diff --git a/.env.docker b/.env.docker
index 4505a0f2..501c3d9d 100644
--- a/.env.docker
+++ b/.env.docker
@@ -39,3 +39,9 @@ OPENNEBULA_PROTOCOL=http
 OPENNEBULA_DOMAIN=test_domain
 OPENNEBULA_PORT=2633
 OPENNEBULA_ENDPOINT=/RPC2
+
+# Create dummy pages/users on start (idempotent). Set to False to turn off;
+# remove existing dummy data with: docker compose exec web python manage.py seed_dummy_data --purge
+SEED_DUMMY_DATA=True
+# Leave empty to get a random password printed in the web log on first start
+DUMMY_ADMIN_PASSWORD=
diff --git a/start-web.sh b/start-web.sh
index 7a837d5f..dc2be8d0 100644
--- a/start-web.sh
+++ b/start-web.sh
@@ -18,4 +18,8 @@ for domain in json.loads(os.environ.get('UNGLEICH_SITE_CONFIGS') or '{}'):
     Site.objects.get_or_create(domain=domain, defaults={'name': domain})
 PYEOF
 
+if [ "${SEED_DUMMY_DATA:-False}" = "True" ]; then
+    python manage.py seed_dummy_data || echo 'seed_dummy_data failed, continuing'
+fi
+
 exec python manage.py runserver 0.0.0.0:8000
diff --git a/utils/management/__init__.py b/utils/management/__init__.py
new file mode 100644
index 00000000..e69de29b
diff --git a/utils/management/commands/__init__.py b/utils/management/commands/__init__.py
new file mode 100644
index 00000000..e69de29b
diff --git a/utils/management/commands/seed_dummy_data.py b/utils/management/commands/seed_dummy_data.py
new file mode 100644
index 00000000..54da70bf
--- /dev/null
+++ b/utils/management/commands/seed_dummy_data.py
@@ -0,0 +1,102 @@
+"""
+Creates dummy data for test environments so that every site shows something
+different, or (with --purge) removes exactly what this command created.
+
+Everything it creates is recognisable and self-contained:
+  - one published CMS page per site, with reverse_id "dummy-home"
+  - a dummy admin and a dummy customer, with the emails below
+so it can be removed at any time without touching other data.
+
+Run automatically on start-up when SEED_DUMMY_DATA=True (see start-web.sh).
+"""
+import json
+import os
+import random
+import string
+
+from cms.api import add_plugin, create_page
+from cms.models import Page
+from django.conf import settings
+from django.contrib.sites.models import Site
+from django.core.management.base import BaseCommand
+
+from membership.models import CustomUser
+
+REVERSE_ID = 'dummy-home'
+ADMIN_EMAIL = 'dummy-admin@example.com'
+CUSTOMER_EMAIL = 'dummy-customer@example.com'
+LANGUAGE = 'en-us'
+TEMPLATE = 'one_column.html'
+
+
+class Command(BaseCommand):
+    help = "Create (or, with --purge, remove) dummy data for test environments"
+
+    def add_arguments(self, parser):
+        parser.add_argument('--purge', action='store_true',
+                            help="remove the dummy data instead of creating it")
+
+    def handle(self, *args, **options):
+        if options['purge']:
+            self.purge()
+        else:
+            self.seed()
+
+    def purge(self):
+        pages = Page.objects.filter(reverse_id=REVERSE_ID)
+        count = pages.count()
+        for page in pages:
+            page.delete()
+        users = CustomUser.objects.filter(
+            email__in=[ADMIN_EMAIL, CUSTOMER_EMAIL]).delete()
+        self.stdout.write("Removed {} dummy pages and {} user rows".format(
+            count, users[0] if isinstance(users, tuple) else users))
+
+    def seed(self):
+        self.seed_users()
+        for domain in self.site_domains():
+            site = Site.objects.filter(domain=domain).first()
+            if site is None:
+                continue
+            self.seed_page(site)
+        self.stdout.write("Dummy data ready")
+
+    def site_domains(self):
+        configs = json.loads(settings.UNGLEICH_SITE_CONFIGS or '{}')
+        return sorted(d for d in configs if ':' not in d)
+
+    def seed_users(self):
+        # built directly on the model: the user manager also creates LDAP
+        # accounts, which don't exist in the test environment
+        if not CustomUser.objects.filter(email=ADMIN_EMAIL).exists():
+            password = os.environ.get('DUMMY_ADMIN_PASSWORD') or ''.join(
+                random.SystemRandom().choice(string.ascii_letters + string.digits)
+                for _ in range(16))
+            admin = CustomUser(
+                email=ADMIN_EMAIL, name='Dummy Admin', validated=1,
+                is_admin=True, is_superuser=True)
+            admin.set_password(password)
+            admin.save()
+            self.stdout.write(
+                "Dummy admin: {} / {}".format(ADMIN_EMAIL, password))
+        if not CustomUser.objects.filter(email=CUSTOMER_EMAIL).exists():
+            customer = CustomUser(
+                email=CUSTOMER_EMAIL, name='Dummy Customer', validated=1)
+            customer.set_password('dummy-customer')
+            customer.save()
+
+    def seed_page(self, site):
+        if Page.objects.filter(reverse_id=REVERSE_ID, site=site).exists():
+            return
+        page = create_page(
+            '{} (dummy)'.format(site.domain), TEMPLATE, LANGUAGE,
+            slug='dummy-home', published=True, in_navigation=True,
+            site=site, reverse_id=REVERSE_ID)
+        placeholder = page.placeholders.first()
+        if placeholder is not None:
+            add_plugin(
+                placeholder, 'TextPlugin', LANGUAGE,
+                body='<h1>{0}</h1><p>Dummy page for {0}.</p>'.format(
+                    site.domain))
+            # publish again so the public copy contains the plugin
+            page.publish(LANGUAGE)