diff --git a/uncloud/uncloud_pay/migrations/0015_stripecustomer.py b/uncloud/uncloud_pay/migrations/0015_stripecustomer.py
new file mode 100644
index 0000000..14fdbf0
--- /dev/null
+++ b/uncloud/uncloud_pay/migrations/0015_stripecustomer.py
@@ -0,0 +1,24 @@
+# Generated by Django 3.0.3 on 2020-03-03 13:56
+
+from django.conf import settings
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        migrations.swappable_dependency(settings.AUTH_USER_MODEL),
+        ('uncloud_pay', '0014_auto_20200303_1027'),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='StripeCustomer',
+            fields=[
+                ('id', models.AutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('stripe_id', models.CharField(max_length=32)),
+                ('owner', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, to=settings.AUTH_USER_MODEL)),
+            ],
+        ),
+    ]
diff --git a/uncloud/uncloud_pay/migrations/0016_auto_20200303_1552.py b/uncloud/uncloud_pay/migrations/0016_auto_20200303_1552.py
new file mode 100644
index 0000000..08e3f2f
--- /dev/null
+++ b/uncloud/uncloud_pay/migrations/0016_auto_20200303_1552.py
@@ -0,0 +1,25 @@
+# Generated by Django 3.0.3 on 2020-03-03 15:52
+
+from django.conf import settings
+from django.db import migrations, models
+import django.db.models.deletion
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        migrations.swappable_dependency(settings.AUTH_USER_MODEL),
+        ('uncloud_pay', '0015_stripecustomer'),
+    ]
+
+    operations = [
+        migrations.RemoveField(
+            model_name='stripecustomer',
+            name='id',
+        ),
+        migrations.AlterField(
+            model_name='stripecustomer',
+            name='owner',
+            field=models.OneToOneField(on_delete=django.db.models.deletion.CASCADE, primary_key=True, serialize=False, to=settings.AUTH_USER_MODEL),
+        ),
+    ]
diff --git a/uncloud/uncloud_pay/models.py b/uncloud/uncloud_pay/models.py
index 62fa098..fa775fc 100644
--- a/uncloud/uncloud_pay/models.py
+++ b/uncloud/uncloud_pay/models.py
@@ -7,6 +7,7 @@ from django.utils import timezone
 from math import ceil
 from datetime import timedelta
 from calendar import monthrange
+import uncloud_pay.stripe
 
 from decimal import Decimal
 import uuid
@@ -68,6 +69,20 @@ class PaymentMethod(models.Model):
     # Only used for "Stripe" source
     stripe_card_id = models.CharField(max_length=32, blank=True, null=True)
 
+    @property
+    def stripe_card_last4(self):
+        if self.source == 'stripe':
+            card_request = uncloud_pay.stripe.get_card(
+                    StripeCustomer.objects.get(owner=self.owner).stripe_id,
+                    self.stripe_card_id)
+            if card_request['error'] == None:
+                return card_request['response_object']['last4']
+            else:
+                return None
+        else:
+            return None
+
+
     def charge(self, amount):
         if amount > 0: # Make sure we don't charge negative amount by errors...
             if self.source == 'stripe':
@@ -85,6 +100,11 @@ class PaymentMethod(models.Model):
     class Meta:
         unique_together = [['owner', 'primary']]
 
+class StripeCustomer(models.Model):
+    owner = models.OneToOneField( get_user_model(),
+            primary_key=True,
+            on_delete=models.CASCADE)
+    stripe_id = models.CharField(max_length=32)
 
 ###
 # Bills & Payments.
diff --git a/uncloud/uncloud_pay/serializers.py b/uncloud/uncloud_pay/serializers.py
index 16b725a..f5136f6 100644
--- a/uncloud/uncloud_pay/serializers.py
+++ b/uncloud/uncloud_pay/serializers.py
@@ -34,9 +34,11 @@ class PaymentSerializer(serializers.ModelSerializer):
         fields = ['owner', 'amount', 'source', 'timestamp']
 
 class PaymentMethodSerializer(serializers.ModelSerializer):
+    stripe_card_last4 = serializers.IntegerField()
+
     class Meta:
         model = PaymentMethod
-        fields = ['source', 'description', 'primary']
+        fields = ['source', 'description', 'primary', 'stripe_card_last4']
 
 class CreditCardSerializer(serializers.Serializer):
     number = serializers.IntegerField()
@@ -51,41 +53,6 @@ class CreatePaymentMethodSerializer(serializers.ModelSerializer):
         model = PaymentMethod
         fields = ['source', 'description', 'primary', 'credit_card']
 
-    def create(self, validated_data):
-        credit_card = stripe.CreditCard(**validated_data.pop('credit_card'))
-        user = self.context['request'].user
-        customer = stripe.create_customer(user.username, user.email)
-        # TODO check customer error
-        customer_id = customer['response_object']['id']
-        stripe_card = stripe.create_card(customer_id, credit_card)
-        # TODO: check credit card error
-        validated_data['stripe_card_id'] = stripe_card['response_object']['id']
-class CreditCardSerializer(serializers.Serializer):
-    number = serializers.IntegerField()
-    exp_month = serializers.IntegerField()
-    exp_year = serializers.IntegerField()
-    cvc = serializers.IntegerField()
-
-class CreatePaymentMethodSerializer(serializers.ModelSerializer):
-    credit_card = CreditCardSerializer()
-
-    class Meta:
-        model = PaymentMethod
-        fields = ['source', 'description', 'primary', 'credit_card']
-
-    def create(self, validated_data):
-        credit_card = stripe.CreditCard(**validated_data.pop('credit_card'))
-        user = self.context['request'].user
-        customer = stripe.create_customer(user.username, user.email)
-        # TODO check customer error
-        customer_id = customer['response_object']['id']
-        stripe_card = stripe.create_card(customer_id, credit_card)
-        # TODO: check credit card error
-        validated_data['stripe_card_id'] = stripe_card['response_object']['id']
-        payment_method = PaymentMethod.objects.create(**validated_data)
-        return payment_method
-        payment_method = PaymentMethod.objects.create(**validated_data)
-        return payment_method
 
 ###
 # Bills
diff --git a/uncloud/uncloud_pay/stripe.py b/uncloud/uncloud_pay/stripe.py
index c50317f..ab2d865 100644
--- a/uncloud/uncloud_pay/stripe.py
+++ b/uncloud/uncloud_pay/stripe.py
@@ -2,6 +2,9 @@ import stripe
 import stripe.error
 import logging
 
+from django.core.exceptions import ObjectDoesNotExist
+import uncloud_pay.models
+
 import uncloud.secrets
 
 # Static stripe configuration used below.
@@ -79,11 +82,24 @@ class CreditCard():
 
 # Actual Stripe logic.
 
+def get_customer_id_for(user):
+    try:
+        # .get() raise if there is no matching entry.
+        return uncloud_pay.models.StripeCustomer.objects.get(owner=user).stripe_id
+    except ObjectDoesNotExist:
+        # No entry yet - making a new one.
+        customer_request = create_customer(user.username, user.email)
+        if customer_request['error'] == None:
+            mapping = uncloud_pay.models.StripeCustomer.objects.create(
+                    owner=user,
+                    stripe_id=customer_request['response_object']['id']
+                    )
+            return mapping.stripe_id
+        else:
+            return None
+
 @handle_stripe_error
 def create_card(customer_id, credit_card):
-    # Test settings
-    credit_card.number = "5555555555554444"
-
     return stripe.Customer.create_source(
             customer_id,
             card={
@@ -95,7 +111,7 @@ def create_card(customer_id, credit_card):
 
 @handle_stripe_error
 def get_card(customer_id, card_id):
-    return stripe.Card.retrieve_source(customer_id, card_id)
+    return stripe.Customer.retrieve_source(customer_id, card_id)
 
 @handle_stripe_error
 def charge_customer(amount, source):
diff --git a/uncloud/uncloud_pay/views.py b/uncloud/uncloud_pay/views.py
index 936d4c7..294b518 100644
--- a/uncloud/uncloud_pay/views.py
+++ b/uncloud/uncloud_pay/views.py
@@ -1,4 +1,5 @@
 from django.shortcuts import render
+from django.db import transaction
 from django.contrib.auth import get_user_model
 from rest_framework import viewsets, permissions, status
 from rest_framework.response import Response
@@ -69,13 +70,34 @@ class PaymentMethodViewSet(viewsets.ModelViewSet):
     def get_queryset(self):
         return PaymentMethod.objects.filter(owner=self.request.user)
 
+    # XXX: Handling of errors is far from great down there.
+    @transaction.atomic
     def create(self, request):
         serializer = self.get_serializer(data=request.data)
         serializer.is_valid(raise_exception=True)
-        serializer.save(owner=request.user)
 
-        headers = self.get_success_headers(serializer.data)
-        return Response(serializer.data, status=status.HTTP_201_CREATED, headers=headers)
+        # Retrieve Stripe customer ID for user.
+        customer_id  = stripe.get_customer_id_for(request.user)
+        if customer_id == None:
+            return Response(
+                    {'error': 'Could not resolve customer stripe ID.'},
+                    status=status.HTTP_500_INTERNAL_SERVER_ERROR)
+
+        # Register card under stripe customer.
+        credit_card = stripe.CreditCard(**serializer.validated_data.pop('credit_card'))
+        card_request = stripe.create_card(customer_id, credit_card)
+        if card_request['error']:
+            return Response({'stripe_error': card_request['error']}, status=status.HTTP_500_INTERNAL_SERVER_ERROR)
+        card_id = card_request['response_object']['id']
+
+        # Save payment method locally.
+        serializer.validated_data['stripe_card_id'] = card_request['response_object']['id']
+        payment_method = PaymentMethod.objects.create(owner=request.user, **serializer.validated_data)
+
+        # We do not want to return the credit card details sent with the POST
+        # request.
+        output_serializer = PaymentMethodSerializer(payment_method)
+        return Response(output_serializer.data)
 
     # TODO: find a way to customize serializer for actions.
     # drf-action-serializer module seems to do that.