diff --git a/doc/api/resources/orders.rst b/doc/api/resources/orders.rst
index a8014a451..1beb5ed81 100644
--- a/doc/api/resources/orders.rst
+++ b/doc/api/resources/orders.rst
@@ -231,6 +231,15 @@ created                               datetime                   Date and time o
 payment_date                          datetime                   Date and time of completion of this payment (or ``null``)
 provider                              string                     Identification string of the payment provider
 payment_url                           string                     The URL where an user can continue with the payment (or ``null``)
+details                               object                     Payment-specific information. This is a dictionary
+                                                                 with various fields that can be different between
+                                                                 payment providers, versions, payment states, etc. If
+                                                                 you read this field, you always need to be able to
+                                                                 deal with situations where values that you expect are
+                                                                 missing. Mostly, the field contains various IDs that
+                                                                 can be used for matching with other systems. If a
+                                                                 payment provider does not implement this feature,
+                                                                 the object is empty.
 ===================================== ========================== =======================================================
 
 .. versionchanged:: 2.0
@@ -239,7 +248,7 @@ payment_url                           string                     The URL where a
 
 .. versionchanged:: 3.1
 
-  The attribute ``payment_url`` has been added.
+  The attributes ``payment_url`` and ``details`` have been added.
 
 .. _order-refund-resource:
 
diff --git a/doc/development/api/payment.rst b/doc/development/api/payment.rst
index 4279268f0..cc83ce418 100644
--- a/doc/development/api/payment.rst
+++ b/doc/development/api/payment.rst
@@ -108,6 +108,8 @@ The provider class
 
    .. automethod:: execute_refund
 
+   .. automethod:: api_payment_details
+
    .. automethod:: shred_payment_info
 
    .. autoattribute:: is_implicit
diff --git a/src/pretix/api/serializers/order.py b/src/pretix/api/serializers/order.py
index 04b6f5fb5..e664356b5 100644
--- a/src/pretix/api/serializers/order.py
+++ b/src/pretix/api/serializers/order.py
@@ -297,12 +297,22 @@ class PaymentURLField(serializers.URLField):
         })
 
 
+class PaymentDetailsField(serializers.Field):
+    def to_representation(self, value: OrderPayment):
+        pp = value.payment_provider
+        if not pp:
+            return {}
+        return pp.api_payment_details(value)
+
+
 class OrderPaymentSerializer(I18nAwareModelSerializer):
     payment_url = PaymentURLField(source='*', allow_null=True, read_only=True)
+    details = PaymentDetailsField(source='*', allow_null=True, read_only=True)
 
     class Meta:
         model = OrderPayment
-        fields = ('local_id', 'state', 'amount', 'created', 'payment_date', 'provider', 'payment_url')
+        fields = ('local_id', 'state', 'amount', 'created', 'payment_date', 'provider', 'payment_url',
+                  'details')
 
 
 class OrderRefundSerializer(I18nAwareModelSerializer):
diff --git a/src/pretix/base/models/event.py b/src/pretix/base/models/event.py
index b4d103e1f..bfbc52837 100644
--- a/src/pretix/base/models/event.py
+++ b/src/pretix/base/models/event.py
@@ -608,22 +608,24 @@ class Event(EventMixin, LoggedModel):
             question_map=question_map
         )
 
-    def get_payment_providers(self) -> dict:
+    def get_payment_providers(self, cached=False) -> dict:
         """
         Returns a dictionary of initialized payment providers mapped by their identifiers.
         """
         from ..signals import register_payment_providers
 
-        responses = register_payment_providers.send(self)
-        providers = {}
-        for receiver, response in responses:
-            if not isinstance(response, list):
-                response = [response]
-            for p in response:
-                pp = p(self)
-                providers[pp.identifier] = pp
+        if not cached or not hasattr(self, '_cached_payment_providers'):
+            responses = register_payment_providers.send(self)
+            providers = {}
+            for receiver, response in responses:
+                if not isinstance(response, list):
+                    response = [response]
+                for p in response:
+                    pp = p(self)
+                    providers[pp.identifier] = pp
 
-        return OrderedDict(sorted(providers.items(), key=lambda v: str(v[1].verbose_name)))
+            self._cached_payment_providers = OrderedDict(sorted(providers.items(), key=lambda v: str(v[1].verbose_name)))
+        return self._cached_payment_providers
 
     def get_html_mail_renderer(self):
         """
diff --git a/src/pretix/base/models/orders.py b/src/pretix/base/models/orders.py
index 91e0561ef..9dc46747b 100644
--- a/src/pretix/base/models/orders.py
+++ b/src/pretix/base/models/orders.py
@@ -1196,7 +1196,7 @@ class OrderPayment(models.Model):
         """
         Cached access to an instance of the payment provider in use.
         """
-        return self.order.event.get_payment_providers().get(self.provider)
+        return self.order.event.get_payment_providers(cached=True).get(self.provider)
 
     def _mark_paid(self, force, count_waitinglist, user, auth, ignore_date=False, overpaid=False):
         from pretix.base.signals import order_paid
diff --git a/src/pretix/base/payment.py b/src/pretix/base/payment.py
index 7c4094870..1a61d8844 100644
--- a/src/pretix/base/payment.py
+++ b/src/pretix/base/payment.py
@@ -657,6 +657,15 @@ class BasePaymentProvider:
         obj.info = '{}'
         obj.save(update_fields=['info'])
 
+    def api_payment_details(self, payment: OrderPayment):
+        """
+        Will be called to populate the ``details`` parameter of the payment in the REST API.
+
+        :param payment: The payment in question.
+        :return: A serializable dictionary
+        """
+        return {}
+
 
 class PaymentException(Exception):
     pass
@@ -720,6 +729,12 @@ class BoxOfficeProvider(BasePaymentProvider):
     def order_change_allowed(self, order: Order) -> bool:
         return False
 
+    def api_payment_details(self, payment: OrderPayment):
+        return {
+            "pos_id": payment.info_data.get('pos_id', None),
+            "receipt_id": payment.info_data.get('receipt_id', None),
+        }
+
     def payment_control_render(self, request, payment) -> str:
         if not payment.info:
             return
@@ -864,6 +879,11 @@ class OffsettingProvider(BasePaymentProvider):
     def order_change_allowed(self, order: Order) -> bool:
         return False
 
+    def api_payment_details(self, payment: OrderPayment):
+        return {
+            "orders": payment.info_data.get('orders', []),
+        }
+
     def payment_control_render(self, request: HttpRequest, payment: OrderPayment) -> str:
         return _('Balanced against orders: %s' % ', '.join(payment.info_data['orders']))
 
diff --git a/src/pretix/plugins/paypal/payment.py b/src/pretix/plugins/paypal/payment.py
index 2d18e4cbd..dd0f6f5df 100644
--- a/src/pretix/plugins/paypal/payment.py
+++ b/src/pretix/plugins/paypal/payment.py
@@ -395,6 +395,20 @@ class Paypal(BasePaymentProvider):
                'retry': retry, 'order': payment.order}
         return template.render(ctx)
 
+    def api_payment_details(self, payment: OrderPayment):
+        sale_id = None
+        for trans in payment.info_data.get('transactions', []):
+            for res in trans.get('related_resources', []):
+                if 'sale' in res and 'id' in res['sale']:
+                    sale_id = res['sale']['id']
+        return {
+            "payer_email": payment.info_data.get('payer', {}).get('payer_info', {}).get('email'),
+            "payer_id": payment.info_data.get('payer', {}).get('payer_info', {}).get('payer_id'),
+            "cart_id": payment.info_data.get('cart', None),
+            "payment_id": payment.info_data.get('id', None),
+            "sale_id": sale_id,
+        }
+
     def payment_control_render(self, request: HttpRequest, payment: OrderPayment):
         template = get_template('pretixplugins/paypal/control.html')
         ctx = {'request': request, 'event': self.event, 'settings': self.settings,
diff --git a/src/pretix/plugins/stripe/payment.py b/src/pretix/plugins/stripe/payment.py
index 26d2aef21..1342e17f6 100644
--- a/src/pretix/plugins/stripe/payment.py
+++ b/src/pretix/plugins/stripe/payment.py
@@ -411,6 +411,12 @@ class StripeMethod(BasePaymentProvider):
         }
         return template.render(ctx)
 
+    def api_payment_details(self, payment: OrderPayment):
+        return {
+            "id": payment.info_data.get("id", None),
+            "payment_method": payment.info_data.get("payment_method", None)
+        }
+
     def payment_control_render(self, request, payment) -> str:
         if payment.info:
             payment_info = json.loads(payment.info)
diff --git a/src/tests/api/test_orders.py b/src/tests/api/test_orders.py
index 3e3151a6d..a91d4eca6 100644
--- a/src/tests/api/test_orders.py
+++ b/src/tests/api/test_orders.py
@@ -160,6 +160,10 @@ TEST_PAYMENTS_RES = [
         "payment_date": "2017-12-01T10:00:00Z",
         "provider": "stripe",
         "payment_url": None,
+        "details": {
+            "id": None,
+            "payment_method": None
+        },
         "state": "refunded",
         "amount": "23.00"
     },
@@ -169,6 +173,7 @@ TEST_PAYMENTS_RES = [
         "payment_date": None,
         "provider": "banktransfer",
         "payment_url": None,
+        "details": {},
         "state": "pending",
         "amount": "23.00"
     }