diff --git a/app/channels/application_cable/connection.rb b/app/channels/application_cable/connection.rb
new file mode 100644
index 00000000..98302857
--- /dev/null
+++ b/app/channels/application_cable/connection.rb
@@ -0,0 +1,36 @@
+# frozen_string_literal: true
+
+module ApplicationCable
+  class Connection < ActionCable::Connection::Base
+    # Authenticate via auth_token (same mechanism used in ApplicationController#authenticate_employee!)
+    # Clients should pass ?auth_token=TOKEN when connecting to the WebSocket.
+    identified_by :current_user, :current_entity_type
+
+    def connect
+      token = request.params[:auth_token].presence
+      reject_unauthorized_connection unless token
+
+      if (employee = Employee.find_by_authentication_token(token))
+        self.current_user = employee
+        self.current_entity_type = :employee
+      elsif (user = User.find_by_authentication_token(token))
+        self.current_user = user
+        self.current_entity_type = :user
+      elsif (supplier = Supplier.find_by_authentication_token(token))
+        self.current_user = supplier
+        self.current_entity_type = :supplier
+      else
+        reject_unauthorized_connection
+      end
+    end
+
+    # Allow subscribing to the entity's own channel
+    def subscribe_to_self
+      case current_entity_type
+      when :user     then "user_#{current_user.id}"
+      when :supplier then "supplier_#{current_user.id}"
+      when :employee then "employee_#{current_user.id}"
+      end
+    end
+  end
+end
diff --git a/app/channels/mozo_channel.rb b/app/channels/mozo_channel.rb
new file mode 100644
index 00000000..ab8d4bab
--- /dev/null
+++ b/app/channels/mozo_channel.rb
@@ -0,0 +1,41 @@
+# frozen_string_literal: true
+
+# Base channel. Streams are set up dynamically by clients subscribing
+# to their entity channel (user_123, supplier_456, etc.).
+#
+# The server broadcasts TO these channels via:
+#   ActionCable.server.broadcast("user_123", { event: "...", data: {...} })
+#
+# Clients connect and subscribe via:
+#   consumer.subscriptions.create({ channel: "MozoChannel", id: "user_123" })
+#
+class MozoChannel < ApplicationCable::Channel
+  def subscribed
+    stream_name = params[:id]
+    if authorized?(stream_name)
+      stream_from stream_name
+    else
+      reject
+    end
+  end
+
+  def unsubscribed
+    # cleanup
+  end
+
+  private
+
+  def authorized?(stream_name)
+    prefix, id = stream_name.to_s.split('_', 2)
+    case prefix
+    when 'user'
+      connection.current_entity_type == :user && connection.current_user.id.to_s == id
+    when 'supplier'
+      connection.current_entity_type == :supplier && connection.current_user.id.to_s == id
+    when 'employee'
+      connection.current_entity_type == :employee && connection.current_user.id.to_s == id
+    else
+      false
+    end
+  end
+end
diff --git a/app/models/concerns/broadcastable.rb b/app/models/concerns/broadcastable.rb
new file mode 100644
index 00000000..a2b89113
--- /dev/null
+++ b/app/models/concerns/broadcastable.rb
@@ -0,0 +1,29 @@
+# frozen_string_literal: true
+
+# Include this in any model that needs to broadcast events to users/suppliers.
+#
+# Replaces the old model_broadcast.rb initializer which monkey-patched
+# SimplyStored::Couch and created ApplicationController.new per broadcast
+# (memory-unsafe, no request context, to be removed once all callers migrate).
+#
+# Usage:
+#   class List < ApplicationRecord
+#     include Broadcastable
+#
+#     def close!
+#       broadcast_user(user.id, 'list_closed', { id: id })
+#       broadcast_supplier(supplier_id, 'list_closed', { id: id })
+#     end
+#   end
+#
+module Broadcastable
+  extend ActiveSupport::Concern
+
+  def broadcast_supplier(sid, event, data = {})
+    Mozo.broadcast_supplier(sid, event, data)
+  end
+
+  def broadcast_user(uid, event, data = {})
+    Mozo.broadcast_user(uid, event, data)
+  end
+end
diff --git a/config/cable.yml b/config/cable.yml
new file mode 100644
index 00000000..503efb4a
--- /dev/null
+++ b/config/cable.yml
@@ -0,0 +1,18 @@
+# ActionCable configuration for real-time broadcasting.
+#
+# Development/Test: async adapter (in-process, no external dependency).
+# Production: async is fine for single-server deployments.
+#   Switch to Redis (`redis://...`) if scaling to multiple Puma workers
+#   where broadcasts need to reach clients connected to different workers.
+#
+development:
+  adapter: async
+
+test:
+  adapter: test
+
+production:
+  adapter: async
+  # adapter: redis
+  # url: <%= ENV.fetch("REDIS_URL") { "redis://localhost:6379/1" } %>
+  # channel_prefix: mozo_backend_production
diff --git a/config/initializers/model_broadcast.rb b/config/initializers/model_broadcast.rb
index 68301256..bb505c41 100644
--- a/config/initializers/model_broadcast.rb
+++ b/config/initializers/model_broadcast.rb
@@ -1,12 +1,31 @@
-#TODO: this is really ugly, can cause memory leaks and much more bad stuff. We need a new broadcaster....
+# frozen_string_literal: true
+
+# Broadcast shim: provides broadcast_supplier / broadcast_user to all
+# SimplyStored::Couch models without requiring ApplicationController.new.
+#
+# PREVIOUSLY (dangerous):
+#   ApplicationController.new.send(:broadcast_supplier, *args)
+#   → leaked controller instances, no request lifecycle
+#
+# NOW:
+#   Delegates directly to Mozo.broadcast_supplier / Mozo.broadcast_user
+#   which uses Mozo.broadcaster (configurable: Faye or ActionCable).
+#
+# MIGRATION PATH:
+#   Models should `include Broadcastable` directly instead of relying
+#   on this monkey-patch. Once all models include Broadcastable, this
+#   initializer can be removed.
+#
 require 'simply_stored/couch'
+
 module ModelBroadcast
-  def broadcast_supplier(*args)
-    ApplicationController.new.send(:broadcast_supplier, *args)
+  def broadcast_supplier(sid, event, data = {})
+    Mozo.broadcast_supplier(sid, event, data)
   end
-  def broadcast_user(*args)
-    ApplicationController.new.send(:broadcast_user, *args)
+
+  def broadcast_user(uid, event, data = {})
+    Mozo.broadcast_user(uid, event, data)
   end
 end
+
 SimplyStored::Couch.send(:include, ModelBroadcast)
-#SimplyStored::Couch.send(:extend, ModelBroadcast) # this should never happen!!! 
diff --git a/config/routes.rb b/config/routes.rb
index 750d12e6..6128d1cc 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -1,5 +1,9 @@
 ALLOWED_LOCALES = /nl|de|fr|en|es/
 Mozo::Application.routes.draw do
+  # ActionCable WebSocket endpoint (replaces Faye at events.mozo.bar/faye)
+  # Clients connect via: wss://mozo.bar/cable?auth_token=TOKEN
+  mount ActionCable.server => '/cable'
+
   match '/.well-known/*rest', to: 'errors#not_found', via: :all
   match '/system/*rest',      to: 'errors#not_found', via: :all
   devise_for :users, controllers: {
diff --git a/docs/broadcasting-migration.md b/docs/broadcasting-migration.md
new file mode 100644
index 00000000..2ba2c972
--- /dev/null
+++ b/docs/broadcasting-migration.md
@@ -0,0 +1,89 @@
+# Broadcasting: Faye → ActionCable Migration Guide
+
+## Current state
+
+```
+Model (SimplyStored::Couch)
+  → ApplicationController.new.broadcast_user   # ⚠️ anti-pattern
+    → Mozo.broadcast_user
+      → Mozo::Broadcaster::Faye.new.broadcast  # HTTP POST to Faye
+        → Faye server (Thin, port 9296)
+          → WebSocket → browser clients
+```
+
+## Target state
+
+```
+Model (Broadcastable concern)
+  → Mozo.broadcast_user
+    → Mozo::Broadcaster::ActionCable.new.broadcast  # in-process async
+      → ActionCable (Rails built-in)
+        → WebSocket → browser clients
+```
+
+## What this branch adds
+
+| File | Purpose |
+|------|---------|
+| `lib/mozo/broadcaster/action_cable.rb` | Drop-in ActionCable broadcaster adapter |
+| `config/cable.yml` | ActionCable configuration (async for single-server) |
+| `app/channels/application_cable/connection.rb` | WebSocket auth via auth_token |
+| `app/channels/mozo_channel.rb` | Channel authorization for user/supplier/employee |
+| `app/models/concerns/broadcastable.rb` | Clean module for models (replaces old monkey-patch) |
+| `config/routes.rb` | Mounts `/cable` WebSocket endpoint |
+| `config/initializers/model_broadcast.rb` | Fixed: delegates to Mozo directly (no more `ApplicationController.new`) |
+
+## How to switch
+
+### 1. Server (one-line change)
+
+In `config/initializers/mozo_settings.rb`, change:
+
+```ruby
+# Mozo.broadcaster = Mozo::Broadcaster::Faye.new  # old
+Mozo.broadcaster = Mozo::Broadcaster::ActionCable.new  # new
+```
+
+### 2. Client (mozo-user / mozo-supplier)
+
+**Old Faye client (conceptual):**
+```js
+var client = new Faye.Client('https://events.mozo.bar/faye');
+client.subscribe('/user/123', function(msg) { ... });
+```
+
+**New ActionCable client:**
+```js
+// Using @rails/actioncable npm package
+import { createConsumer } from "@rails/actioncable";
+
+const consumer = createConsumer(
+  `wss://mozo.bar/cable?auth_token=${authToken}`
+);
+
+consumer.subscriptions.create(
+  { channel: "MozoChannel", id: "user_123" },
+  {
+    received(data) {
+      // data = { event: "list_closed", data: { id: 42 } }
+      handleEvent(data.event, data.data);
+    }
+  }
+);
+```
+
+### 3. Remove Faye
+
+Once stable:
+- Remove `gem 'faye'` from Gemfile
+- Remove `faye/` directory
+- Remove nginx `events.mozo.bar` vhost
+- Stop the Faye Thin process
+
+## Benefits
+
+- **No extra process** — ActionCable runs inside Puma
+- **Async** — `broadcast` is non-blocking
+- **Simpler deploys** — one less service to manage
+- **WebSocket native** — no long-polling fallback complexity
+- **Rails auth** — cookies/sessions work automatically
diff --git a/lib/mozo/broadcaster.rb b/lib/mozo/broadcaster.rb
index 1522a0b9..ed32275c 100644
--- a/lib/mozo/broadcaster.rb
+++ b/lib/mozo/broadcaster.rb
@@ -2,5 +2,6 @@ module Mozo
   module Broadcaster
     extend ActiveSupport::Autoload
     autoload :Faye
+    autoload :ActionCable
   end
 end
diff --git a/lib/mozo/broadcaster/action_cable.rb b/lib/mozo/broadcaster/action_cable.rb
new file mode 100644
index 00000000..2331490c
--- /dev/null
+++ b/lib/mozo/broadcaster/action_cable.rb
@@ -0,0 +1,51 @@
+# frozen_string_literal: true
+
+module Mozo
+  module Broadcaster
+    # Drop-in replacement for Mozo::Broadcaster::Faye that uses
+    # Rails' built-in ActionCable instead of an external Faye process.
+    #
+    # Benefits over Faye:
+    #   - Async by default (ActionCable.server.broadcast is non-blocking)
+    #   - No extra gem / process / port to manage
+    #   - Integrated with Rails authentication (cookies, sessions)
+    #   - WebSocket native (no long-polling fallback needed with modern browsers)
+    #
+    # Channel naming is kept compatible with the existing Faye convention:
+    #   /user/:uid    → user_<uid>
+    #   /supplier/:sid → supplier_<sid>
+    #
+    # To use:
+    #   Set Mozo.broadcaster = Mozo::Broadcaster::ActionCable.new
+    #   in config/initializers/mozo_settings.rb
+    #
+    class ActionCable
+      CHANNEL_PREFIX_REMAP = {
+        %r{^/user/(.+)$}     => 'user_\1',
+        %r{^/supplier/(.+)$} => 'supplier_\1'
+      }.freeze
+
+      def broadcast(message)
+        channel = message[:channel] || message['channel']
+        data    = message[:data]    || message['data']
+
+        remapped = remap_channel(channel)
+        return unless remapped
+
+        ::ActionCable.server.broadcast(remapped, data)
+      rescue => e
+        Rails.logger.error("[ACTION_CABLE][ERROR] #{e.message}")
+      end
+
+      private
+
+      def remap_channel(channel)
+        CHANNEL_PREFIX_REMAP.each do |pattern, replacement|
+          return channel.sub(pattern, replacement) if channel.match?(pattern)
+        end
+        Rails.logger.warn("[ACTION_CABLE] Unknown channel format: #{channel}")
+        nil
+      end
+    end
+  end
+end