diff --git a/app/assets/javascripts/order.js b/app/assets/javascripts/order.js
index baf0c5f4..c7e49b20 100644
--- a/app/assets/javascripts/order.js
+++ b/app/assets/javascripts/order.js
@@ -90,18 +90,20 @@ $(document).off('change', '[class^="ajax-update-all-link-"] select').on('change'
   });
 });
 
-$(document).off('change', '[class^="ajax-update-link-"] select').on('change', '[class^="ajax-update-link-"] select', function () {
+$(document).off('change', '.ajax-update-sepa-select').on('change', '.ajax-update-sepa-select', function () {
   var selectedValue = $(this).val();
-  var url = $(this).closest('a').attr('href');
+  var url = $(this).data('url');
+  console.log(url);
+  console.log(selectedValue);
   $.ajax({
     url: url,
     method: 'PATCH',
     data: { sepa_sequence_type: selectedValue },
     success: function (response) {
-      // Handle success response
+      console.log("succeeded");
     },
     error: function (error) {
-      console.log(error);
+      console.error(error);
     }
   });
 });
@@ -132,6 +134,7 @@ $(document).on('ready turbolinks:load', function () {
 });
 
 $(document).on('click', '.merge-orders-btn', function () {
+
   const url = $(this).data('url');
   const selectedOrderIds = $('input[name="order_ids_for_multi_order[]"]:checked').map(function () {
     return $(this).val();
diff --git a/app/controllers/concerns/send_group_order_invoice_pdf.rb b/app/controllers/concerns/send_group_order_invoice_pdf.rb
index 0734ea2d..76e71c99 100644
--- a/app/controllers/concerns/send_group_order_invoice_pdf.rb
+++ b/app/controllers/concerns/send_group_order_invoice_pdf.rb
@@ -7,14 +7,6 @@ module Concerns::SendGroupOrderInvoicePdf
     invoice_data = group_order_invoice.load_data_for_invoice
     invoice_data[:title] = t('documents.group_order_invoice_pdf.title', supplier: invoice_data[:supplier])
     invoice_data[:no_footer] = true
-    puts "
-    " + "____________" + "
-    " + "____________" + "
-    " + "____________" + "
-    " + "#{invoice_data.inspect}" + "
-    " + "____________"+ "
-    " + "____________"+ "
-    " + "____________"
     GroupOrderInvoicePdf.new invoice_data
   end
 
diff --git a/app/controllers/finance/invoices_controller.rb b/app/controllers/finance/invoices_controller.rb
index d70b92ec..c85ae16b 100644
--- a/app/controllers/finance/invoices_controller.rb
+++ b/app/controllers/finance/invoices_controller.rb
@@ -1,4 +1,4 @@
-class Finance::InvoicesController < ApplicationController
+class Finance::InvoicesController < OrderInvoiceControllerBase
   before_action :authenticate_finance_or_invoices
 
   before_action :find_invoice, only: %i[show edit update destroy]
diff --git a/app/controllers/group_order_invoices_controller.rb b/app/controllers/group_order_invoices_controller.rb
index c72854b5..4994515a 100644
--- a/app/controllers/group_order_invoices_controller.rb
+++ b/app/controllers/group_order_invoices_controller.rb
@@ -1,6 +1,5 @@
-class GroupOrderInvoicesController < ApplicationController
+class GroupOrderInvoicesController < OrderInvoicesControllerBase
   include Concerns::SendGroupOrderInvoicePdf
-  before_action :authenticate_finance
 
   def show
     @group_order_invoice = GroupOrderInvoice.find(params[:id])
@@ -57,21 +56,6 @@ class GroupOrderInvoicesController < ApplicationController
     end
   end
 
-  def select_sepa_sequence_type
-    @group_order_invoice = GroupOrderInvoice.find(params[:id])
-    @group_order = @group_order_invoice.group_order
-    return unless params[:sepa_sequence_type]
-
-    respond_to do |format|
-      @group_order_invoice.sepa_sequence_type = params[:sepa_sequence_type]
-      if @group_order_invoice.save!
-        format.js
-      else
-        format.json { render json: @group_order_invoice.errors, status: :unprocessable_entity }
-      end
-    end
-  end
-
   def select_all_sepa_sequence_type
     @order = Order.find(params[:order_id])
     @group_order_invoices = @order.group_orders.map(&:group_order_invoice).compact
@@ -86,31 +70,6 @@ class GroupOrderInvoicesController < ApplicationController
     end
   end
 
-  def toggle_paid
-    @group_order_invoice = GroupOrderInvoice.find(params[:id])
-    respond_to do |format|
-      @group_order_invoice.paid = !@group_order_invoice.paid
-      if @group_order_invoice.save!
-        format.js
-      else
-        format.json { render json: @group_order_invoice.errors, status: :unprocessable_entity }
-      end
-    end
-  end
-
-  def toggle_sepa_downloaded
-    @group_order_invoice = GroupOrderInvoice.find(params[:id])
-    @order = @group_order_invoice.group_order.order
-    respond_to do |format|
-      @group_order_invoice.sepa_downloaded = !@group_order_invoice.sepa_downloaded
-      if @group_order_invoice.save!
-        format.js
-      else
-        format.json { render json: @group_order_invoice.errors, status: :unprocessable_entity }
-      end
-    end
-  end
-
   def toggle_all_paid
     @order = Order.find(params[:order_id])
     @group_order_invoices = @order.group_orders.map(&:group_order_invoice).compact
@@ -164,4 +123,14 @@ class GroupOrderInvoicesController < ApplicationController
       end
     end
   end
+
+  protected
+
+  def invoice_class
+    GroupOrderInvoice
+  end
+
+  def set_related_group_order(invoice)
+    invoice.group_order
+  end
 end
diff --git a/app/controllers/multi_orders_controller.rb b/app/controllers/multi_orders_controller.rb
index f762a72c..68e9f174 100644
--- a/app/controllers/multi_orders_controller.rb
+++ b/app/controllers/multi_orders_controller.rb
@@ -39,27 +39,18 @@ class MultiOrdersController < ApplicationController
       end
       return
     end
-
     begin
       @multi_order = MultiOrder.new
       @multi_order.orders = orders
       @multi_order.ends = orders.map(&:ends).max
       @multi_order.save!
-      #create multi group orders
-      all_group_orders = orders.flat_map(&:group_orders)
-
-      grouped_by_ordergroup = all_group_orders.group_by(&:ordergroup_id)
-
-      grouped_by_ordergroup.each do |ordergroup_id, group_orders|
-        multi_group_order = MultiGroupOrder.create!(
-          multi_order: @multi_order, group_orders: group_orders
-        )
-        # Now, associate each group_order with the new multi_group_order
-        group_orders.each do |group_order|
-          group_order.update!(multi_group_order: multi_group_order)
-        end
+      suppliers = orders.map(&:supplier).map(&:name).join(', ')
+      msg = "Multi Bestellung für #{suppliers} erstellt"
+      respond_to do |format|
+        flash[:notice] = msg
+        format.js
+        format.html { redirect_to finance_order_index_path }
       end
-      redirect_to finance_order_index_path
     rescue ActiveRecord::RecordInvalid => e
       flash[:alert] = t('errors.general_msg', msg: e.message)
       respond_to do |format|
@@ -71,9 +62,13 @@ class MultiOrdersController < ApplicationController
 
   def destroy
     @multi_order = MultiOrder.find(params[:id])
-    @multi_order.destroy
-    respond_to do |format|
-      format.html { redirect_to finance_order_index_path }
+    if @multi_order.ordergroup_invoices.any?
+      flash[:alert]= "Lösche erst die Rechnungen"
+      redirect_to finance_order_index_path
+    else
+      @multi_order.destroy
+      redirect_to finance_order_index_path
+
     end
   end
 
diff --git a/app/controllers/order_invoices_controller_base.rb b/app/controllers/order_invoices_controller_base.rb
new file mode 100644
index 00000000..77442945
--- /dev/null
+++ b/app/controllers/order_invoices_controller_base.rb
@@ -0,0 +1,44 @@
+class OrderInvoicesControllerBase < ApplicationController
+  before_action :authenticate_finance
+
+  def select_sepa_sequence_type
+    @invoice = invoice_class.find(params[:id])
+    return unless params[:sepa_sequence_type]
+
+    @group_order = set_related_group_order(@invoice)
+    @multi_group_order = set_related_group_order(@invoice)
+
+    @invoice.sepa_sequence_type = params[:sepa_sequence_type]
+    save_and_respond(@invoice)
+  end
+
+  def toggle_paid
+    @invoice = invoice_class.find(params[:id])
+    @invoice.paid = !@invoice.paid
+    save_and_respond(@invoice)
+  end
+
+  def toggle_sepa_downloaded
+    @invoice = invoice_class.find(params[:id])
+    @invoice.sepa_downloaded = !@invoice.sepa_downloaded
+    save_and_respond(@invoice)
+  end
+
+  protected
+
+  def save_and_respond(record)
+    if record.save!
+      respond_to { |format| format.js }
+    else
+      respond_to { |format| format.json { render json: record.errors, status: :unprocessable_entity } }
+    end
+  end
+
+  def invoice_class
+    raise NotImplementedError
+  end
+
+  def set_related_group_order(invoice)
+    raise NotImplementedError
+  end
+end
diff --git a/app/controllers/ordergroup_invoices_controller.rb b/app/controllers/ordergroup_invoices_controller.rb
index edffe596..2d0525ea 100644
--- a/app/controllers/ordergroup_invoices_controller.rb
+++ b/app/controllers/ordergroup_invoices_controller.rb
@@ -1,15 +1,12 @@
 
-class OrdergroupInvoicesController < ApplicationController
+class OrdergroupInvoicesController < OrderInvoicesControllerBase
   include Concerns::SendGroupOrderInvoicePdf
-  before_action :authenticate_finance
-  # download create and new ordergroupinvoice
-  # has multiple group orders and one ordergroup
 
-  def new
-    @ordergroup_invoice = OrdergroupInvoice.new
-    @ordergroup_invoice.payment_method = FoodsoftConfig[:ordergroup_invoices][:payment_method] || I18n.t('activerecord.attributes.ordergroup_invoice.payment_method')
-    @ordergroup_invoice.sepa_sequence_type = params[:sepa_sequence_type]
-  end
+  # def new
+  #   @ordergroup_invoice = OrdergroupInvoice.new
+  #   @ordergroup_invoice.payment_method = FoodsoftConfig[:ordergroup_invoices][:payment_method] || I18n.t('activerecord.attributes.ordergroup_invoice.payment_method')
+  #   @ordergroup_invoice.sepa_sequence_type = params[:sepa_sequence_type]
+  # end
 
   def show
     @ordergroup_invoice = OrdergroupInvoice.find(params[:id])
@@ -67,18 +64,15 @@ class OrdergroupInvoicesController < ApplicationController
     end
   end
 
-
-  def select_sepa_sequence_type
-    @ordergroup_invoice = OrdergroupInvoice.find(params[:id])
-    @multi_group_order = @ordergroup_invoice.multi_group_order
-    return unless params[:sepa_sequence_type]
-
+  def send_all
+    @multi_order = MultiOrder.find(params[:multi_order_id])
+    @ordergroup_invoices = @multi_order.multi_group_orders.map(&:ordergroup_invoice).compact
+    @ordergroup_invoices.each do |oi|
+      oi.send_invoice
+    end
     respond_to do |format|
-      @ordergroup_invoice.sepa_sequence_type = params[:sepa_sequence_type]
-      if @ordergroup_invoice.save!
-        format.js
-      else
-        format.json { render json: @ordergroup_invoice.errors, status: :unprocessable_entity }
+      format.html do
+        redirect_to finance_order_index_path, notice: I18n.t('ordergroup_invoices.send_all.success')
       end
     end
   end
@@ -97,31 +91,6 @@ class OrdergroupInvoicesController < ApplicationController
     end
   end
 
-  def toggle_paid
-    @ordergroup_invoice = OrdergroupInvoice.find(params[:id])
-    respond_to do |format|
-      @ordergroup_invoice.paid = !@ordergroup_invoice.paid
-      if @ordergroup_invoice.save!
-        format.js
-      else
-        format.json { render json: @ordergroup_invoice.errors, status: :unprocessable_entity }
-      end
-    end
-  end
-
-  def toggle_sepa_downloaded
-    @ordergroup_invoice = OrdergroupInvoice.find(params[:id])
-    @multi_order= @ordergroup_invoice.multi_group_order.multi_order
-    respond_to do |format|
-      @ordergroup_invoice.sepa_downloaded = !@ordergroup_invoice.sepa_downloaded
-      if @ordergroup_invoice.save!
-        format.js
-      else
-        format.json { render json: @ordergroup_invoice.errors, status: :unprocessable_entity }
-      end
-    end
-  end
-
   def toggle_all_paid
     @multi_order= MultiOrder.find(params[:multi_order_id])
     @ordergroup_invoices = @multi_order.multi_group_orders.map(&:ordergroup_invoice).compact
@@ -175,5 +144,12 @@ class OrdergroupInvoicesController < ApplicationController
       end
     end
   end
+  protected
+  def invoice_class
+    OrdergroupInvoice
+  end
 
+  def set_related_group_order(invoice)
+    invoice.multi_group_order
+  end
 end
diff --git a/app/helpers/invoice_helper.rb b/app/helpers/invoice_helper.rb
index 36d511cc..41ff2d36 100644
--- a/app/helpers/invoice_helper.rb
+++ b/app/helpers/invoice_helper.rb
@@ -1,4 +1,12 @@
 module InvoiceHelper
+
+  SEPA_SEQUENCE_TYPES = {
+    FRST: "Erst-Lastschrift",
+    RCUR: "Folge-Lastschrift",
+    OOFF: "Einmalige Lastschrift",
+    FNAL: "Letztmalige Lastschrift"
+  }.freeze
+
   def generate_invoice_number(instance, count)
     trailing_number = count.to_s.rjust(4, '0')
     if GroupOrderInvoice.find_by(invoice_number: instance.invoice_date.strftime("%Y%m%d") + trailing_number) || OrdergroupInvoice.find_by(invoice_number: instance.invoice_date.strftime("%Y%m%d") + trailing_number)
diff --git a/app/jobs/notify_ordergroup_invoice_job.rb b/app/jobs/notify_ordergroup_invoice_job.rb
new file mode 100644
index 00000000..b218745b
--- /dev/null
+++ b/app/jobs/notify_ordergroup_invoice_job.rb
@@ -0,0 +1,12 @@
+class NotifyOrdergroupInvoiceJob < ApplicationJob
+    def perform(ordergroup_invoice)
+      ordergroup = ordergroup_invoice.multi_group_order.ordergroup
+      ordergroup.users.each do |user|
+        ordergroup_invoice.update!(email_sent_at: Time.current)
+        Mailer.deliver_now_with_user_locale user do
+          Mailer.ordergroup_invoice(ordergroup_invoice, user)
+        end
+      end
+    end
+  end
+  
\ No newline at end of file
diff --git a/app/mailers/mailer.rb b/app/mailers/mailer.rb
index 2b06ce8e..152c8b28 100644
--- a/app/mailers/mailer.rb
+++ b/app/mailers/mailer.rb
@@ -63,6 +63,18 @@ class Mailer < ActionMailer::Base
          subject: I18n.t('mailer.group_order_invoice.subject', group: @group.name, supplier: @supplier)
   end
 
+  def ordergroup_invoice(ordergroup_invoice, user)
+    @user = user
+    @ordergroup_invoice = ordergroup_invoice
+    @multi_group_order = ordergroup_invoice.multi_group_order
+    @multi_order = @multi_group_order.multi_order
+    @supplier = @multi_order.orders.map(&:supplier).map(&:name).uniq.join(', ')
+    @group = @multi_group_order.ordergroup
+    add_ordergroup_invoice_attachments(ordergroup_invoice)
+    mail to: user,
+         subject: I18n.t('mailer.ordergroup_invoice.subject', group: @group.name, supplier: @supplier)
+  end
+
   # Sends order result for specific Ordergroup
   def order_result(user, group_order)
     @order        = group_order.order
@@ -186,6 +198,10 @@ class Mailer < ActionMailer::Base
     attachments[attachment_name] = GroupOrderInvoicePdf.new(group_order_invoice.load_data_for_invoice).to_pdf
   end
 
+  def add_ordergroup_invoice_attachments(ordergroup_invoice)
+    add_group_order_invoice_attachments(ordergroup_invoice)
+  end
+
   # separate method to allow plugins to mess with the text
   def additonal_welcome_text(user); end
 
diff --git a/app/models/concerns/invoice_common.rb b/app/models/concerns/invoice_common.rb
new file mode 100644
index 00000000..7f9b8d87
--- /dev/null
+++ b/app/models/concerns/invoice_common.rb
@@ -0,0 +1,34 @@
+# app/models/concerns/invoice_common.rb
+module InvoiceCommon
+    extend ActiveSupport::Concern
+  
+    included do
+      include InvoiceHelper
+  
+      validates_presence_of :invoice_number
+      validates_uniqueness_of :invoice_number
+      validate :tax_number_set
+  
+      after_initialize :init, unless: :persisted?
+    end
+  
+    def mark_sepa_downloaded
+      self.sepa_downloaded = true
+      save
+    end
+  
+    def unmark_sepa_downloaded
+      self.sepa_downloaded = false
+      save
+    end
+  
+    def name
+      I18n.t("activerecord.attributes.#{self.class.name.underscore}.name") + "_#{invoice_number}"
+    end
+  
+    def tax_number_set
+      return if FoodsoftConfig[:contact][:tax_number].present?
+      errors.add(:base, "Keine Steuernummer in FoodsoftConfig :contact gesetzt")
+    end
+  end
+  
\ No newline at end of file
diff --git a/app/models/group_order.rb b/app/models/group_order.rb
index 2045ac12..6dbc8d09 100644
--- a/app/models/group_order.rb
+++ b/app/models/group_order.rb
@@ -11,7 +11,7 @@ class GroupOrder < ApplicationRecord
   has_one :financial_transaction
   has_one :group_order_invoice
   belongs_to :ordergroup_invoice, optional: true
-  belongs_to :multi_group_order, optional: true, dependent: :destroy
+  belongs_to :multi_group_order, optional: true
   belongs_to :multi_order, optional: true
   belongs_to :updated_by, optional: true, class_name: 'User', foreign_key: 'updated_by_user_id'
 
diff --git a/app/models/group_order_invoice.rb b/app/models/group_order_invoice.rb
index 8fcb65f9..310e082b 100644
--- a/app/models/group_order_invoice.rb
+++ b/app/models/group_order_invoice.rb
@@ -1,34 +1,9 @@
 class GroupOrderInvoice < ApplicationRecord
-  include InvoiceHelper
+  include InvoiceCommon
 
   belongs_to :group_order
   validates_presence_of :group_order
-  validates_uniqueness_of :invoice_number
-  validate :tax_number_set
-  after_initialize :init, unless: :persisted?
-
-  enum sequence_type: {
-    FRST: "Erst-Lastschrift",
-    RCUR: "Folge-Lastschrift",
-    OOFF: "Einmalige Lastschrift",
-    FNAL: "Letztmalige Lastschrift"
-  }
-
-  def tax_number_set
-    return unless FoodsoftConfig[:contact][:tax_number].blank?
-
-    errors.add(:group_order_invoice, "Keine Steuernummer in FoodsoftConfig :contact gesetzt")
-  end
-
-  def mark_sepa_downloaded
-    self.sepa_downloaded = true
-    self.save
-  end
-
-  def unmark_sepa_downloaded
-    self.sepa_downloaded = false
-    self.save
-  end
+  validates_uniqueness_of :group_order_id
 
   def init
     self.invoice_date = Time.now unless invoice_date
@@ -36,10 +11,6 @@ class GroupOrderInvoice < ApplicationRecord
     self.payment_method = group_order&.financial_transaction&.financial_transaction_type&.name || FoodsoftConfig[:group_order_invoices]&.[](:payment_method) || I18n.t('activerecord.attributes.group_order_invoice.payment_method') unless self.payment_method
   end
 
-  def name
-    I18n.t('activerecord.attributes.group_order_invoice.name') + "_#{invoice_number}"
-  end
-
   def load_data_for_invoice
     invoice_data = {}
     order = group_order.order
diff --git a/app/models/multi_group_order.rb b/app/models/multi_group_order.rb
index 9cb89aad..7a66afb0 100644
--- a/app/models/multi_group_order.rb
+++ b/app/models/multi_group_order.rb
@@ -1,8 +1,10 @@
 class MultiGroupOrder < ApplicationRecord
-  belongs_to :multi_order
-  has_many :group_orders
+  belongs_to :multi_order, optional: false
+  has_many :group_orders, dependent: :nullify
   has_one :ordergroup_invoice, dependent: :destroy
 
+  validates :multi_order, presence: true
+
   def ordergroup
     group_orders.first&.ordergroup
   end
diff --git a/app/models/multi_order.rb b/app/models/multi_order.rb
index c6ab683f..78253bde 100644
--- a/app/models/multi_order.rb
+++ b/app/models/multi_order.rb
@@ -6,11 +6,10 @@ class MultiOrder < ApplicationRecord
   #TODO: diese association lösen
   has_many :group_orders, through: :multi_group_orders
   # has_many :ordergroups, through: :group_orders
-  has_many :ordergroup_invoices, through: :group_orders
+  has_many :ordergroup_invoices, through: :multi_group_orders
 
-  #make sure order has no multi_order_id
-  #make sure orders are not in a multi_order
-  before_create :check_orders
+  validate :check_orders
+  after_create :create_multi_group_orders
 
   def name
     orders.map(&:name).join(', ')
@@ -40,15 +39,38 @@ class MultiOrder < ApplicationRecord
   end
   
   private
+
   def check_orders
-    orders.each do |order|
-      errors.add(:base, "Order #{order.name} is already in a multi order") unless order.multi_order_id.nil?
-      #closed==abgerechnet
-      errors.add(:base, "Order #{order.name} not closed") unless order.closed?
+    unless orders.present?
+      errors.add(:base, "No orders selected")
+      return
     end
-    if errors.any?
-      errors.add(:base, "Cannot create multi order with unfinished orders")
-      raise ActiveRecord::Rollback
+    orders.each do |order|
+      if order.group_orders.blank?
+        errors.add(:base, "Order #{order.name} has no group orders")
+      end
+      unless order.closed? 
+        errors.add(:base, "Order #{order.name} is not closed")
+      end
+      if order.group_orders.any? { |go| go.group_order_invoice.present? }
+        errors.add(:base, "Order #{order.name} has group order invoices")
+      end
+    end
+  end
+
+  def create_multi_group_orders
+    return if orders.empty?
+    all_group_orders = orders.flat_map(&:group_orders)
+    grouped_by_ordergroup = all_group_orders.group_by(&:ordergroup_id)
+
+    grouped_by_ordergroup.each do |ordergroup_id, group_orders|
+      multi_group_order = MultiGroupOrder.create!(
+        multi_order: self, group_orders: group_orders
+      )
+      # Now, associate each group_order with the new multi_group_order
+      group_orders.each do |group_order|
+        group_order.update!(multi_group_order: multi_group_order)
+      end
     end
   end
 end
diff --git a/app/models/ordergroup_invoice.rb b/app/models/ordergroup_invoice.rb
index 02eda363..1b1e4414 100644
--- a/app/models/ordergroup_invoice.rb
+++ b/app/models/ordergroup_invoice.rb
@@ -1,25 +1,10 @@
 class OrdergroupInvoice < ApplicationRecord
-  include InvoiceHelper
+  include InvoiceCommon
 
-  belongs_to :multi_group_order, optional: true
+  belongs_to :multi_group_order
 
-  # has_many :group_orders, through: :multi_group_order, dependent: :nullify
-
-  validates_presence_of :invoice_number
-  validates_uniqueness_of :invoice_number
-  validate :tax_number_set
   after_initialize :init, unless: :persisted?
 
-  # accepts_nested_attributes_for :group_orders, :multi_group_order
-
-
-  enum sequence_type: {
-    FRST: "Erst-Lastschrift",
-    RCUR: "Folge-Lastschrift",
-    OOFF: "Einmalige Lastschrift",
-    FNAL: "Letztmalige Lastschrift"
-  }
-
   def init
     self.invoice_date = Time.now unless invoice_date
     self.invoice_number = generate_invoice_number(self, 1) unless self.invoice_number
@@ -32,24 +17,8 @@ class OrdergroupInvoice < ApplicationRecord
     group_orders.first.ordergroup
   end
 
-  def tax_number_set
-    return if FoodsoftConfig[:contact][:tax_number].present?
-
-    errors.add(:cumulative_invoice, "Keine Steuernummer in FoodsoftConfig :contact gesetzt")
-  end
-
-  def mark_sepa_downloaded
-    self.sepa_downloaded = true
-    self.save
-  end
-
-  def unmark_sepa_downloaded
-    self.sepa_downloaded = false
-    self.save
-  end
-
-  def name
-    I18n.t('activerecord.attributes.ordergroup_invoice.name') + "_#{invoice_number}"
+  def send_invoice
+    NotifyOrdergroupInvoiceJob.perform_now(self)
   end
 
   def load_data_for_invoice
diff --git a/app/views/group_order_invoices/_select_all_sepa_sequence_type.html.haml b/app/views/group_order_invoices/_select_all_sepa_sequence_type.html.haml
index 9caffeb1..a7b3deca 100644
--- a/app/views/group_order_invoices/_select_all_sepa_sequence_type.html.haml
+++ b/app/views/group_order_invoices/_select_all_sepa_sequence_type.html.haml
@@ -1,2 +1,2 @@
 = link_to select_all_sepa_sequence_type_group_order_invoices_path(order_id: order.id), remote: true, method: :patch, class: "ajax-update-all-link-#{order.id}" , data: { turbolinks: false } do
-  = select_tag 'sepa_sequence_type', options_for_select(GroupOrderInvoice.sequence_types.keys.map { |st| [I18n.t("activerecord.attributes.group_order_invoice.sequence_type.#{st}"), st] }, selected: @sequence_type || order.group_orders.map(&:group_order_invoice)&.compact&.first.sepa_sequence_type), class: 'form-control', id: "all_sepa_sequence_type_#{order.id}"
\ No newline at end of file
+  = select_tag 'sepa_sequence_type', options_for_select(InvoiceHelper::SEPA_SEQUENCE_TYPES.keys.map { |st| [I18n.t("activerecord.attributes.group_order_invoice.sequence_type.#{st}"), st] }, selected: @sequence_type || order.group_orders.map(&:group_order_invoice)&.compact&.first.sepa_sequence_type), class: 'form-control', id: "all_sepa_sequence_type_#{order.id}"
\ No newline at end of file
diff --git a/app/views/group_order_invoices/_select_sepa_sequence_type.html.haml b/app/views/group_order_invoices/_select_sepa_sequence_type.html.haml
index 1c930df1..c4121b5e 100644
--- a/app/views/group_order_invoices/_select_sepa_sequence_type.html.haml
+++ b/app/views/group_order_invoices/_select_sepa_sequence_type.html.haml
@@ -1,2 +1 @@
-= link_to select_sepa_sequence_type_group_order_invoice_path(group_order_invoice), remote: true, method: :patch, class: "ajax-update-link-#{group_order.id}", data: { turbolinks: false } do
-  = select_tag 'sepa_sequence_type', options_for_select(GroupOrderInvoice.sequence_types.keys.map { |st| [I18n.t("activerecord.attributes.group_order_invoice.sequence_type.#{st}"), st] }, selected: group_order_invoice.sepa_sequence_type ), class: 'form-control', id: "sepa_sequence_type_#{group_order.id}"
\ No newline at end of file
+= select_tag :sepa_sequence_type, options_for_select(InvoiceHelper::SEPA_SEQUENCE_TYPES.map { |k, v| [v, k] }, group_order_invoice.sepa_sequence_type), class: 'form-control ajax-update-sepa-select', id: "sepa_sequence_type_multi_#{group_order.id}", data: { url: select_sepa_sequence_type_group_order_invoice_path(group_order_invoice) }
\ No newline at end of file
diff --git a/app/views/group_order_invoices/select_sepa_sequence_type.js.erb b/app/views/group_order_invoices/select_sepa_sequence_type.js.erb
index 96bf519f..d92ef8ed 100644
--- a/app/views/group_order_invoices/select_sepa_sequence_type.js.erb
+++ b/app/views/group_order_invoices/select_sepa_sequence_type.js.erb
@@ -1 +1 @@
-$("#select_sepa_sequence_type_<%= @group_order_invoice.id %>").html("<%= j(render partial: 'select_sepa_sequence_type', locals: {group_order_invoice: @group_order_invoice, group_order: @group_order}) %>");
\ No newline at end of file
+$("#select_sepa_sequence_type_<%= @invoice.id %>").html("<%= j(render partial: 'select_sepa_sequence_type', locals: {group_order_invoice: @invoice, group_order: @group_order}) %>");
diff --git a/app/views/mailer/ordergroup_invoice.text.haml b/app/views/mailer/ordergroup_invoice.text.haml
new file mode 100644
index 00000000..75948fbe
--- /dev/null
+++ b/app/views/mailer/ordergroup_invoice.text.haml
@@ -0,0 +1 @@
+= raw t '.text', group: @group.name, supplier: @supplier , foodcoop: FoodsoftConfig[:name]
diff --git a/app/views/ordergroup_invoices/_links.html.haml b/app/views/ordergroup_invoices/_links.html.haml
index 5153b362..0abd0570 100644
--- a/app/views/ordergroup_invoices/_links.html.haml
+++ b/app/views/ordergroup_invoices/_links.html.haml
@@ -25,26 +25,29 @@
   %tbody
     - multi_order.multi_group_orders.each do |mgo|
       -if mgo.ordergroup_invoice.present?
-        - if mgo.ordergroup_invoice
-          %tr.order-row{id: "multi_group_order_#{mgo.id}"}
-            %td
-              = link_to mgo.ordergroup&.name, edit_admin_ordergroup_path(mgo.ordergroup)
-            %td
-              .div{id: "paid_multi_#{mgo.ordergroup_invoice.id}"}
-                = render :partial => "ordergroup_invoices/toggle_paid", locals: { ordergroup_invoice: mgo.ordergroup_invoice }
-            %td
-              .div{id: "sepa_downloaded_multi_#{mgo.ordergroup_invoice.id}"}
-                = render :partial => "ordergroup_invoices/toggle_sepa_downloaded", locals: { ordergroup_invoice: mgo.ordergroup_invoice }
-            %td
-              .div{id: "select_sepa_sequence_type_multi_#{mgo.ordergroup_invoice.id}"}
-                =render :partial => 'ordergroup_invoices/select_sepa_sequence_type', locals:{ ordergroup_invoice: mgo.ordergroup_invoice, multi_group_order: mgo }
-            %td
-              = check_box_tag "group_order_ids_for_multi_order_#{multi_order.id}", mgo.id, false, class: "group-order-checkbox", id: "group_order_#{mgo.id}_included_in_sepa", data: { multi_group_order_id: mgo.id }
-            %td
-              %b= mgo.ordergroup_invoice.invoice_number
-            %td
-              = link_to  I18n.t('activerecord.attributes.group_order_invoice.links.delete'), mgo.ordergroup_invoice, method: :delete, class: 'btn btn-block btn-danger', remote: true, data: { confirm: I18n.t('ui.confirm_delete', name: "Bestellgruppenrechnung für #{mgo.ordergroup.name}" ) }
-              = link_to I18n.t('activerecord.attributes.group_order_invoice.links.download'), ordergroup_invoice_path(mgo.ordergroup_invoice, :format => 'pdf'), class: 'btn btn-block'
+        %tr.order-row{id: "multi_group_order_#{mgo.id}"}
+          %td
+            = link_to mgo.ordergroup&.name, edit_admin_ordergroup_path(mgo.ordergroup)
+          %td
+            .div{id: "paid_multi_#{mgo.ordergroup_invoice.id}"}
+              = render :partial => "ordergroup_invoices/toggle_paid", locals: { ordergroup_invoice: mgo.ordergroup_invoice }
+          %td
+            .div{id: "sepa_downloaded_multi_#{mgo.ordergroup_invoice.id}"}
+              = render :partial => "ordergroup_invoices/toggle_sepa_downloaded", locals: { ordergroup_invoice: mgo.ordergroup_invoice }
+          %td
+            .div{id: "select_sepa_sequence_type_multi_#{mgo.ordergroup_invoice.id}"}
+              =render :partial => 'ordergroup_invoices/select_sepa_sequence_type', locals:{ ordergroup_invoice: mgo.ordergroup_invoice, multi_group_order: mgo }
+          %td
+            = check_box_tag "group_order_ids_for_multi_order_#{multi_order.id}", mgo.id, false, class: "group-order-checkbox", id: "group_order_#{mgo.id}_included_in_sepa", data: { multi_group_order_id: mgo.id }
+          %td
+            %b= mgo.ordergroup_invoice.invoice_number
+            - if mgo.ordergroup_invoice.email_sent_at.present?
+              %br/
+              = I18n.t('activerecord.attributes.ordergroup_invoice.email_sent')
+              = mgo.ordergroup_invoice.email_sent_at.strftime("%d.%m.%Y %H:%M")
+          %td
+            = link_to  I18n.t('activerecord.attributes.group_order_invoice.links.delete'), mgo.ordergroup_invoice, method: :delete, class: 'btn btn-block btn-danger', remote: true, data: { confirm: I18n.t('ui.confirm_delete', name: "Bestellgruppenrechnung für #{mgo.ordergroup.name}" ) }
+            = link_to I18n.t('activerecord.attributes.group_order_invoice.links.download'), ordergroup_invoice_path(mgo.ordergroup_invoice, :format => 'pdf'), class: 'btn btn-block'
       - else
         %tr
           %td
@@ -70,5 +73,8 @@
         %td
           .div{id: "select_all_sepa_#{multi_order.id}"}
             = render :partial => 'ordergroup_invoices/collective_direct_debit', locals: { multi_order: multi_order }
+        %td
         %td
           = link_to I18n.t('activerecord.attributes.group_order_invoice.links.download_all_zip'), download_all_ordergroup_invoices_path(multi_order), class: 'btn btn-block'
+          -# sends all ordergroup invoices to the ordergoups mail address via notifyjob
+          = link_to I18n.t('activerecord.attributes.group_order_invoice.links.send_all_by_email'), send_all_ordergroup_invoices_path(multi_order), class: 'btn btn-block', method: :post, data: { confirm: I18n.t('activerecord.attributes.group_order_invoice.links.confirm_send_all', ordergroups: "#{multi_order.multi_group_orders.map(&:ordergroup).map(&:name).join(', ')}" ) }
diff --git a/app/views/ordergroup_invoices/_select_all_sepa_sequence_type.html.haml b/app/views/ordergroup_invoices/_select_all_sepa_sequence_type.html.haml
index a4dc9580..01c26923 100644
--- a/app/views/ordergroup_invoices/_select_all_sepa_sequence_type.html.haml
+++ b/app/views/ordergroup_invoices/_select_all_sepa_sequence_type.html.haml
@@ -1,2 +1,2 @@
 = link_to select_all_sepa_sequence_type_ordergroup_invoices_path(multi_order_id: multi_order.id), remote: true, method: :patch, class: "ajax-update-all-link-#{multi_order.id}" , data: { turbolinks: false } do
-  = select_tag 'sepa_sequence_type', options_for_select(OrdergroupInvoice.sequence_types.keys.map { |st| [I18n.t("activerecord.attributes.group_order_invoice.sequence_type.#{st}"), st] }, selected: @sequence_type || multi_order.multi_group_orders.map(&:ordergroup_invoice)&.compact&.first&.sepa_sequence_type), class: 'form-control', id: "all_sepa_sequence_type_multi_#{multi_order.id}"
\ No newline at end of file
+  = select_tag 'sepa_sequence_type', options_for_select(InvoiceHelper::SEPA_SEQUENCE_TYPES.keys.map { |st| [I18n.t("activerecord.attributes.group_order_invoice.sequence_type.#{st}"), st] }, selected: @sequence_type || multi_order.multi_group_orders.map(&:ordergroup_invoice)&.compact&.first&.sepa_sequence_type), class: 'form-control', id: "all_sepa_sequence_type_multi_#{multi_order.id}"
\ No newline at end of file
diff --git a/app/views/ordergroup_invoices/_select_sepa_sequence_type.html.haml b/app/views/ordergroup_invoices/_select_sepa_sequence_type.html.haml
index 61799883..8b92abfd 100644
--- a/app/views/ordergroup_invoices/_select_sepa_sequence_type.html.haml
+++ b/app/views/ordergroup_invoices/_select_sepa_sequence_type.html.haml
@@ -1,2 +1 @@
-= link_to select_sepa_sequence_type_ordergroup_invoice_path(ordergroup_invoice), remote: true, method: :patch, class: "ajax-update-link-#{multi_group_order.id}", data: { turbolinks: false } do
-  = select_tag 'sepa_sequence_type', options_for_select(OrdergroupInvoice.sequence_types.keys.map { |st| [I18n.t("activerecord.attributes.group_order_invoice.sequence_type.#{st}"), st] }, selected: ordergroup_invoice.sepa_sequence_type ), class: 'form-control', id: "sepa_sequence_type_multi_#{multi_group_order.id}"
\ No newline at end of file
+= select_tag :sepa_sequence_type, options_for_select(InvoiceHelper::SEPA_SEQUENCE_TYPES.map { |k, v| [v, k] }, ordergroup_invoice.sepa_sequence_type), class: 'form-control ajax-update-sepa-select', id: "sepa_sequence_type_multi_#{multi_group_order.id}", data: { url: select_sepa_sequence_type_ordergroup_invoice_path(ordergroup_invoice) }
\ No newline at end of file
diff --git a/app/views/ordergroup_invoices/_toggle_sepa_downloaded.html.haml b/app/views/ordergroup_invoices/_toggle_sepa_downloaded.html.haml
index f4bfcbd1..064d1838 100644
--- a/app/views/ordergroup_invoices/_toggle_sepa_downloaded.html.haml
+++ b/app/views/ordergroup_invoices/_toggle_sepa_downloaded.html.haml
@@ -1,2 +1,2 @@
 = link_to toggle_sepa_downloaded_ordergroup_invoice_path(ordergroup_invoice), remote: true, method: :patch do
-  = check_box_tag 'sepa_downloaded', '1', ordergroup_invoice.sepa_downloaded , class: 'form-check-input', id: "sepa_downloaded_multii_#{ordergroup_invoice.id}"
\ No newline at end of file
+  = check_box_tag 'sepa_downloaded', '1', ordergroup_invoice.sepa_downloaded , class: 'form-check-input', id: "sepa_downloaded_multi_#{ordergroup_invoice.id}"
\ No newline at end of file
diff --git a/app/views/ordergroup_invoices/select_sepa_sequence_type.js.erb b/app/views/ordergroup_invoices/select_sepa_sequence_type.js.erb
index fa249c87..b8fe4813 100644
--- a/app/views/ordergroup_invoices/select_sepa_sequence_type.js.erb
+++ b/app/views/ordergroup_invoices/select_sepa_sequence_type.js.erb
@@ -1 +1 @@
-$("#select_sepa_sequence_type_multi_<%= @ordergroup_invoice.id %>").html("<%= j(render partial: 'select_sepa_sequence_type', locals: {ordergroup_invoice: @ordergroup_invoice, multi_group_order: @multi_group_order}) %>");
\ No newline at end of file
+$("#select_sepa_sequence_type_multi_<%= @invoice.id %>").html("<%= j(render partial: 'select_sepa_sequence_type', locals: {ordergroup_invoice: @invoice, multi_group_order: @group_order}) %>");
diff --git a/app/views/ordergroup_invoices/toggle_paid.js.erb b/app/views/ordergroup_invoices/toggle_paid.js.erb
index 4097f4d6..0832d8bf 100644
--- a/app/views/ordergroup_invoices/toggle_paid.js.erb
+++ b/app/views/ordergroup_invoices/toggle_paid.js.erb
@@ -1 +1 @@
-$("#paid_multi_<%= @ordergroup_invoice.id %>").html("<%= escape_javascript(render partial: 'toggle_paid', locals: {ordergroup_invoice: @ordergroup_invoice}) %>");
+$("#paid_multi_<%= @invoice.id %>").html("<%= escape_javascript(render partial: 'toggle_paid', locals: {ordergroup_invoice: @invoice}) %>");
diff --git a/app/views/ordergroup_invoices/toggle_sepa_downloaded.js.erb b/app/views/ordergroup_invoices/toggle_sepa_downloaded.js.erb
index 9a57c052..ffe34b60 100644
--- a/app/views/ordergroup_invoices/toggle_sepa_downloaded.js.erb
+++ b/app/views/ordergroup_invoices/toggle_sepa_downloaded.js.erb
@@ -1 +1 @@
-$("#sepa_downloaded_multi_<%= @ordergroup_invoice.id %>").html("<%= escape_javascript(render partial: 'toggle_sepa_downloaded', locals: {ordergroup_invoice: @ordergroup_invoice}) %>");
+$("#sepa_downloaded_multi_<%= @invoice.id %>").html("<%= escape_javascript(render partial: 'toggle_sepa_downloaded', locals: {ordergroup_invoice: @invoice}) %>");
diff --git a/config/environments/development.rb.SAMPLE b/config/environments/development.rb.SAMPLE
index ed5bb855..40443e01 100644
--- a/config/environments/development.rb.SAMPLE
+++ b/config/environments/development.rb.SAMPLE
@@ -36,6 +36,9 @@ Rails.application.configure do
 
   # Don't care if the mailer can't send.
   config.action_mailer.raise_delivery_errors = false
+  config.action_mailer.perform_deliveries = true
+  config.action_mailer.default_url_options = { host: 'localhost', port: 3000 }
+  config.action_mailer.delivery_method = :letter_opener_web
 
   config.action_mailer.perform_caching = false
 
@@ -57,12 +60,12 @@ Rails.application.configure do
   config.assets.initialize_on_precompile = true
 
   # Configure hostname for action mailer (can be overridden in foodcoop config)
-  config.action_mailer.default_url_options = { host: 'localhost', port: 3000, protocol: 'http' }
+  config.action_mailer.default_url_options = { host: 'localhost', port: 3000}
 
   # Mailcatcher config, start mailcatcher from console with 'mailcatcher'
   # Mailcatcher can be installed by gem install mailcatcher
-  config.action_mailer.delivery_method = :smtp
-  config.action_mailer.smtp_settings = { address: ENV.fetch("MAILCATCHER_ADDRESS", "localhost"), port: ENV.fetch("MAILCATCHER_PORT", 1025) }
+  #config.action_mailer.delivery_method = :smtp
+  #config.action_mailer.smtp_settings = { address: ENV.fetch("MAILCATCHER_ADDRESS", "localhost"), port: ENV.fetch("MAILCATCHER_PORT", 1025) }
 
   # Raises error for missing translations
   # config.action_view.raise_on_missing_translations = true
diff --git a/config/locales/de.yml b/config/locales/de.yml
index 7b50fca7..113df2f7 100644
--- a/config/locales/de.yml
+++ b/config/locales/de.yml
@@ -101,6 +101,7 @@ de:
           actions_for_all: Aktion für alle ausführen
           delete: Rechnung löschen
           create_cumulative_invoice: Kumulative Rechnung erstellen
+          confirm_send_all: Möchtest Du wirklich diese Bestellgruppenrechnungen an %{ordergroups} versenden?
           combine: Rechnungen zusammenfassen
           download: Rechnung herunterladen
           download_all_zip: Alle Rechnungen herunterladen (zip)
@@ -111,6 +112,8 @@ de:
           ordergroup: Bestellgruppe
           paid: Bezahlt
           not_paid: Nicht Bezahlt
+          send_all_by_email: Alle Rechnungen versenden
+          send_all_success: Rechnungen erfolgreich versendet
           sepa_downloaded: SEPA exportiert
           sepa_not_downloaded: SEPA nicht exportiert
           sepa_not_ready:
@@ -195,6 +198,9 @@ de:
         last_user_activity: Zuletzt aktiv
         name: Name
         user_tokens: Mitglieder
+      ordergroup_invoice:
+        name: Bestellgruppenrechnung
+        email_sent: versendet am
       sepa_account_holder:
         bic: BIC
         holder:  SEPA Kontoinhaber*in
@@ -1393,6 +1399,15 @@ de:
         Im Anhang befindet sich daher eure Rechnung.
 
         Viele Grüße von %{foodcoop}
+    ordergroup_invoice:
+      subject: Bestellgruppenrechnung für %{group} bei %{supplier}
+      text: |
+        Liebe Bestellgruppe %{group},
+
+        Die Sammelbestellung bei %{supplier} wurde soeben abgerechnet und für die jeweiligen Bestellgruppen Rechnungen angelegt.
+        Im Anhang befindet sich daher eure Rechnung.
+
+        Viele Grüße von %{foodcoop}
     invite:
       subject: Einladung in die Foodcoop
       text: |
diff --git a/config/locales/en.yml b/config/locales/en.yml
index ae1f3cc5..742dc116 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -91,7 +91,7 @@ en:
         total_price: Sum
         unit_price: Price/Unit
       group_order_invoice:
-        name: Group order invoice
+        name: group-order-invoice
         sequence_type:
           FRST: "First Direct Debit"
           RCUR: "Recurring Direct Debit"
@@ -101,6 +101,7 @@ en:
           actions_for_all: Actions for all group orders
           create_cumulative_invoice: create cumulative invoice
           combine: combine invoices
+          confirm_send_all: Are you sure you want to send these ordergroup invoices to %{ordergroups}?
           delete: delete invoice
           download: download invoice
           download_all_zip: download all invoices as zip
@@ -111,6 +112,8 @@ en:
           ordergroup: Ordergroup
           paid: paid
           not_paid: unpaid
+          send_all_by_email: send all invoices
+          send_all_success: Invoices were sent to all ordergroups
           sepa_downloaded: SEPA exported
           sepa_not_downloaded: SEPA not exported
           sepa_not_ready: Configurations for SEPA are missing in Admin->Settings->Finances
@@ -194,6 +197,9 @@ en:
         last_user_activity: Last activity
         name: Name
         user_tokens: Members
+      ordergroup_invoice:
+        name: ordergroup-invoice
+        email_sent: Email sent at
       stock_article:
         available: Available
         price: Price
@@ -1358,7 +1364,16 @@ en:
       header: "%{user} wrote at %{date}:"
       subject: Feedback for Foodsoft
     group_order_invoice:
-      subject: Order group invoice for %{group} at %{supplier}
+      subject: Group order invoice for %{group} at %{supplier}
+      text: |
+        Dear order group %{group},
+
+        The collective order at %{supplier} has just been settled and invoices have been created for the respective order groups.
+        Attached you will find your invoice.
+
+        Best regards from %{foodcoop}
+    ordergroup_invoice:
+      subject: Group order invoice for %{group} at %{supplier}
       text: |
         Dear order group %{group},
 
diff --git a/config/routes.rb b/config/routes.rb
index 9d839c04..d1c9a160 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -2,6 +2,11 @@
 Rails.application.routes.draw do
   mount Rswag::Ui::Engine => '/api-docs'
   mount Rswag::Api::Engine => '/api-docs'
+
+  if Rails.env.development?
+    mount LetterOpenerWeb::Engine, at: "/letter_opener"
+  end
+  
   get 'order_comments/new'
 
   get 'comments/new'
@@ -152,7 +157,8 @@ Rails.application.routes.draw do
     post 'finance/group_order_invoice', to: 'group_order_invoices#create_multiple'
 
     get 'orders/:order_id/group_order_invoices/download_all', to: 'group_order_invoices#download_all', as: 'download_all_group_order_invoices'
-    get 'multi_orders/:multi_order_id/group_order_invoices/download_all', to: 'ordergroup_invoices#download_all', as: 'download_all_ordergroup_invoices'
+    get 'multi_orders/:multi_order_id/ordergroup_invoices/download_all', to: 'ordergroup_invoices#download_all', as: 'download_all_ordergroup_invoices'
+    post 'multi_orders/:multi_order_id/ordergroup_invoices/send_all', to: 'ordergroup_invoices#send_all', as: 'send_all_ordergroup_invoices'
 
     resources :ordergroup_invoices do
       member do
diff --git a/db/migrate/20250521134157_add_email_sent_to_ordergroup_invoice.rb b/db/migrate/20250521134157_add_email_sent_to_ordergroup_invoice.rb
new file mode 100644
index 00000000..5b369e85
--- /dev/null
+++ b/db/migrate/20250521134157_add_email_sent_to_ordergroup_invoice.rb
@@ -0,0 +1,5 @@
+class AddEmailSentToOrdergroupInvoice < ActiveRecord::Migration[7.0]
+  def change
+    add_column :ordergroup_invoices, :email_sent_at, :datetime
+  end
+end
diff --git a/db/routes.rb b/db/routes.rb
index e0c41b48..efde401b 100644
--- a/db/routes.rb
+++ b/db/routes.rb
@@ -162,6 +162,7 @@ Rails.application.routes.draw do
       end
       collection do
         get :download_within_date
+        get :send_all
         patch :select_all_sepa_sequence_type
         patch :toggle_all_sepa_downloaded
         patch :toggle_all_paid
diff --git a/db/schema.rb b/db/schema.rb
index 51a2ac73..e6d9fd05 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[7.0].define(version: 2025_05_16_104953) do
+ActiveRecord::Schema[7.0].define(version: 2025_05_21_134157) do
   create_table "action_text_rich_texts", charset: "utf8mb4", collation: "utf8mb4_general_ci", force: :cascade do |t|
     t.string "name", null: false
     t.text "body", size: :long
@@ -407,6 +407,7 @@ ActiveRecord::Schema[7.0].define(version: 2025_05_16_104953) do
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
     t.integer "multi_group_order_id"
+    t.datetime "email_sent_at"
     t.index ["multi_group_order_id"], name: "index_ordergroup_invoices_on_multi_group_order_id"
   end
 
diff --git a/db/seeds.rb b/db/seeds.rb
index 37a996ff..d34f28db 100644
--- a/db/seeds.rb
+++ b/db/seeds.rb
@@ -1,4 +1,4 @@
 # default seed is minimal
-require Rails.root.join('db/seeds/minimal.seeds.rb')
+require Rails.root.join('db/seeds/demo.seeds.rb')
 
 # to generate new seeds, use the seed_dumper gem
diff --git a/spec/factories/group_order.rb b/spec/factories/group_order.rb
index d62172ea..561edc11 100644
--- a/spec/factories/group_order.rb
+++ b/spec/factories/group_order.rb
@@ -5,5 +5,6 @@ FactoryBot.define do
   factory :group_order do
     ordergroup { create(:user, groups: [FactoryBot.create(:ordergroup)]).ordergroup }
     updated_by { create(:user) }
+    order
   end
 end
diff --git a/spec/factories/multi_group_order.rb b/spec/factories/multi_group_order.rb
new file mode 100644
index 00000000..0ca0f023
--- /dev/null
+++ b/spec/factories/multi_group_order.rb
@@ -0,0 +1,8 @@
+require 'factory_bot'
+
+FactoryBot.define do
+  factory :multi_group_order do
+    group_orders { [create(:group_order)] }
+    association :multi_order
+  end
+end
diff --git a/spec/factories/multi_order.rb b/spec/factories/multi_order.rb
new file mode 100644
index 00000000..f7814c68
--- /dev/null
+++ b/spec/factories/multi_order.rb
@@ -0,0 +1,21 @@
+require 'factory_bot'
+
+FactoryBot.define do
+  factory :multi_order do
+    transient do
+      orders { [create(:order, state: 'closed')] }
+    end
+
+    after(:build) do |multi_order, evaluator|
+      # Assign orders before validation so custom validations can see them
+      multi_order.orders = evaluator.orders
+    end
+
+    after(:create) do |multi_order, _evaluator|
+      # Persist the relationship by updating the orders (if needed)
+      multi_order.orders.each do |order|
+        order.update!(multi_order: multi_order)
+      end
+    end
+  end
+end
diff --git a/spec/factories/ordergroup_invoice.rb b/spec/factories/ordergroup_invoice.rb
new file mode 100644
index 00000000..c8b85ae7
--- /dev/null
+++ b/spec/factories/ordergroup_invoice.rb
@@ -0,0 +1,8 @@
+require 'factory_bot'
+
+FactoryBot.define do
+  factory :ordergroup_invoice do
+    multi_group_order { create :multi_group_order }
+    after(:build) { |ogi| ogi.init }
+  end
+end
diff --git a/spec/integration/multi_order_spec.rb b/spec/integration/multi_order_spec.rb
new file mode 100644
index 00000000..cc0fa783
--- /dev/null
+++ b/spec/integration/multi_order_spec.rb
@@ -0,0 +1,82 @@
+require_relative '../spec_helper'
+
+feature MultiOrder, type: :feature, js: true do
+  let(:admin) { create :user, groups: [create(:workgroup, role_finance: true), create(:ordergroup, name: "AdminOrders")] }
+  let(:user) { create :user, groups: [create(:ordergroup)] }
+
+  let(:article) { create :article, unit_quantity: 4 }
+  let(:article1) { create :article, unit_quantity: 2 }
+  let(:order) { create :order, supplier: article.supplier, article_ids: [article.id], ends: Time.now } 
+  let(:order1) { create :order, supplier: article1.supplier, article_ids: [article1.id], ends: Time.now } 
+
+  let(:go) { create :group_order, order: order, ordergroup: user.ordergroup}
+  let(:go1) { create :group_order, order: order1, ordergroup: admin.ordergroup}
+
+  let(:oa) { order.order_articles.find_by_article_id(article.id) }
+  let(:oa1) { order1.order_articles.find_by_article_id(article1.id) }
+  let(:ftt) { create :financial_transaction_type }
+
+  let(:goa) { create :group_order_article, group_order: go, order_article: oa }
+  let(:goa1) { create :group_order_article, group_order: go1, order_article: oa1 }
+
+  include ActiveJob::TestHelper
+
+  before do
+    login admin
+    goa.update_quantities 2, 0
+    goa1.update_quantities 2, 0
+    oa.update_results!
+    oa1.update_results!
+    FoodsoftConfig[:contact][:tax_number] = 12_345_678
+    order.update!(state: 'closed')
+    order1.update!(state: 'closed')
+  end
+
+  after { clear_enqueued_jobs }
+
+  # first ensure theres multiple orders and the check box to combine them to a multiorder
+
+  it 'shows the elements to combine orders' do
+    visit finance_order_index_path
+    expect(page).to have_css("#order_#{order.id}_combine")
+    expect(page).to have_css("#order_#{order1.id}_combine")
+    expect(page).to have_css(".merge-orders-btn")
+  end
+
+  it 'cannot combine orders when orders are not closed' do
+    order.update!(state: 'finished')
+    visit finance_order_index_path
+    expect(page).to have_css("#order_#{order.id}_combine")
+    expect(page).to have_css("#order_#{order1.id}_combine")
+    expect(page).to have_css(".merge-orders-btn")
+    # check the checkboxes and click the button
+    check("order_#{order.id}_combine")
+    check("order_#{order1.id}_combine")
+    click_link_or_button 'Zusammenführen'
+    expect(page).to have_content('Die Bestellung ist bereits Teil einer Multi-Bestellung oder ist noch nicht abgeschlossen.')
+  end
+
+  it 'cannot combine orders when group_orders already have an invoice' do
+    group_order_invoice = create(:group_order_invoice, group_order: go)
+    visit finance_order_index_path
+    expect(page).to have_css("#order_#{order.id}_combine")
+    expect(page).to have_css("#order_#{order1.id}_combine")
+    expect(page).to have_css(".merge-orders-btn")
+    # check the checkboxes and click the button
+    check("order_#{order.id}_combine")
+    check("order_#{order1.id}_combine")
+    click_link_or_button 'Zusammenführen'
+    expect(page).to have_content('Zusammenführen nicht möglich. Es gibt bereits Rechnungen für einige der Bestellgruppen.')
+  end
+
+  it 'combines orders into multi_order' do
+    visit finance_order_index_path
+    expect(MultiOrder.count).to eq(0)
+    check("order_#{order.id}_combine")
+    check("order_#{order1.id}_combine")
+    click_link_or_button 'Zusammenführen'
+    sleep 2
+    expect(page).to have_content("Multi Bestellung für #{MultiOrder.last.name} erstellt")
+    expect(MultiOrder.count).to eq(1)
+  end
+end
diff --git a/spec/integration/ordergroup_invoice_spec.rb b/spec/integration/ordergroup_invoice_spec.rb
new file mode 100644
index 00000000..3f07521c
--- /dev/null
+++ b/spec/integration/ordergroup_invoice_spec.rb
@@ -0,0 +1,131 @@
+require_relative '../spec_helper'
+
+feature OrdergroupInvoice, type: :feature, js: true do
+  let(:admin) { create :user, groups: [create(:workgroup, role_finance: true), create(:ordergroup, name: "AdminOrders")] }
+  let(:user) { create :user, groups: [create(:ordergroup)] }
+
+  let(:article) { create :article, unit_quantity: 4 }
+  let(:article1) { create :article, unit_quantity: 2 }
+  let(:order) { create :order, supplier: article.supplier, article_ids: [article.id], ends: Time.now } 
+  let(:order1) { create :order, supplier: article1.supplier, article_ids: [article1.id], ends: Time.now } 
+
+  let(:go) { create :group_order, order: order, ordergroup: user.ordergroup}
+  let(:go1) { create :group_order, order: order1, ordergroup: admin.ordergroup}
+
+  let(:oa) { order.order_articles.find_by_article_id(article.id) }
+  let(:oa1) { order1.order_articles.find_by_article_id(article1.id) }
+  let(:ftt) { create :financial_transaction_type }
+
+  let(:goa) { create :group_order_article, group_order: go, order_article: oa }
+  let(:goa1) { create :group_order_article, group_order: go1, order_article: oa1 }
+
+  include ActiveJob::TestHelper
+
+  before do
+    login admin
+    goa.update_quantities 2, 0
+    goa1.update_quantities 2, 0
+    oa.update_results!
+    oa1.update_results!
+    FoodsoftConfig[:contact][:tax_number] = 12_345_678
+    order.update!(state: 'closed')
+    order1.update!(state: 'closed')
+  end
+
+  after { clear_enqueued_jobs }
+
+  # first ensure theres multiple orders and the check box to combine them to a multiorder
+
+  it 'shows the elements to combine orders' do
+    visit finance_order_index_path
+    expect(page).to have_css("#order_#{order.id}_combine")
+    expect(page).to have_css("#order_#{order1.id}_combine")
+    expect(page).to have_css(".merge-orders-btn")
+  end
+
+  it 'cannot combine orders when orders are not closed' do
+    order.update!(state: 'finished')
+    visit finance_order_index_path
+    expect(page).to have_css("#order_#{order.id}_combine")
+    expect(page).to have_css("#order_#{order1.id}_combine")
+    expect(page).to have_css(".merge-orders-btn")
+    # check the checkboxes and click the button
+    check("order_#{order.id}_combine")
+    check("order_#{order1.id}_combine")
+    click_link_or_button 'Zusammenführen'
+    expect(page).to have_content('Die Bestellung ist bereits Teil einer Multi-Bestellung oder ist noch nicht abgeschlossen.')
+  end
+
+  it 'cannot combine orders when group_orders already have an invoice' do
+    group_order_invoice = create(:group_order_invoice, group_order: go)
+    visit finance_order_index_path
+    expect(page).to have_css("#order_#{order.id}_combine")
+    expect(page).to have_css("#order_#{order1.id}_combine")
+    expect(page).to have_css(".merge-orders-btn")
+    # check the checkboxes and click the button
+    check("order_#{order.id}_combine")
+    check("order_#{order1.id}_combine")
+    click_link_or_button 'Zusammenführen'
+    expect(page).to have_content('Zusammenführen nicht möglich. Es gibt bereits Rechnungen für einige der Bestellgruppen.')
+  end
+
+  it 'can generate multiple ordergroup invoice' do
+    multi_order = create(:multi_order, orders: [order, order1])
+    visit finance_order_index_path
+    expect(page).to have_selector(:link_or_button, "Multi Bestellung auflösen")
+    click_link_or_button 'Toggle details'
+    expect(page).to have_selector(:link_or_button, I18n.t('activerecord.attributes.group_order_invoice.links.generate_with_date'))
+    click_link_or_button I18n.t('activerecord.attributes.group_order_invoice.links.generate_with_date')
+    sleep 1
+    expect(OrdergroupInvoice.all.count).to eq(2)
+  end
+
+  it 'can generate single ordergroup invoice' do
+    multi_order = create(:multi_order, orders: [order, order1])
+    visit finance_order_index_path
+    expect(page).to have_selector(:link_or_button, "Multi Bestellung auflösen")
+    click_link_or_button 'Toggle details'
+    expect(page).to have_selector(:link_or_button, I18n.t('activerecord.attributes.group_order_invoice.links.generate'))
+    first(:link_or_button, I18n.t('activerecord.attributes.group_order_invoice.links.generate')).click
+    sleep 1
+    expect(OrdergroupInvoice.all.count).to eq(1)
+  end
+  it 'cannot toggel details when config wrong' do
+    FoodsoftConfig[:contact][:tax_number] = nil
+    multi_order = create(:multi_order, orders: [order, order1])
+    visit finance_order_index_path
+    expect(page).not_to have_selector(:link_or_button, 'Toggle details')
+  end
+  
+  it 'cannot destroy multi_order if invoice attached' do
+    multi_order = create(:multi_order, orders: [order, order1])
+    visit finance_order_index_path
+    expect(page).to have_selector(:link_or_button, "Multi Bestellung auflösen")
+    click_link_or_button 'Toggle details'
+    expect(page).to have_selector(:link_or_button, I18n.t('activerecord.attributes.group_order_invoice.links.generate'))
+    sleep 1
+    first(:link_or_button, I18n.t('activerecord.attributes.group_order_invoice.links.generate')).click
+    sleep 1
+    expect(OrdergroupInvoice.all.count).to eq(1)
+    click_link_or_button 'Multi Bestellung auflösen'
+    expect(page).to have_content("Lösche erst die Rechnungen")
+  end
+
+  it 'can toggle elements for ordergroup invoice' do
+    multi_order = create(:multi_order, orders: [order, order1])
+    visit finance_order_index_path
+    expect(page).to have_selector(:link_or_button, "Multi Bestellung auflösen")
+    click_link_or_button 'Toggle details'
+    expect(page).to have_selector(:link_or_button, I18n.t('activerecord.attributes.group_order_invoice.links.generate_with_date'))
+    click_link_or_button I18n.t('activerecord.attributes.group_order_invoice.links.generate_with_date')
+    sleep 1
+    expect(OrdergroupInvoice.all.count).to eq(2)
+    check("sepa_downloaded_all_multi_#{multi_order.id}")
+    sleep 1
+    expect(page).to have_checked_field("sepa_downloaded_multi_#{OrdergroupInvoice.last.id}")
+    expect(page).to have_checked_field("sepa_downloaded_multi_#{OrdergroupInvoice.first.id}")
+    check("paid_all_multi_#{multi_order.id}")
+    expect(page).to have_checked_field("paid_multi_#{OrdergroupInvoice.first.id}")
+    expect(page).to have_checked_field("paid_multi_#{OrdergroupInvoice.last.id}")
+  end
+end
diff --git a/spec/models/group_order_invoice_spec.rb b/spec/models/group_order_invoice_spec.rb
index 24bfcf7e..e2349838 100644
--- a/spec/models/group_order_invoice_spec.rb
+++ b/spec/models/group_order_invoice_spec.rb
@@ -43,7 +43,7 @@ describe GroupOrderInvoice do
 
     it 'fails to create if group_order_id is used multiple times for creation' do
       expect(goi1.group_order.id).to eq(group_order.id)
-      expect { goi2 }.to raise_error(ActiveRecord::RecordNotUnique)
+      expect { goi2 }.to raise_error(ActiveRecord::RecordInvalid)
     end
 
     it 'creates two different group order invoice with different invoice_numbers' do
diff --git a/spec/models/multi_group_order_spec.rb b/spec/models/multi_group_order_spec.rb
new file mode 100644
index 00000000..58250750
--- /dev/null
+++ b/spec/models/multi_group_order_spec.rb
@@ -0,0 +1,31 @@
+require_relative '../spec_helper'
+describe MultiGroupOrder do
+  let(:admin) { create :user, groups: [create(:workgroup, role_finance: true), create(:ordergroup, name: "AdminOrders")] }
+  let(:user) { create :user, groups: [create(:ordergroup)] }
+  
+  let(:article1) { create :article, unit_quantity: 1 }
+  let(:article2) { create :article, unit_quantity: 3 }
+    
+  context 'does not generate Multi Group Order without valid multi_order' do
+    it 'when orders are not closed' do
+      order1 = create :order, multi_order: nil
+      order2 = create :order, multi_order: nil
+      group_order1 = create :group_order, ordergroup: user.ordergroup, order: order1
+      group_order2 = create :group_order, ordergroup: user.ordergroup, order: order2
+      expect { create(:multi_order, orders:[order1, order2]) }.to raise_error(ActiveRecord::RecordInvalid)
+      expect(MultiGroupOrder.count).to eq(0)
+    end
+  end
+  context 'Multi Group Order is created by MultiOrder' do
+    it 'when orders are closed' do
+      order1 = create :order, multi_order: nil
+      order2 = create :order, multi_order: nil
+      group_order1 = create :group_order, ordergroup: user.ordergroup, order: order1
+      group_order2 = create :group_order, ordergroup: user.ordergroup, order: order2
+      order1.update!(state: 'closed')
+      order2.update!(state: 'closed')
+      multi_order = create(:multi_order, orders: [order1, order2])
+      expect(MultiGroupOrder.count).to eq(1)
+    end
+  end
+end
\ No newline at end of file
diff --git a/spec/models/multi_order_spec.rb b/spec/models/multi_order_spec.rb
new file mode 100644
index 00000000..c96c8128
--- /dev/null
+++ b/spec/models/multi_order_spec.rb
@@ -0,0 +1,68 @@
+require_relative '../spec_helper'
+describe MultiOrder do
+  let(:admin) { create :user, groups: [create(:workgroup, role_finance: true), create(:ordergroup, name: "AdminOrders")] }
+  let(:user) { create :user, groups: [create(:ordergroup)] }
+
+  let(:article1) { create :article, unit_quantity: 1 }
+  let(:article2) { create :article, unit_quantity: 3 }
+
+  context 'does not generate Multi Order' do
+    let(:order1) { create :order }
+    let(:order2) { create :order}
+    let!(:group_order1) { create :group_order, ordergroup: user.ordergroup, order: order1 }
+    let!(:group_order2) { create :group_order, ordergroup: user.ordergroup, order: order2 }
+    let!(:group_order3) { create :group_order, ordergroup: admin.ordergroup, order: order1 }
+  
+    before do
+      order1.update!(state: 'open')
+      order2.update!(state: 'open')
+      FoodsoftConfig[:contact][:tax_number] = 123_457_8
+    end
+  
+    it 'when orders are not closed' do
+      expect { create(:multi_order, orders: [order1]) }.to raise_error(ActiveRecord::RecordInvalid)
+    end
+
+    it 'when orders are not finished' do
+      expect { create(:multi_order, orders: [order2]) }.to raise_error(ActiveRecord::RecordInvalid)
+    end
+
+    
+    it 'when group order invoices are present' do
+      order1.update!(state: 'closed')
+      order2.update!(state: 'closed')
+      group_order1.update!(group_order_invoice: create(:group_order_invoice))
+      group_order2.update!(group_order_invoice: create(:group_order_invoice))
+      expect { create(:multi_order, orders: [order1, order2]) }.to raise_error(ActiveRecord::RecordInvalid)
+    end
+  end
+
+  context 'generates Multi Order' do
+
+    let(:order3) { create :order, multi_order: nil }
+    let(:order4) { create :order, multi_order: nil }
+    let(:order5) { create :order, multi_order: nil }
+
+    let!(:group_order1) { create :group_order, ordergroup: user.ordergroup, order: order3 }
+    let!(:group_order2) { create :group_order, ordergroup: user.ordergroup, order: order4 }
+    let!(:group_order3) { create :group_order, ordergroup: admin.ordergroup, order: order5 }
+    let!(:group_order4) { create :group_order, ordergroup: admin.ordergroup, order: order4 }
+
+    before do
+      order3.update!(state: 'closed')
+      order4.update!(state: 'closed')
+      order5.update!(state: 'closed')
+    end
+
+    it 'when orders are closed' do
+      #as it is right now orders can be in multiple multi orders
+      # expect(create(:multi_order, orders: [order3])).to be_valid
+      expect(create(:multi_order, orders: [order3])).to be_valid
+    end
+
+    it 'when group order invoices are not present' do
+      multi_order2 = create(:multi_order, orders: [order3, order4])
+      expect(multi_order2).to be_valid
+    end
+  end
+end
\ No newline at end of file
diff --git a/spec/models/ordergroup_invoice_spec.rb b/spec/models/ordergroup_invoice_spec.rb
new file mode 100644
index 00000000..2eba7946
--- /dev/null
+++ b/spec/models/ordergroup_invoice_spec.rb
@@ -0,0 +1,60 @@
+require_relative '../spec_helper'
+
+describe OrdergroupInvoice do
+  # TODO: DO REAL TESTING!
+  let(:user) { create :user, groups: [create(:ordergroup)] }
+  let(:supplier) { create :supplier }
+  let(:article) { create :article, supplier: supplier }
+  let(:order) { create :order, state: 'closed' }
+  let(:group_order) { create :group_order, order: order, ordergroup: user.ordergroup }
+  let(:multi_group_order) { create :multi_group_order, multi_order: create(:multi_order, orders: [order]) }
+  
+  describe 'erroneous group order invoice' do
+    before do
+      order.update!(state: 'closed')
+    end
+    let(:ogi) do
+      build(:ordergroup_invoice, multi_group_order: multi_group_order).tap(&:init)
+    end    
+    it 'does not create group order invoice if tax_number not set' do
+      expect { ogi }.to raise_error(ActiveRecord::RecordInvalid, /.*/)
+    end
+  end
+
+  describe 'valid group order invoice' do
+    before do
+      FoodsoftConfig[:contact][:tax_number] = 123_457_8
+      order.update!(state: 'closed')
+    end
+    let(:multi_group_order1) { create :multi_group_order, multi_order: create(:multi_order, orders: [order]) }
+    let(:ogi) do
+      build(:ordergroup_invoice, multi_group_order: multi_group_order1).tap(&:init)
+    end
+    invoice_number1 = Time.now.strftime("%Y%m%d") + '0001'
+    invoice_number2 = Time.now.strftime("%Y%m%d") + '0002'
+
+    it 'creates group order invoice if tax_number is set' do
+      expect(ogi).to be_valid
+    end
+
+    it 'sets invoice_number according to date' do
+      number = Time.now.strftime("%Y%m%d") + '0001'
+      expect(odi1.invoice_number).to eq(number.to_i)
+    end
+
+    it 'fails to create if group_order_id is used multiple times for creation' do
+      expect(odi1.group_order.id).to eq(group_order.id)
+      expect { odi2 }.to raise_error(ActiveRecord::RecordInvalid)
+    end
+
+    it 'creates two different group order invoice with different invoice_numbers' do
+      expect(odi1.invoice_number).to eq(invoice_number1.to_i)
+      expect(goi3.invoice_number).to eq(invoice_number2.to_i)
+    end
+
+    it 'fails to create two different group order invoice with same invoice_numbers' do
+      odi1
+      expect { goi4 }.to raise_error(ActiveRecord::RecordInvalid)
+    end
+  end
+end
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index ec5e7a35..59a47b9a 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -19,6 +19,8 @@ end
 # in spec/support/ and its subdirectories.
 Dir[Rails.root.join('spec/support/**/*.rb')].each { |f| require f }
 
+ActiveRecord::Migration.maintain_test_schema!
+
 RSpec.configure do |config|
   # We use capybara with webkit, and need database_cleaner
   config.before do