diff --git a/src/pretix/base/__init__.py b/src/pretix/base/__init__.py
index 48435281d9..13d6de6b37 100644
--- a/src/pretix/base/__init__.py
+++ b/src/pretix/base/__init__.py
@@ -8,7 +8,7 @@ class PretixBaseConfig(AppConfig):
     def ready(self):
         from . import exporter  # NOQA
         from . import payment  # NOQA
-        from .services import export, mail, tickets  # NOQA
+        from .services import export, mail, tickets, cart, orders  # NOQA
 
         try:
             from .celery import app as celery_app  # NOQA
diff --git a/src/pretix/base/payment.py b/src/pretix/base/payment.py
index 1d4025860e..582b026ce7 100644
--- a/src/pretix/base/payment.py
+++ b/src/pretix/base/payment.py
@@ -251,7 +251,7 @@ class BasePaymentProvider:
         """
         After the user confirmed his purchase, this method will be called to complete
         the payment process. This is the place to actually move the money, if applicable.
-        If you need any speical  behaviour,  you can return a string
+        If you need any special  behaviour,  you can return a string
         containing an URL the user will be redirected to. If you are done with your process
         you should return the user to the order's detail page.
 
diff --git a/src/pretix/base/services/cart.py b/src/pretix/base/services/cart.py
index bd854e55ec..5727548a49 100644
--- a/src/pretix/base/services/cart.py
+++ b/src/pretix/base/services/cart.py
@@ -1,5 +1,6 @@
 from datetime import timedelta
 
+from django.conf import settings
 from django.db.models import Q
 from django.utils.timezone import now
 from django.utils.translation import ugettext_lazy as _
@@ -16,7 +17,7 @@ class CartError(Exception):
 error_messages = {
     'busy': _('We were not able to process your request completely as the '
               'server was too busy. Please try again.'),
-    'empty': _('You did not select any items.'),
+    'empty': _('You did not select any products.'),
     'not_for_sale': _('You selected a product which is not available for sale.'),
     'unavailable': _('Some of the products you selected were no longer available. '
                      'Please see below for details.'),
@@ -128,6 +129,27 @@ def _add_items(event, items, session, expiry):
     return err
 
 
+def _add_items_to_cart(event: Event, items: list, session: str=None):
+    with event.lock():
+        _check_date(event)
+        existing = CartPosition.objects.current.filter(Q(session=session) & Q(event=event)).count()
+        if sum(i[2] for i in items) + existing > int(event.settings.max_items_per_order):
+            # TODO: i18n plurals
+            raise CartError(error_messages['max_items'] % event.settings.max_items_per_order)
+
+        expiry = now() + timedelta(minutes=event.settings.get('reservation_time', as_type=int))
+        _extend_existing(event, session, expiry)
+
+        expired = _re_add_expired_positions(items, event, session)
+        if not items:
+            raise CartError(error_messages['empty'])
+
+        err = _add_items(event, items, session, expiry)
+        _delete_expired(expired)
+        if err:
+            raise CartError(err)
+
+
 def add_items_to_cart(event: str, items: list, session: str=None):
     """
     Adds a list of items to a user's cart.
@@ -138,24 +160,7 @@ def add_items_to_cart(event: str, items: list, session: str=None):
     """
     event = Event.objects.current.get(identity=event)
     try:
-        with event.lock():
-            _check_date(event)
-            existing = CartPosition.objects.current.filter(Q(session=session) & Q(event=event)).count()
-            if sum(i[2] for i in items) + existing > int(event.settings.max_items_per_order):
-                # TODO: i18n plurals
-                raise CartError(error_messages['max_items'] % event.settings.max_items_per_order)
-
-            expiry = now() + timedelta(minutes=event.settings.get('reservation_time', as_type=int))
-            _extend_existing(event, session, expiry)
-
-            expired = _re_add_expired_positions(items, event, session)
-            if not items:
-                raise CartError(error_messages['empty'])
-
-            err = _add_items(event, items, session, expiry)
-            _delete_expired(expired)
-            if err:
-                raise CartError(err)
+        return _add_items_to_cart(event, items, session)
     except EventLock.LockTimeoutException:
         raise CartError(error_messages['busy'])
 
@@ -177,3 +182,17 @@ def remove_items_from_cart(event: str, items: list, session: str=None):
             cw &= Q(variation__isnull=True)
         for cp in CartPosition.objects.current.filter(cw).order_by("-price")[:cnt]:
             cp.delete()
+
+
+if settings.HAS_CELERY:
+    from pretix.celery import app
+
+    @app.task(bind=True, max_retries=5, default_retry_delay=2)
+    def add_items_to_cart_task(self, event: str, items: list, session: str):
+        event = Event.objects.current.get(identity=event)
+        try:
+            return _add_items_to_cart(event, items, session)
+        except EventLock.LockTimeoutException:
+            self.retry(exc=CartError(error_messages['busy']))
+
+    add_items_to_cart.task = add_items_to_cart_task
diff --git a/src/pretix/base/services/orders.py b/src/pretix/base/services/orders.py
index 2a629c2cf0..8502ce0ac1 100644
--- a/src/pretix/base/services/orders.py
+++ b/src/pretix/base/services/orders.py
@@ -1,13 +1,19 @@
 from datetime import datetime, timedelta
 
+from django.conf import settings
 from django.db import transaction
 from django.utils.timezone import now
 from django.utils.translation import ugettext_lazy as _
 
-from pretix.base.models import Event, EventLock, Order, OrderPosition, Quota
+from pretix.base.models import (
+    CartPosition, Event, EventLock, Order, OrderPosition, Quota,
+)
 from pretix.base.payment import BasePaymentProvider
+from pretix.base.services.cart import CartError
 from pretix.base.services.mail import mail
-from pretix.base.signals import order_paid, order_placed
+from pretix.base.signals import (
+    order_paid, order_placed, register_payment_providers,
+)
 from pretix.helpers.urls import build_absolute_uri
 
 error_messages = {
@@ -18,6 +24,7 @@ error_messages = {
     'price_changed': _('The price of some of the items in your cart has changed in the '
                        'meantime. Please see below for details.'),
     'max_items': _("You cannot select more than %s items per order"),
+    'internal': _("An internal error occured, please try again."),
     'busy': _('We were not able to process your request completely as the '
               'server was too busy. Please try again.'),
 }
@@ -85,7 +92,7 @@ def _check_date(event):
         raise OrderError(error_messages['ended'])
 
 
-def check_positions(event: Event, dt: datetime, positions: list):
+def _check_positions(event: Event, dt: datetime, positions: list):
     err = None
     _check_date(event)
 
@@ -130,41 +137,9 @@ def check_positions(event: Event, dt: datetime, positions: list):
         raise OrderError(err)
 
 
-def perform_order(event: Event, payment_provider: BasePaymentProvider, positions: list,
-                  email: str=None, locale: str=None):
-    dt = now()
-
-    try:
-        with event.lock():
-            check_positions(event, dt, positions)
-            order = place_order(event, email, positions, dt, payment_provider,
-                                locale=locale)
-            mail(
-                order.email, _('Your order: %(code)s') % {'code': order.code},
-                'pretixpresale/email/order_placed.txt',
-                {
-                    'order': order,
-                    'event': event,
-                    'url': build_absolute_uri('presale:event.order', kwargs={
-                        'event': event.slug,
-                        'organizer': event.organizer.slug,
-                        'order': order.code,
-                        'secret': order.secret
-                    }),
-                    'payment': payment_provider.order_pending_mail_render(order)
-                },
-                event, locale=order.locale
-            )
-            return order
-    except EventLock.LockTimeoutException:
-        # Is raised when there are too many threads asking for event locks and we were
-        # unable to get one
-        raise OrderError(error_messages['busy'])
-
-
 @transaction.atomic()
-def place_order(event: Event, email: str, positions: list, dt: datetime,
-                payment_provider: BasePaymentProvider, locale: str=None):
+def _create_order(event: Event, email: str, positions: list, dt: datetime,
+                  payment_provider: BasePaymentProvider, locale: str=None):
     total = sum([c.price for c in positions])
     payment_fee = payment_provider.calculate_fee(total)
     total += payment_fee
@@ -180,8 +155,72 @@ def place_order(event: Event, email: str, positions: list, dt: datetime,
         locale=locale,
         total=total,
         payment_fee=payment_fee,
-        payment_provider=payment_provider.identifier,
+        payment_provider=payment_provider.identifier
     )
     OrderPosition.transform_cart_positions(positions, order)
     order_placed.send(event, order=order)
     return order
+
+
+def _perform_order(event: Event, payment_provider: BasePaymentProvider, position_ids: list,
+                   email: str, locale: str):
+    event = Event.objects.current.get(identity=event)
+    responses = register_payment_providers.send(event)
+    pprov = None
+    for receiver, response in responses:
+        provider = response(event)
+        if provider.identifier == payment_provider:
+            pprov = provider
+    if not pprov:
+        raise OrderError(error_messages['internal'])
+
+    dt = now()
+    with event.lock():
+        positions = list(CartPosition.objects.current.filter(
+            identity__in=position_ids).select_related('item', 'variation'))
+        if len(position_ids) != len(positions):
+            raise OrderError(error_messages['internal'])
+        _check_positions(event, dt, positions)
+        order = _create_order(event, email, positions, dt, pprov,
+                              locale=locale)
+        mail(
+            order.email, _('Your order: %(code)s') % {'code': order.code},
+            'pretixpresale/email/order_placed.txt',
+            {
+                'order': order,
+                'event': event,
+                'url': build_absolute_uri('presale:event.order', kwargs={
+                    'event': event.slug,
+                    'organizer': event.organizer.slug,
+                    'order': order.code,
+                    'secret': order.secret
+                }),
+                'payment': pprov.order_pending_mail_render(order)
+            },
+            event, locale=order.locale
+        )
+        return order.identity
+
+
+def perform_order(event: str, payment_provider: str, positions: list,
+                  email: str=None, locale: str=None):
+    try:
+        return _perform_order(event, payment_provider, positions, email, locale)
+    except EventLock.LockTimeoutException:
+        # Is raised when there are too many threads asking for event locks and we were
+        # unable to get one
+        raise OrderError(error_messages['busy'])
+
+
+if settings.HAS_CELERY:
+    from pretix.celery import app
+
+    @app.task(bind=True, max_retries=5, default_retry_delay=2)
+    def perform_order_task(self, event: str, payment_provider: str, positions: list,
+                           email: str=None, locale: str=None):
+        try:
+            return _perform_order(event, payment_provider, positions, email, locale)
+        except EventLock.LockTimeoutException:
+            self.retry(exc=OrderError(error_messages['busy']))
+
+    perform_order.task = perform_order_task
diff --git a/src/pretix/plugins/paypal/payment.py b/src/pretix/plugins/paypal/payment.py
index 5f77f5ca93..711ef37b01 100644
--- a/src/pretix/plugins/paypal/payment.py
+++ b/src/pretix/plugins/paypal/payment.py
@@ -181,7 +181,6 @@ class Paypal(BasePaymentProvider):
 
         try:
             mark_order_paid(order, 'paypal', json.dumps(payment.to_dict()))
-            messages.success(request, _('We successfully received your payment. Thank you!'))
         except Quota.QuotaExceededException as e:
             messages.error(request, str(e))
         return None
diff --git a/src/pretix/plugins/paypal/views.py b/src/pretix/plugins/paypal/views.py
index 4165daeeb0..b79731ad40 100644
--- a/src/pretix/plugins/paypal/views.py
+++ b/src/pretix/plugins/paypal/views.py
@@ -23,9 +23,10 @@ def success(request):
         request.session['payment_paypal_payer'] = payer
         try:
             event = Event.objects.current.get(identity=request.session['payment_paypal_event'])
-            return redirect('presale:event.checkout.confirm',
+            return redirect('presale:event.checkout',
                             event=event.slug,
-                            organizer=event.organizer.slug)
+                            organizer=event.organizer.slug,
+                            step='confirm')
         except Event.DoesNotExist:
             pass  # TODO: Handle this
     else:
@@ -37,9 +38,10 @@ def abort(request):
     messages.error(request, _('It looks like you cancelled the PayPal payment'))
     try:
         event = Event.objects.current.get(identity=request.session['payment_paypal_event'])
-        return redirect('presale:event.checkout.payment',
+        return redirect('presale:event.checkout',
                         event=event.slug,
-                        organizer=event.organizer.slug)
+                        organizer=event.organizer.slug,
+                        step='payment')
     except Event.DoesNotExist:
         pass  # TODO: Handle this
 
@@ -104,4 +106,5 @@ def retry(request, order):
     return redirect('presale:event.order',
                     event=order.event.slug,
                     organizer=order.event.organizer.slug,
-                    order=order.code)
+                    order=order.code,
+                    secret=order.secret) + '?paid=yes'
diff --git a/src/pretix/plugins/stripe/payment.py b/src/pretix/plugins/stripe/payment.py
index c041f3d6df..74b8f0db48 100644
--- a/src/pretix/plugins/stripe/payment.py
+++ b/src/pretix/plugins/stripe/payment.py
@@ -116,7 +116,6 @@ class Stripe(BasePaymentProvider):
             if charge.status == 'succeeded' and charge.paid:
                 try:
                     mark_order_paid(order, 'stripe', str(charge))
-                    messages.success(request, _('We successfully received your payment. Thank you!'))
                 except Quota.QuotaExceededException as e:
                     messages.error(request, str(e))
             else:
diff --git a/src/pretix/plugins/stripe/signals.py b/src/pretix/plugins/stripe/signals.py
index e6c85b941a..70a6361a91 100644
--- a/src/pretix/plugins/stripe/signals.py
+++ b/src/pretix/plugins/stripe/signals.py
@@ -20,7 +20,7 @@ def html_head_presale(sender, request=None, **kwargs):
 
     provider = Stripe(sender)
     url = resolve(request.path_info)
-    if provider.is_enabled and ("checkout.payment" in url.url_name or "order.pay" in url.url_name):
+    if provider.is_enabled and ("checkout" in url.url_name or "order.pay" in url.url_name):
         template = get_template('pretixplugins/stripe/presale_head.html')
         ctx = Context({'event': sender, 'settings': provider.settings})
         return template.render(ctx)
diff --git a/src/pretix/presale/checkoutflow.py b/src/pretix/presale/checkoutflow.py
index 653e57cbc8..79ea409e37 100644
--- a/src/pretix/presale/checkoutflow.py
+++ b/src/pretix/presale/checkoutflow.py
@@ -1,3 +1,4 @@
+from django.conf import settings
 from django.contrib import messages
 from django.core.exceptions import ValidationError
 from django.core.urlresolvers import reverse
@@ -10,12 +11,13 @@ from django.utils.functional import cached_property
 from django.utils.translation import ugettext_lazy as _
 from django.views.generic.base import TemplateResponseMixin
 
-from pretix.base.models import CartPosition
+from pretix.base.models import CartPosition, Order
 from pretix.base.services.orders import OrderError, perform_order
 from pretix.base.signals import register_payment_providers
 from pretix.presale.forms.checkout import ContactForm
 from pretix.presale.signals import checkout_flow_steps
 from pretix.presale.views import CartMixin
+from pretix.presale.views.async import AsyncAction
 from pretix.presale.views.questions import QuestionsViewMixin
 
 
@@ -278,10 +280,11 @@ class PaymentStep(QuestionsViewMixin, CartMixin, TemplateFlowStep):
         return True
 
 
-class ConfirmStep(CartMixin, TemplateFlowStep):
+class ConfirmStep(CartMixin, AsyncAction, TemplateFlowStep):
     priority = 1001
     identifier = "confirm"
     template_name = "pretixpresale/event/checkout_confirm.html"
+    task = perform_order
 
     def is_applicable(self, request):
         return True
@@ -304,28 +307,47 @@ class ConfirmStep(CartMixin, TemplateFlowStep):
             if provider.identifier == self.request.session['payment']:
                 return provider
 
+    def get(self, request):
+        self.request = request
+        if 'async_id' in request.GET and settings.HAS_CELERY:
+            return self.get_result(request)
+        return TemplateFlowStep.get(self, request)
+
     def post(self, request):
         self.request = request
-        try:
-            order = perform_order(self.request.event, self.payment_provider, self.positions,
-                                  email=request.session.get('email', None),
-                                  locale=translation.get_language())
-        except OrderError as e:
-            messages.error(request, str(e))
-            return redirect(self.get_step_url())
-        else:
-            # Message is delivered via GET parameter
-            # messages.success(request, _('Your order has been placed.'))
-            resp = self.payment_provider.payment_perform(request, order)
-            return redirect(resp or self.get_order_url(order))
+        return self.do(self.request.event.identity, self.payment_provider.identifier,
+                       [p.identity for p in self.positions], request.session.get('email'),
+                       translation.get_language())
+
+    def get_success_message(self, value):
+        return None
+
+    def success(self, value):
+        # Message is delivered via GET parameter
+        # messages.success(request, _('Your order has been placed.'))
+        return redirect(self.get_success_url(value))
+
+    def get_success_url(self, value):
+        order = Order.objects.current.get(identity=value)
+        return self.get_order_url(order)
+
+    def get_error_message(self, exception):
+        if isinstance(exception, dict) and exception['exc_type'] == 'OrderError':
+            return exception['exc_message']
+        elif isinstance(exception, OrderError):
+            return str(exception)
+        return super().get_error_message(exception)
+
+    def get_error_url(self):
+        return self.get_step_url()
 
     def get_order_url(self, order):
-        return reverse('presale:event.order', kwargs={
+        return reverse('presale:event.order.pay.complete', kwargs={
             'event': self.request.event.slug,
             'organizer': self.request.event.organizer.slug,
             'order': order.code,
             'secret': order.secret
-        }) + '?thanks=yes'
+        })
 
 
 DEFAULT_FLOW = (
diff --git a/src/pretix/presale/templates/pretixpresale/event/base.html b/src/pretix/presale/templates/pretixpresale/event/base.html
index a14e060d67..9cb34db1ab 100644
--- a/src/pretix/presale/templates/pretixpresale/event/base.html
+++ b/src/pretix/presale/templates/pretixpresale/event/base.html
@@ -13,6 +13,7 @@
         <script type="text/javascript" src="{% static "js/jquery.formset.js" %}"></script>
         <script type="text/javascript" src="{% static "bootstrap/dist/js/bootstrap.js" %}"></script>
         <script type="text/javascript" src="{% static "pretixpresale/js/ui/main.js" %}"></script>
+        <script type="text/javascript" src="{% static "pretixpresale/js/ui/asynctask.js" %}"></script>
     {% endcompress %}
     {{ html_head|safe }}
     <meta name="viewport" content="width=device-width, initial-scale=1">
@@ -63,6 +64,16 @@
         {% endblocktrans %}
     {% endwith %}
 </footer>
+<script type="text/javascript">
+    var default_loading_message = '{% trans "We are processing your request…" %}';
+</script>
+<div id="loadingmodal">
+    <i class="fa fa-cog big-rotating-icon"></i>
+    <h1>{% trans "We are processing your request…" %}</h1>
+    <p>
+        {% trans "If this takes longer than a few minutes, please contact us." %}
+    </p>
+</div>
 {% compress js %}
     <script type="text/javascript" src="{% static "lightbox/js/lightbox.min.js" %}"></script>
 {% endcompress %}
diff --git a/src/pretix/presale/templates/pretixpresale/event/checkout_confirm.html b/src/pretix/presale/templates/pretixpresale/event/checkout_confirm.html
index 40879fc376..a16a0dad5d 100644
--- a/src/pretix/presale/templates/pretixpresale/event/checkout_confirm.html
+++ b/src/pretix/presale/templates/pretixpresale/event/checkout_confirm.html
@@ -5,7 +5,7 @@
 {% block content %}
     <h2>{% trans "Confirm order" %}</h2>
     <p>{% trans "Please review the details below and confirm your order." %}</p>
-    <form method="post">
+    <form method="post" data-asynctask>
         {% csrf_token %}
         <div class="panel panel-primary cart">
             <div class="panel-heading">
diff --git a/src/pretix/presale/templates/pretixpresale/event/fragment_cart.html b/src/pretix/presale/templates/pretixpresale/event/fragment_cart.html
index 6333c16335..235b797a04 100644
--- a/src/pretix/presale/templates/pretixpresale/event/fragment_cart.html
+++ b/src/pretix/presale/templates/pretixpresale/event/fragment_cart.html
@@ -37,7 +37,7 @@
             {{ line.count }}
             {% if editable %}
             <form action="{% url "presale:event.cart.add" event=event.slug organizer=event.organizer.slug %}"
-                method="post">
+                method="post" data-asynctask>
                 {% csrf_token %}
                 {% if line.variation %}
                     <input type="hidden" name="variation_{{ line.item.identity }}_{{ line.variation.identity }}"
diff --git a/src/pretix/presale/templates/pretixpresale/event/index.html b/src/pretix/presale/templates/pretixpresale/event/index.html
index 1c9cd90b74..e207a41111 100644
--- a/src/pretix/presale/templates/pretixpresale/event/index.html
+++ b/src/pretix/presale/templates/pretixpresale/event/index.html
@@ -50,7 +50,7 @@
         </div>
     {% endif %}
     {% if event.presale_is_running or event.settings.show_items_outside_presale_period %}
-        <form method="post"
+        <form method="post" data-asynctask
                 action="{% url "presale:event.cart.add" organizer=request.event.organizer.slug event=request.event.slug %}?next={{ request.path|urlencode }}">
             {% csrf_token %}
             {% for tup in items_by_category %}
diff --git a/src/pretix/presale/templates/pretixpresale/event/order.html b/src/pretix/presale/templates/pretixpresale/event/order.html
index 08bd7e0ebd..450933cc99 100644
--- a/src/pretix/presale/templates/pretixpresale/event/order.html
+++ b/src/pretix/presale/templates/pretixpresale/event/order.html
@@ -3,11 +3,16 @@
 {% load bootstrap3 %}
 {% block title %}{% trans "Order details" %}{% endblock %}
 {% block content %}
-    {% if "thanks" in request.GET %}
+    {% if "thanks" in request.GET or "paid" in request.GET %}
         <div class="thank-you">
             <span class="fa fa-check-circle"></span>
+
             <h2>{% trans "Thank you!" %}</h2>
-            <p>{% trans "Your order has been placed successfully. See below for details." %}</p>
+            {% if order.status != 'p' %}
+                <p>{% trans "Your order has been placed successfully. See below for details." %}</p>
+            {% else %}
+                <p>{% trans "We successfully received your payment. See below for details." %}</p>
+            {% endif %}
             <p>{% trans "We also sent you an email with a link to this page if you want to come back later." %}</p>
         </div>
     {% endif %}
@@ -18,7 +23,7 @@
         {% include "pretixpresale/event/fragment_order_status.html" with order=order class="pull-right" %}
         <div class="clearfix"></div>
     </h2>
-    {% if order.status == "n"  %}
+    {% if order.status == "n" %}
         <div class="panel panel-danger">
             <div class="panel-heading">
                 <h3 class="panel-title">
@@ -28,12 +33,14 @@
             <div class="panel-body">
                 {% if can_retry %}
                     <a href="{% url "presale:event.order.pay" organizer=request.event.organizer.slug event=request.event.slug secret=order.secret order=order.code %}"
-                       class="btn btn-primary pull-right"><i class="fa fa-money"></i> {% trans "Complete payment" %}</a>
+                            class="btn btn-primary pull-right"><i class="fa fa-money"></i> {% trans "Complete payment" %}
+                    </a>
                 {% endif %}
                 {{ payment }}
                 <strong>{% blocktrans trimmed with date=order.expires|date:"SHORT_DATE_FORMAT" %}
                     Please complete your payment before {{ date }}
                 {% endblocktrans %}</strong>
+
                 <div class="clearfix"></div>
             </div>
         </div>
@@ -88,7 +95,7 @@
             <div class="col-md-12 text-right">
                 <p>
                     <a href="{% url 'presale:event.order.cancel' event=request.event.slug organizer=request.event.organizer.slug secret=order.secret order=order.code %}"
-                       class="btn btn-danger">
+                            class="btn btn-danger">
                         <span class="fa fa-remove"></span>
                         {% trans "Cancel order" %}
                     </a>
diff --git a/src/pretix/presale/templates/pretixpresale/waiting.html b/src/pretix/presale/templates/pretixpresale/waiting.html
new file mode 100644
index 0000000000..b5b1fe8eef
--- /dev/null
+++ b/src/pretix/presale/templates/pretixpresale/waiting.html
@@ -0,0 +1,37 @@
+{% load compress %}
+{% load i18n %}
+{% load staticfiles %}
+<!DOCTYPE html>
+<html>
+<head>
+    <title>{{ settings.PRETIX_INSTANCE_NAME }}</title>
+    {% compress css %}
+        <link rel="stylesheet" type="text/less" href="{% static "pretixpresale/less/waiting.less" %}"/>
+    {% endcompress %}
+    {% compress js %}
+        <script type="text/javascript" src="{% static "jquery/js/jquery-2.1.1.min.js" %}"></script>
+    {% endcompress %}
+    <meta name="viewport" content="width=device-width, initial-scale=1">
+    <meta http-equiv="refresh" content="1">
+</head>
+<body>
+<div class="container">
+    <i class="fa fa-cog big-rotating-icon"></i>
+
+    <h1>{% trans "We are processing your request…" %}</h1>
+
+    <p>
+        {% trans "If this takes longer than a few minutes, please contact us." %}
+    </p>
+</div>
+<script type="text/javascript">
+    window.setInterval(function () {
+        $.get(location.href + '&ajax=1', function (data, status) {
+            if (data.ready && data.redirect) {
+                location.href = data.redirect;
+            }
+        }, 'json');
+    }, 2000);
+</script>
+</body>
+</html>
diff --git a/src/pretix/presale/urls.py b/src/pretix/presale/urls.py
index 2d7243d3ad..885ac7afa2 100644
--- a/src/pretix/presale/urls.py
+++ b/src/pretix/presale/urls.py
@@ -27,6 +27,9 @@ urlpatterns = [
         url(r'^order/(?P<order>[^/]+)/(?P<secret>[A-Za-z0-9]+)/pay/confirm$',
             pretix.presale.views.order.OrderPayDo.as_view(),
             name='event.order.pay.confirm'),
+        url(r'^order/(?P<order>[^/]+)/(?P<secret>[A-Za-z0-9]+)/pay/complete$',
+            pretix.presale.views.order.OrderPayComplete.as_view(),
+            name='event.order.pay.complete'),
         url(r'^order/(?P<order>[^/]+)/(?P<secret>[A-Za-z0-9]+)/download/(?P<output>[^/]+)$',
             pretix.presale.views.order.OrderDownload.as_view(),
             name='event.order.download'),
diff --git a/src/pretix/presale/views/async.py b/src/pretix/presale/views/async.py
new file mode 100644
index 0000000000..93b0e46c54
--- /dev/null
+++ b/src/pretix/presale/views/async.py
@@ -0,0 +1,122 @@
+import logging
+
+from django.conf import settings
+from django.contrib import messages
+from django.http import JsonResponse
+from django.shortcuts import redirect, render
+from django.utils.translation import ugettext as _
+
+logger = logging.getLogger('pretix.presale.async')
+
+
+class AsyncAction:
+    task = None
+    success_url = None
+    error_url = None
+
+    def do(self, *args):
+        if settings.HAS_CELERY:
+            from pretix.celery import app
+
+            if hasattr(self.task, 'task') and isinstance(self.task.task, app.Task):
+                return self._do_celery(args)
+            else:
+                raise TypeError('Method has no task attached')
+        else:
+            return self._do_sync(args)
+
+    def get_success_url(self, value):
+        return self.success_url
+
+    def get_error_url(self):
+        return self.error_url
+
+    def get_check_url(self, task_id, ajax):
+        return self.request.path + '?async_id=%s' % task_id + ('&ajax=1' if ajax else '')
+
+    def get(self, request, *args, **kwargs):
+        if 'async_id' in request.GET and settings.HAS_CELERY:
+            return self.get_result(request)
+        return self.http_method_not_allowed(request)
+
+    def get_result(self, request):
+        from celery.result import AsyncResult
+        res = AsyncResult(request.GET.get('async_id'))
+        if 'ajax' in self.request.GET:
+            data = {
+                'async_id': res.id,
+                'ready': res.ready()
+            }
+            if res.ready():
+                if res.successful():
+                    smes = self.get_success_message(res.info)
+                    if smes:
+                        messages.success(self.request, smes)
+                    # TODO: Do not store message if the ajax client stats that it will not redirect
+                    # but handle the mssage itself
+                    data.update({
+                        'redirect': self.get_success_url(res.info),
+                        'message': self.get_success_message(res.info)
+                    })
+                else:
+                    messages.error(self.request, self.get_error_message(res.info))
+                    # TODO: Do not store message if the ajax client stats that it will not redirect
+                    # but handle the mssage itself
+                    data.update({
+                        'redirect': self.get_error_url(),
+                        'message': self.get_error_message(res.info)
+                    })
+            return JsonResponse(data)
+        else:
+            if res.ready():
+                if res.successful():
+                    return self.success(res.info)
+                else:
+                    return self.error(res.info)
+            return render(request, 'pretixpresale/waiting.html')
+
+    def _do_celery(self, args):
+        rs = self.task.task.apply_async(args=args)
+        if 'ajax' in self.request.GET or 'ajax' in self.request.POST:
+            return JsonResponse({
+                'async_id': rs.id,
+                'check_url': self.get_check_url(rs.id, True)
+            })
+        else:
+            return redirect(self.get_check_url(rs.id, False))
+
+    def _do_sync(self, args):
+        try:
+            rs = getattr(self.__class__, 'task')(*args)
+            return self.success(rs)
+        except Exception as e:
+            logger.exception('Error while executing task synchronously')
+            return self.error(e)
+
+    def success(self, value):
+        smes = self.get_success_message(value)
+        if smes:
+            messages.success(self.request, smes)
+        if "ajax" in self.request.POST or "ajax" in self.request.GET:
+            return JsonResponse({
+                'ready': True,
+                'redirect': self.get_success_url(value),
+                'message': self.get_success_message(value)
+            })
+        return redirect(self.get_success_url(value))
+
+    def error(self, exception):
+        messages.error(self.request, self.get_error_message(exception))
+        if "ajax" in self.request.POST or "ajax" in self.request.GET:
+            return JsonResponse({
+                'ready': True,
+                'redirect': self.get_error_url(),
+                'message': self.get_error_message(exception)
+            })
+        return redirect(self.get_error_url())
+
+    def get_error_message(self, exception):
+        return _('An unexpected error has occured')
+
+    def get_success_message(self, value):
+        return _('The task has been completed')
diff --git a/src/pretix/presale/views/cart.py b/src/pretix/presale/views/cart.py
index 4e7aa189e4..c835056545 100644
--- a/src/pretix/presale/views/cart.py
+++ b/src/pretix/presale/views/cart.py
@@ -1,13 +1,15 @@
 from django.contrib import messages
 from django.core.urlresolvers import reverse
+from django.http import JsonResponse
 from django.shortcuts import redirect
-from django.utils.translation import ugettext_lazy as _
+from django.utils.translation import ugettext as _
 from django.views.generic import View
 
 from pretix.base.services.cart import (
     CartError, add_items_to_cart, remove_items_from_cart,
 )
 from pretix.presale.views import EventViewMixin
+from pretix.presale.views.async import AsyncAction
 
 
 class CartActionMixin:
@@ -15,18 +17,16 @@ class CartActionMixin:
     def get_next_url(self):
         if "next" in self.request.GET and '://' not in self.request.GET:
             return self.request.GET.get('next')
-        elif "HTTP_REFERER" in self.request.META:
-            return self.request.META.get('HTTP_REFERER')
         else:
             return reverse('presale:event.index', kwargs={
                 'event': self.request.event.slug,
                 'organizer': self.request.event.organizer.slug,
             })
 
-    def get_success_url(self):
+    def get_success_url(self, value=None):
         return self.get_next_url()
 
-    def get_failure_url(self):
+    def get_error_url(self):
         return self.get_next_url()
 
     def _items_from_post_data(self):
@@ -61,27 +61,34 @@ class CartRemove(EventViewMixin, CartActionMixin, View):
     def post(self, *args, **kwargs):
         items = self._items_from_post_data()
         if not items:
-            return redirect(self.get_failure_url())
+            return redirect(self.get_error_url())
 
         remove_items_from_cart(self.request.event.identity, items, self.request.session.session_key)
         messages.success(self.request, _('Your cart has been updated.'))
         return redirect(self.get_success_url())
 
 
-class CartAdd(EventViewMixin, CartActionMixin, View):
+class CartAdd(EventViewMixin, CartActionMixin, AsyncAction, View):
+    task = add_items_to_cart
 
-    def __init__(self, *args, **kwargs):
-        super().__init__(*args, **kwargs)
+    def get_success_message(self, value):
+        return _('The products have been successfully added to your cart.')
+
+    def get_error_message(self, exception):
+        if isinstance(exception, dict) and exception['exc_type'] == 'CartError':
+            return exception['exc_message']
+        elif isinstance(exception, CartError):
+            return str(exception)
+        return super().get_error_message(exception)
 
     def post(self, request, *args, **kwargs):
         items = self._items_from_post_data()
-        return self.process(items)
-
-    def process(self, items):
-        try:
-            add_items_to_cart(self.request.event.identity, items, self.request.session.session_key)
-            messages.success(self.request, _('The products have been successfully added to your cart.'))
-            return redirect(self.get_success_url())
-        except CartError as e:
-            messages.error(self.request, str(e))
-            return redirect(self.get_failure_url())
+        if items:
+            return self.do(self.request.event.identity, items, self.request.session.session_key)
+        else:
+            if 'ajax' in self.request.GET or 'ajax' in self.request.POST:
+                return JsonResponse({
+                    'redirect': self.get_error_url()
+                })
+            else:
+                return redirect(self.get_error_url())
diff --git a/src/pretix/presale/views/checkout.py b/src/pretix/presale/views/checkout.py
index d382b4871d..a6fd970a99 100644
--- a/src/pretix/presale/views/checkout.py
+++ b/src/pretix/presale/views/checkout.py
@@ -12,7 +12,7 @@ from pretix.presale.views import CartMixin
 class CheckoutView(CartMixin, View):
     def dispatch(self, request, *args, **kwargs):
         self.request = request
-        if not self.positions:
+        if not self.positions and "async_id" not in request.GET:
             messages.error(request, _("Your cart is empty"))
             return redirect(reverse('presale:event.index', kwargs={
                 'organizer': self.request.event.organizer.slug,
diff --git a/src/pretix/presale/views/order.py b/src/pretix/presale/views/order.py
index d436c94e9a..c0147ee397 100644
--- a/src/pretix/presale/views/order.py
+++ b/src/pretix/presale/views/order.py
@@ -107,7 +107,7 @@ class OrderPay(EventViewMixin, OrderDetailMixin, TemplateView):
                 or not self.payment_provider.order_can_retry(self.order)
                 or not self.payment_provider.is_enabled):
             messages.error(request, _('The payment for this order cannot be continued.'))
-            return redirect(self.get_order_url())
+            return redirect(self.get_order_url() + '?paid=yes')
         return super().dispatch(request, *args, **kwargs)
 
     def post(self, request, *args, **kwargs):
@@ -168,9 +168,30 @@ class OrderPayDo(EventViewMixin, OrderDetailMixin, TemplateView):
         ctx['payment_provider'] = self.payment_provider
         return ctx
 
-    @cached_property
-    def form(self):
-        return self.payment_provider.payment_form_render(self.request)
+    def get_payment_url(self):
+        return reverse('presale:event.order.pay', kwargs={
+            'event': self.request.event.slug,
+            'organizer': self.request.event.organizer.slug,
+            'order': self.order.code,
+            'secret': self.order.secret
+        })
+
+
+class OrderPayComplete(EventViewMixin, OrderDetailMixin, View):
+    def dispatch(self, request, *args, **kwargs):
+        self.request = request
+        if not self.order:
+            raise Http404(_('Unknown order code or not authorized to access this order.'))
+        if (not self.payment_provider.payment_is_valid_session(request)
+                or not self.payment_provider.is_enabled
+                or not self.payment_provider.is_allowed(request)):
+            messages.error(request, _('The payment information you entered was incomplete.'))
+            return redirect(self.get_payment_url())
+        return super().dispatch(request, *args, **kwargs)
+
+    def get(self, request, *args, **kwargs):
+        resp = self.payment_provider.payment_perform(request, self.order)
+        return redirect(resp or self.get_order_url() + '?paid=yes')
 
     def get_payment_url(self):
         return reverse('presale:event.order.pay', kwargs={
diff --git a/src/static/pretixpresale/js/ui/asynctask.js b/src/static/pretixpresale/js/ui/asynctask.js
new file mode 100644
index 0000000000..d6e2a79144
--- /dev/null
+++ b/src/static/pretixpresale/js/ui/asynctask.js
@@ -0,0 +1,65 @@
+var async_task_id = null;
+var async_task_timeout = null;
+var async_task_check_url = null;
+
+$(function () {
+    $("body").on('submit', 'form[data-asynctask]', function (e) {
+        e.preventDefault();
+        if ($(this).data('ajaxing')) return;
+        $(this).data('ajaxing', true);
+        waitingDialog.show(default_loading_message);
+
+        $.ajax(
+            {
+                'type': 'POST',
+                'url': $(this).attr('action'),
+                'data': $(this).serialize() + '&ajax=1',
+                'success': async_task_callback,
+                'error': async_task_error,
+                'context': this,
+                'dataType': 'json'
+            }
+        );
+    });
+});
+
+function async_task_check() {
+    $.ajax(
+        {
+            'type': 'GET',
+            'url': async_task_check_url,
+            'success': async_task_check_callback,
+            'error': async_task_error,
+            'context': this,
+            'dataType': 'json'
+        }
+    );
+}
+
+function async_task_check_callback(data, jqXHR, status) {
+    if (data.ready && data.redirect) {
+        location.href = data.redirect;
+        return;
+    }
+    async_task_timeout = window.setTimeout(async_task_check, 500);
+}
+
+function async_task_callback(data, jqXHR, status) {
+    $(this).data('ajaxing', false);
+    if (data.redirect) {
+        location.href = data.redirect;
+        return;
+    }
+    async_task_id = data.async_id;
+    async_task_check_url = data.check_url;
+    async_task_timeout = window.setTimeout(async_task_check, 500);
+}
+
+function async_task_error(jqXHR, textStatus, errorThrown) {
+    waitingDialog.hide();
+    // TODO
+    // if(jqXHR.status == 500) {
+    // } if(jqXHR.status == 403) {
+    // } if(jqXHR.status == 503) {
+    // }
+}
diff --git a/src/static/pretixpresale/js/ui/main.js b/src/static/pretixpresale/js/ui/main.js
index f237684ffc..1fd027ad87 100644
--- a/src/static/pretixpresale/js/ui/main.js
+++ b/src/static/pretixpresale/js/ui/main.js
@@ -13,62 +13,15 @@ $(function () {
     $(".collapsed").removeClass("collapsed").addClass("collapse");
 });
 
-
-/**
- * Module for displaying "Waiting for..." dialog using Bootstrap
- *
- * @author Eugene Maslovich <ehpc@em42.ru>
- * MIT License
- */
-
 var waitingDialog = (function ($) {
 
-    // Creating modal dialog's DOM
-    var $dialog = $(
-        '<div class="modal fade" data-backdrop="static" data-keyboard="false" tabindex="-1" role="dialog" aria-hidden="true" style="padding-top:15%; overflow-y:visible;">' +
-        '<div class="modal-dialog modal-m">' +
-        '<div class="modal-content">' +
-        '<div class="modal-header"><h3 style="margin:0;"></h3></div>' +
-        '<div class="modal-body">' +
-        '<div class="progress progress-striped active" style="margin-bottom:0;"><div class="progress-bar" style="width: 100%"></div></div>' +
-        '</div>' +
-        '</div></div></div>');
-
     return {
-        /**
-         * Opens our dialog
-         * @param message Custom message
-         * @param options Custom options:
-         *                  options.dialogSize - bootstrap postfix for dialog size, e.g. "sm", "m";
-         *                  options.progressType - bootstrap postfix for progress bar type, e.g. "success", "warning".
-         */
         show: function (message, options) {
-            // Assigning defaults
-            var settings = $.extend({
-                                        dialogSize: 'm',
-                                        progressType: ''
-                                    }, options);
-            if (typeof message === 'undefined') {
-                message = 'Loading';
-            }
-            if (typeof options === 'undefined') {
-                options = {};
-            }
-            // Configuring dialog
-            $dialog.find('.modal-dialog').attr('class', 'modal-dialog').addClass('modal-' + settings.dialogSize);
-            $dialog.find('.progress-bar').attr('class', 'progress-bar');
-            if (settings.progressType) {
-                $dialog.find('.progress-bar').addClass('progress-bar-' + settings.progressType);
-            }
-            $dialog.find('h3').text(message);
-            // Opening dialog
-            $dialog.modal();
+            $("#loadingmodal h1").html(message);
+            $("body").addClass("loading");
         },
-        /**
-         * Closes dialog
-         */
         hide: function () {
-            $dialog.modal('hide');
+            $("body").removeClass("loading");
         }
     }
 
diff --git a/src/static/pretixpresale/less/main.less b/src/static/pretixpresale/less/main.less
index 43b9c2808f..2ef78f5650 100644
--- a/src/static/pretixpresale/less/main.less
+++ b/src/static/pretixpresale/less/main.less
@@ -56,6 +56,44 @@ a:hover .panel-primary > .panel-heading {
         color: @brand-success;
     }
 }
+
+body.loading .container {
+    -webkit-filter: blur(2px);
+    -moz-filter: blur(2px);
+    -ms-filter: blur(2px);
+    -o-filter: blur(2px);
+    filter: blur(2px);
+}
+
+#loadingmodal {
+    position: fixed;
+    top: 0;
+    left: 0;
+    width: 100vw;
+    height: 100vh;
+    background: rgba(255, 255, 255, .7);
+    opacity: 0;
+    text-align: center;
+    z-index: 900000;
+    visibility: hidden;
+
+    .big-rotating-icon {
+        margin-top: 50px;
+        -webkit-animation: fa-spin 8s infinite linear;
+        animation: fa-spin 8s infinite linear;
+        font-size: 200px;
+        color: @brand-primary;
+    }
+}
+
+.loading #loadingmodal {
+    opacity: 1;
+    visibility: visible;
+    transition: opacity .5s ease-in-out;
+    -moz-transition: opacity .5s ease-in-out;
+    -webkit-transition: opacity .5s ease-in-out;
+}
+
 @media (min-width: @screen-md-min) {
     .thank-you {
         height: 170px;
diff --git a/src/static/pretixpresale/less/waiting.less b/src/static/pretixpresale/less/waiting.less
new file mode 100644
index 0000000000..0fee8b05dc
--- /dev/null
+++ b/src/static/pretixpresale/less/waiting.less
@@ -0,0 +1,19 @@
+@import "../../bootstrap/less/bootstrap.less";
+@import "../../fontawesome/less/font-awesome.less";
+@import "../../pretixbase/less/colors.less";
+
+@fa-font-path: "../../fontawesome/fonts";
+
+body {
+    background: #ececec;
+    text-align: center;
+    padding: 50px 0;
+}
+
+.big-rotating-icon {
+    margin-top: 50px;
+    -webkit-animation: fa-spin 8s infinite linear;
+    animation: fa-spin 8s infinite linear;
+    font-size: 200px;
+    color: @brand-primary;
+}
diff --git a/src/tests/base/test_orders.py b/src/tests/base/test_orders.py
index 78e0cd4704..35465d6cf0 100644
--- a/src/tests/base/test_orders.py
+++ b/src/tests/base/test_orders.py
@@ -5,7 +5,7 @@ from django.utils.timezone import now
 
 from pretix.base.models import Event, Organizer
 from pretix.base.payment import FreeOrderProvider
-from pretix.base.services.orders import place_order
+from pretix.base.services.orders import _create_order
 
 
 @pytest.fixture
@@ -22,9 +22,9 @@ def event():
 def test_expiry_days(event):
     today = now()
     event.settings.set('payment_term_days', 5)
-    order = place_order(event, email='dummy@example.org', positions=[],
-                        dt=today, payment_provider=FreeOrderProvider(event),
-                        locale='de')
+    order = _create_order(event, email='dummy@example.org', positions=[],
+                          dt=today, payment_provider=FreeOrderProvider(event),
+                          locale='de')
     assert (order.expires - today).days == 5
 
 
@@ -33,12 +33,12 @@ def test_expiry_last(event):
     today = now()
     event.settings.set('payment_term_days', 5)
     event.settings.set('payment_term_last', now() + timedelta(days=3))
-    order = place_order(event, email='dummy@example.org', positions=[],
-                        dt=today, payment_provider=FreeOrderProvider(event),
-                        locale='de')
+    order = _create_order(event, email='dummy@example.org', positions=[],
+                          dt=today, payment_provider=FreeOrderProvider(event),
+                          locale='de')
     assert (order.expires - today).days == 3
     event.settings.set('payment_term_last', now() + timedelta(days=7))
-    order = place_order(event, email='dummy@example.org', positions=[],
-                        dt=today, payment_provider=FreeOrderProvider(event),
-                        locale='de')
+    order = _create_order(event, email='dummy@example.org', positions=[],
+                          dt=today, payment_provider=FreeOrderProvider(event),
+                          locale='de')
     assert (order.expires - today).days == 5
diff --git a/src/tests/presale/test_cart.py b/src/tests/presale/test_cart.py
index ec37dd287f..d84ef1120e 100644
--- a/src/tests/presale/test_cart.py
+++ b/src/tests/presale/test_cart.py
@@ -217,23 +217,20 @@ class CartTest(CartTestMixin, TestCase):
         self.assertGreater(cp.expires, now())
 
     def test_renew_expired_successfully(self):
-        CartPosition.objects.create(
+        cp1 = CartPosition.objects.create(
             event=self.event, session=self.session_key, item=self.ticket,
             price=23, expires=now() - timedelta(minutes=10)
         )
         self.client.post('/%s/%s/cart/add' % (self.orga.slug, self.event.slug), {
+            'variation_%s_%s' % (self.shirt.identity, self.shirt_red.identity): '1'
         }, follow=True)
-        objs = list(CartPosition.objects.current.filter(session=self.session_key, event=self.event))
-        self.assertEqual(len(objs), 1)
-        self.assertEqual(objs[0].item, self.ticket)
-        self.assertIsNone(objs[0].variation)
-        self.assertEqual(objs[0].price, 23)
-        self.assertGreater(objs[0].expires, now())
+        obj = CartPosition.objects.current.get(identity=cp1.identity)
+        self.assertEqual(obj.item, self.ticket)
+        self.assertIsNone(obj.variation)
+        self.assertEqual(obj.price, 23)
+        self.assertGreater(obj.expires, now())
 
     def test_renew_questions(self):
-        """
-        Currently fails. See: https://github.com/pretix/pretix/issues/20
-        """
         cr1 = CartPosition.objects.create(
             event=self.event, session=self.session_key, item=self.ticket,
             price=23, expires=now() - timedelta(minutes=10)
@@ -247,23 +244,24 @@ class CartTest(CartTestMixin, TestCase):
             cartposition=cr1, question=q1, answer='23'
         ))
         self.client.post('/%s/%s/cart/add' % (self.orga.slug, self.event.slug), {
+            'item_' + self.ticket.identity: '1',
         }, follow=True)
-        objs = list(CartPosition.objects.current.filter(session=self.session_key, event=self.event))
-        self.assertEqual(len(objs), 1)
-        self.assertEqual(objs[0].answers.get(question=q1).answer, '23')
+        obj = CartPosition.objects.current.get(identity=cr1.identity)
+        self.assertEqual(obj.answers.get(question=q1).answer, '23')
 
     def test_renew_expired_failed(self):
         self.quota_tickets.size = 0
         self.quota_tickets.save()
-        CartPosition.objects.create(
+        cp1 = CartPosition.objects.create(
             event=self.event, session=self.session_key, item=self.ticket,
             price=23, expires=now() - timedelta(minutes=10)
         )
         response = self.client.post('/%s/%s/cart/add' % (self.orga.slug, self.event.slug), {
+            'item_' + self.ticket.identity: '1',
         }, follow=True)
         doc = BeautifulSoup(response.rendered_content)
         self.assertIn('no longer available', doc.select('.alert-danger')[0].text)
-        self.assertFalse(CartPosition.objects.current.filter(session=self.session_key, event=self.event).exists())
+        self.assertFalse(CartPosition.objects.current.filter(identity=cp1.identity).exists())
 
     def test_restriction_ok(self):
         self.event.plugins = 'tests.testdummy'
diff --git a/src/tests/presale/test_event.py b/src/tests/presale/test_event.py
index 34858d0962..3c38637b1f 100644
--- a/src/tests/presale/test_event.py
+++ b/src/tests/presale/test_event.py
@@ -12,7 +12,6 @@ from pretix.base.models import (
 
 
 class EventTestMixin:
-
     def setUp(self):
         super().setUp()
         self.orga = Organizer.objects.create(name='CCC', slug='ccc')
@@ -23,7 +22,6 @@ class EventTestMixin:
 
 
 class EventMiddlewareTest(EventTestMixin, BrowserTest):
-
     def setUp(self):
         super().setUp()
         self.driver.implicitly_wait(10)
@@ -38,7 +36,6 @@ class EventMiddlewareTest(EventTestMixin, BrowserTest):
 
 
 class ItemDisplayTest(EventTestMixin, BrowserTest):
-
     def setUp(self):
         super().setUp()
         self.driver.implicitly_wait(10)
@@ -141,6 +138,11 @@ class ItemDisplayTest(EventTestMixin, BrowserTest):
 
 
 class DeadlineTest(EventTestMixin, TestCase):
+    def setUp(self):
+        super().setUp()
+        q = Quota.objects.create(event=self.event, name='Quota', size=2)
+        self.item = Item.objects.create(event=self.event, name='Early-bird ticket', default_price=0, active=False)
+        q.items.add(self.item)
 
     def test_not_yet_started(self):
         self.event.presale_start = now() + datetime.timedelta(days=1)
@@ -153,6 +155,9 @@ class DeadlineTest(EventTestMixin, TestCase):
         self.assertNotIn('checkout-button-row', response.rendered_content)
         response = self.client.post(
             '/%s/%s/cart/add' % (self.orga.slug, self.event.slug),
+            {
+                'item_' + self.item.identity: '1',
+            },
             follow=True
         )
         self.assertIn('alert-danger', response.rendered_content)
@@ -169,6 +174,9 @@ class DeadlineTest(EventTestMixin, TestCase):
         self.assertNotIn('checkout-button-row', response.rendered_content)
         response = self.client.post(
             '/%s/%s/cart/add' % (self.orga.slug, self.event.slug),
+            {
+                'item_' + self.item.identity: '1'
+            },
             follow=True
         )
         self.assertIn('alert-danger', response.rendered_content)
@@ -185,7 +193,10 @@ class DeadlineTest(EventTestMixin, TestCase):
         self.assertNotIn('alert-info', response.rendered_content)
         self.assertIn('checkout-button-row', response.rendered_content)
         response = self.client.post(
-            '/%s/%s/cart/add' % (self.orga.slug, self.event.slug)
+            '/%s/%s/cart/add' % (self.orga.slug, self.event.slug),
+            {
+                'item_' + self.item.identity: '1'
+            }
         )
         self.assertNotEqual(response.status_code, 403)
 
@@ -200,6 +211,9 @@ class DeadlineTest(EventTestMixin, TestCase):
         self.assertNotIn('alert-info', response.rendered_content)
         self.assertIn('checkout-button-row', response.rendered_content)
         response = self.client.post(
-            '/%s/%s/cart/add' % (self.orga.slug, self.event.slug)
+            '/%s/%s/cart/add' % (self.orga.slug, self.event.slug),
+            {
+                'item_' + self.item.identity: '1'
+            }
         )
         self.assertNotEqual(response.status_code, 403)
diff --git a/src/tests/presale/test_orders.py b/src/tests/presale/test_orders.py
index b55bc91d96..43031574b3 100644
--- a/src/tests/presale/test_orders.py
+++ b/src/tests/presale/test_orders.py
@@ -7,7 +7,7 @@ from django.utils.timezone import now
 
 from pretix.base.models import (
     Event, Item, ItemCategory, ItemVariation, Order, OrderPosition, Organizer,
-    Property, PropertyValue, Question, Quota, User,
+    Property, PropertyValue, Question, Quota,
 )