subject { Alchemy.config.get("format_matchers")["link_url"] }
+
+        it { is_expected.to match("tel:12345") }
+        it { is_expected.to match("mailto:stulli@gmx.de") }
+        it { is_expected.to match("/home") }
+        it { is_expected.to match("https://example.com/home") }
+        it { is_expected.not_to match('\/brehmstierleben') }
+        it { is_expected.not_to match('https:\/\/example.com/home') }
+      end
+    end
+  end
+
+  describe ".configure" do
+    subject do
+      Alchemy.configure do |config|
+        config.auto_logout_time = 500
+      end
+    end
+
+    around do |example|
+      old_auto_logout_time = Alchemy.config.auto_logout_time
+      example.run
+      Alchemy.config.auto_logout_time = old_auto_logout_time
+    end
+
+    it "yields the config object" do
+      expect { subject }.to change(Alchemy.config, :auto_logout_time).to(500)
+    end
+  end
+
+  describe "deprecated: Config" do
+    subject { Alchemy::Config }
+
+    it "is the same as Alchemy.config, but deprecated" do
+      expect(Alchemy::Deprecation).to receive(:warn)
+      expect(Alchemy::Config).to eq(Alchemy.config)
+    end
+  end
 end
diff --git a/spec/libraries/config_spec.rb b/spec/libraries/config_spec.rb
deleted file mode 100644
index 45a03c37b2..0000000000
--- a/spec/libraries/config_spec.rb
+++ /dev/null
@@ -1,209 +0,0 @@
-# frozen_string_literal: true
-
-require "rails_helper"
-
-module Alchemy
-  describe Config do
-    describe ".get" do
-      it "should call #show" do
-        expect(Config).to receive(:show).and_return({})
-        Config.get(:mailer)
-      end
-
-      it "should return the requested part of the config" do
-        expect(Config).to receive(:show).and_return({"mailer" => {"setting" => "true"}})
-        expect(Config.get(:mailer)).to eq({"setting" => "true"})
-      end
-
-      context "if config is deprecated" do
-        context "without a new default" do
-          before do
-            expect(described_class).to receive(:deprecated_configs).at_least(:once) do
-              {foo: nil}
-            end
-          end
-
-          it "warns" do
-            expect(Alchemy::Deprecation).to receive(:warn)
-            Config.get(:foo)
-          end
-        end
-
-        context "with a new default" do
-          before do
-            expect(described_class).to receive(:deprecated_configs).at_least(:once) do
-              {foo: true}
-            end
-          end
-
-          context "and current value is not the default" do
-            before do
-              expect(described_class).to receive(:show).at_least(:once) do
-                {"foo" => false}
-              end
-            end
-
-            it "warns about new default" do
-              expect(Alchemy::Deprecation).to \
-                receive(:warn).with("Setting foo configuration to false is deprecated and will be always true in Alchemy #{Alchemy::Deprecation.deprecation_horizon}")
-              Config.get(:foo)
-            end
-          end
-        end
-      end
-
-      context "if config has been replaced" do
-        context "with a new default" do
-          before do
-            expect(described_class).to receive(:replaced_config_keys).at_least(:once) do
-              {foo: :bar}
-            end
-          end
-
-          context "and config uses old key" do
-            before do
-              expect(described_class).to receive(:show).at_least(:once) do
-                {"bar" => :baz}
-              end
-            end
-
-            it "warns about new key and returns old value" do
-              expect(Alchemy::Deprecation).to \
-                receive(:warn).with("Using bar configuration is deprecated and will be removed in Alchemy #{Alchemy::Deprecation.deprecation_horizon}. Please use foo instead.")
-              expect(Config.get(:foo)).to eq(:baz)
-            end
-          end
-
-          context "and config uses new key" do
-            before do
-              expect(described_class).to receive(:show).at_least(:once) do
-                {"foo" => :bar}
-              end
-            end
-
-            it "warns about new key and returns old value" do
-              expect(Alchemy::Deprecation).to_not receive(:warn)
-              expect(Config.get(:foo)).to eq(:bar)
-            end
-          end
-        end
-      end
-    end
-
-    describe ".main_app_config" do
-      let(:main_app_config_path) { Rails.root.join("config/alchemy/config.yml") }
-
-      it "should call and return .read_file with the correct config path" do
-        expect(Config).to receive(:read_file).with(main_app_config_path).once.and_return({setting: "true"})
-        expect(Config.send(:main_app_config)).to eq({setting: "true"})
-      end
-    end
-
-    describe ".env_specific_config" do
-      let(:env_specific_config_path) { Rails.root.join("config/alchemy/#{Rails.env}.config.yml") }
-
-      it "should call and return .read_file with the correct config path" do
-        expect(Config).to receive(:read_file).with(env_specific_config_path).once.and_return({setting: "true"})
-        expect(Config.send(:env_specific_config)).to eq({setting: "true"})
-      end
-    end
-
-    describe ".show" do
-      context "when ivar @config was not set before" do
-        before { Config.instance_variable_set(:@config, nil) }
-
-        it "should call and return .merge_configs!" do
-          expect(Config).to receive(:merge_configs!).once.and_return({setting: "true"})
-          expect(Config.show).to eq({setting: "true"})
-        end
-      end
-
-      context "when ivar @config was already set" do
-        before { Config.instance_variable_set(:@config, {setting: "true"}) }
-        after { Config.instance_variable_set(:@config, nil) }
-
-        it "should have memoized the return value of .merge_configs!" do
-          expect(Config.send(:show)).to eq({setting: "true"})
-        end
-      end
-    end
-
-    describe ".read_file" do
-      context "when given path to yml file exists" do
-        context "and file is empty" do
-          before do
-            # YAML.safe_load returns nil if file is empty.
-            allow(YAML).to receive(:safe_load) { nil }
-          end
-
-          it "should return an empty Hash" do
-            expect(Config.send(:read_file, "empty_file.yml")).to eq({})
-          end
-        end
-      end
-
-      context "when given path to yml file does not exist" do
-        it "should return an empty Hash" do
-          expect(Config.send(:read_file, "does/not/exist.yml")).to eq({})
-        end
-      end
-    end
-
-    describe ".merge_configs!" do
-      let(:config_1) do
-        {setting_1: "same", other_setting: "something"}
-      end
-
-      let(:config_2) do
-        {setting_1: "same", setting_2: "anything"}
-      end
-
-      it "should stringify the keys" do
-        expect(Config.send(:merge_configs!, config_1)).to eq(config_1.stringify_keys!)
-      end
-
-      context "when all passed configs are empty" do
-        it "should raise an error" do
-          expect { Config.send(:merge_configs!, {}) }.to raise_error(LoadError)
-        end
-      end
-
-      context "when configs containing same keys" do
-        it "should merge them together" do
-          expect(Config.send(:merge_configs!, config_1, config_2)).to eq(
-            "setting_1" => "same",
-            "other_setting" => "something",
-            "setting_2" => "anything"
-          )
-        end
-      end
-    end
-
-    describe "format matchers" do
-      describe "email" do
-        subject { Alchemy::Config.get("format_matchers")["email"] }
-
-        it { is_expected.to match("hello@gmail.com") }
-        it { is_expected.not_to match("stulli@gmx") }
-      end
-
-      describe "url" do
-        subject { Alchemy::Config.get("format_matchers")["url"] }
-
-        it { is_expected.to match("www.example.com:80/about") }
-        it { is_expected.not_to match('www.example.com:80\/about') }
-      end
-
-      describe "link_url" do
-        subject { Alchemy::Config.get("format_matchers")["link_url"] }
-
-        it { is_expected.to match("tel:12345") }
-        it { is_expected.to match("mailto:stulli@gmx.de") }
-        it { is_expected.to match("/home") }
-        it { is_expected.to match("https://example.com/home") }
-        it { is_expected.not_to match('\/brehmstierleben') }
-        it { is_expected.not_to match('https:\/\/example.com/home') }
-      end
-    end
-  end
-end
diff --git a/spec/models/alchemy/ingredient_validator_spec.rb b/spec/models/alchemy/ingredient_validator_spec.rb
index 5e19eaca75..8b3e32f5d3 100644
--- a/spec/models/alchemy/ingredient_validator_spec.rb
+++ b/spec/models/alchemy/ingredient_validator_spec.rb
@@ -56,6 +56,23 @@
 
       it { expect(ingredient.errors).to be_present }
     end
+
+    context "an element with email format validation" do
+      let(:element) { create(:alchemy_element, :with_ingredients, name: "contactform") }
+      let(:ingredient) { element.ingredient_by_role(:mail_from) }
+
+      context "and the value is matching" do
+        let(:value) { "my_email@example.com" }
+
+        it { expect(ingredient.errors).to be_blank }
+      end
+
+      context "and the value is not matching" do
+        let(:value) { "my_email@example" }
+
+        it { expect(ingredient.errors).to be_present }
+      end
+    end
   end
 
   context "an element with url format validation" do
diff --git a/spec/models/alchemy/message_spec.rb b/spec/models/alchemy/message_spec.rb
index 70ebcd7b98..a558858ed1 100644
--- a/spec/models/alchemy/message_spec.rb
+++ b/spec/models/alchemy/message_spec.rb
@@ -7,12 +7,12 @@
 
   describe ".config" do
     it "should return the mailer config" do
-      expect(Alchemy::Message.config).to eq(Alchemy::Config.get(:mailer))
+      expect(Alchemy::Message.config).to eq(Alchemy.config.get(:mailer))
     end
   end
 
   it "has attributes writers and getters for all fields defined in mailer config" do
-    Alchemy::Config.get(:mailer)["fields"].each do |field|
+    Alchemy.config.get(:mailer)["fields"].each do |field|
       expect(message).to respond_to(field)
       expect(message).to respond_to("#{field}=")
     end
@@ -21,7 +21,7 @@
   context "validation of" do
     context "all fields defined in mailer config" do
       it "adds errors on that fields" do
-        Alchemy::Config.get(:mailer)["validate_fields"].each do |field|
+        Alchemy.config.get(:mailer)["validate_fields"].each do |field|
           expect(message).to_not be_valid
           expect(message.errors[field].size).to eq(1)
         end
diff --git a/spec/requests/alchemy/admin/pages_controller_spec.rb b/spec/requests/alchemy/admin/pages_controller_spec.rb
index 8ee33af0df..775ac74489 100644
--- a/spec/requests/alchemy/admin/pages_controller_spec.rb
+++ b/spec/requests/alchemy/admin/pages_controller_spec.rb
@@ -296,9 +296,7 @@ module Alchemy
 
         context "when layout is set to custom" do
           before do
-            allow(Alchemy::Config).to receive(:get) do |arg|
-              (arg == :admin_page_preview_layout) ? "custom" : Alchemy::Config.parameter(arg)
-            end
+            stub_alchemy_config(:admin_page_preview_layout, "custom")
           end
 
           it "it renders custom layout instead" do