diff --git a/lib/messages.dart b/lib/messages.dart
index f4a69fb..b6f3552 100644
--- a/lib/messages.dart
+++ b/lib/messages.dart
@@ -1,7 +1,6 @@
 import 'package:json_annotation/json_annotation.dart';
 import 'package:stripe/src/messages/converters.dart';
 import 'package:stripe/src/messages/enums.dart';
-import 'package:stripe/src/messages/enums/pause_collection_behavior.dart';
 
 export 'package:stripe/src/messages/enums.dart';
 
@@ -19,8 +18,8 @@ part 'src/messages/data_list.dart';
 part 'src/messages/discount.dart';
 part 'src/messages/event.dart';
 part 'src/messages/invoice.dart';
-part 'src/messages/payment_intent.dart';
 part 'src/messages/pause_collection.dart';
+part 'src/messages/payment_intent.dart';
 part 'src/messages/payment_method.dart';
 part 'src/messages/portal_session.dart';
 part 'src/messages/price.dart';
diff --git a/lib/src/expanded/customer_expanded.dart b/lib/src/expanded/customer_expanded.dart
new file mode 100644
index 0000000..272e2a9
--- /dev/null
+++ b/lib/src/expanded/customer_expanded.dart
@@ -0,0 +1,9 @@
+import 'package:stripe/messages.dart';
+
+class CustomerExpanded {
+  final Customer customer;
+
+  CustomerExpanded({
+    required this.customer,
+  });
+}
diff --git a/lib/src/expanded/discount_expanded.dart b/lib/src/expanded/discount_expanded.dart
new file mode 100644
index 0000000..0bcd83e
--- /dev/null
+++ b/lib/src/expanded/discount_expanded.dart
@@ -0,0 +1,9 @@
+import 'package:stripe/messages.dart';
+
+class DiscountExpanded {
+  final Discount discount;
+
+  DiscountExpanded({
+    required this.discount,
+  });
+}
diff --git a/lib/src/expanded/invoice_expanded.dart b/lib/src/expanded/invoice_expanded.dart
index 98f0d15..9da7f76 100644
--- a/lib/src/expanded/invoice_expanded.dart
+++ b/lib/src/expanded/invoice_expanded.dart
@@ -1,36 +1,14 @@
 import 'package:stripe/messages.dart';
-import 'package:stripe/src/utils/expandable_fields/discounts_expandable_field.dart';
-import 'package:stripe/src/utils/expandable_fields/payment_intent_expandable_field.dart';
+import 'package:stripe/src/expanded/discount_expanded.dart';
 
 class InvoiceExpanded {
   final Invoice invoice;
   final PaymentIntent? paymentIntent;
-  final List<Discount>? discounts;
+  final List<DiscountExpanded>? discounts;
 
   InvoiceExpanded({
     required this.invoice,
     this.paymentIntent,
     this.discounts,
   });
-
-  factory InvoiceExpanded.fromJson(
-    Map<String, dynamic> json,
-    Set<InvoiceExpandableField> expand,
-  ) {
-    PaymentIntent? paymentIntent;
-    if (expand.contains(InvoiceExpandableField.paymentIntent)) {
-      paymentIntent = PaymentIntentExpandableField().extract(json);
-    }
-
-    List<Discount>? discounts;
-    if (expand.contains(InvoiceExpandableField.discounts)) {
-      discounts = DiscountsExpandableField().extract(json);
-    }
-
-    return InvoiceExpanded(
-      invoice: Invoice.fromJson(json),
-      paymentIntent: paymentIntent,
-      discounts: discounts,
-    );
-  }
 }
diff --git a/lib/src/expanded/subscription_expanded.dart b/lib/src/expanded/subscription_expanded.dart
index 87d7dfa..30f7b86 100644
--- a/lib/src/expanded/subscription_expanded.dart
+++ b/lib/src/expanded/subscription_expanded.dart
@@ -1,14 +1,13 @@
 import 'package:stripe/messages.dart';
 import 'package:stripe/src/expanded.dart';
-import 'package:stripe/src/utils/expandable_fields/customer_expandable_field.dart';
-import 'package:stripe/src/utils/expandable_fields/discounts_expandable_field.dart';
-import 'package:stripe/src/utils/expandable_fields/latest_invoice_expanded_expandable_field.dart';
+import 'package:stripe/src/expanded/customer_expanded.dart';
+import 'package:stripe/src/expanded/discount_expanded.dart';
 
 class SubscriptionExpanded {
   final Subscription subscription;
-  final List<Discount>? discounts;
+  final List<DiscountExpanded>? discounts;
   final InvoiceExpanded? latestInvoice;
-  final Customer? customer;
+  final CustomerExpanded? customer;
 
   SubscriptionExpanded({
     required this.subscription,
@@ -16,33 +15,4 @@ class SubscriptionExpanded {
     this.latestInvoice,
     this.customer,
   });
-
-  factory SubscriptionExpanded.fromJson(
-    Map<String, dynamic> json,
-    Set<SubscriptionExpandableField> expand,
-  ) {
-    List<Discount>? discounts;
-    if (expand.contains(SubscriptionExpandableField.discounts)) {
-      discounts = const DiscountsExpandableField().extract(json);
-    }
-
-    InvoiceExpanded? latestInvoice;
-    if (expand.contains(SubscriptionExpandableField.latestInvoice)) {
-      latestInvoice = const LatestInvoiceExpandedExpandableField(
-        expand: {InvoiceExpandableField.paymentIntent},
-      ).extract(json);
-    }
-
-    Customer? customer;
-    if (expand.contains(SubscriptionExpandableField.customer)) {
-      customer = const CustomerExpandableField().extract(json);
-    }
-
-    return SubscriptionExpanded(
-      subscription: Subscription.fromJson(json),
-      discounts: discounts,
-      latestInvoice: latestInvoice,
-      customer: customer,
-    );
-  }
 }
diff --git a/lib/src/messages/enums.dart b/lib/src/messages/enums.dart
index 680b4dc..75b538d 100644
--- a/lib/src/messages/enums.dart
+++ b/lib/src/messages/enums.dart
@@ -1,5 +1,3 @@
-export 'enums/expandable_fields/invoice_expandable_field.dart';
-export 'enums/expandable_fields/subscription_expandable_field.dart';
 export 'enums/payment_behavior.dart';
 export 'enums/proration_behavior.dart';
 export 'enums/stripe_api_error_type.dart';
diff --git a/lib/src/messages/enums/expandable_fields/invoice_expandable_field.dart b/lib/src/messages/enums/expandable_fields/invoice_expandable_field.dart
deleted file mode 100644
index d970151..0000000
--- a/lib/src/messages/enums/expandable_fields/invoice_expandable_field.dart
+++ /dev/null
@@ -1,8 +0,0 @@
-import 'package:json_annotation/json_annotation.dart';
-
-enum InvoiceExpandableField {
-  @JsonValue('payment_intent')
-  paymentIntent,
-  @JsonValue('discounts')
-  discounts,
-}
diff --git a/lib/src/messages/enums/expandable_fields/subscription_expandable_field.dart b/lib/src/messages/enums/expandable_fields/subscription_expandable_field.dart
deleted file mode 100644
index c148873..0000000
--- a/lib/src/messages/enums/expandable_fields/subscription_expandable_field.dart
+++ /dev/null
@@ -1,5 +0,0 @@
-enum SubscriptionExpandableField {
-  discounts,
-  latestInvoice,
-  customer,
-}
diff --git a/lib/src/resources/invoice.dart b/lib/src/resources/invoice.dart
index aa5206d..2172328 100644
--- a/lib/src/resources/invoice.dart
+++ b/lib/src/resources/invoice.dart
@@ -2,9 +2,7 @@ import 'dart:async';
 
 import 'package:stripe/messages.dart';
 import 'package:stripe/src/expanded.dart';
-import 'package:stripe/src/utils/expandable_field.dart';
-import 'package:stripe/src/utils/expandable_fields/discounts_expandable_field.dart';
-import 'package:stripe/src/utils/expandable_fields/payment_intent_expandable_field.dart';
+import 'package:stripe/src/utils/expandable_fields/invoice_expandable_field.dart';
 
 import '../client.dart';
 import '_resource.dart';
@@ -23,36 +21,16 @@ class InvoiceResource extends Resource<Invoice> {
 
   Future<InvoiceExpanded> createPreviewExpanded(
     CreatePreviewInvoiceRequest request, {
-    required Set<InvoiceExpandableField> expand,
+    required InvoiceExpandableField expand,
   }) async {
-    final expandableFields = _expandableFields(expand);
     final response = await post(
       '$_resourceName/create_preview',
       data: {
         ...request.toJson(),
-        'expand': expandableFields.map((e) => e.field).toList(),
+        'expand': expand.innerNestedFields.toList(),
       },
     );
 
-    return InvoiceExpanded.fromJson(response, expand);
-  }
-
-  Iterable<ExpandableField> _expandableFields(
-    Set<InvoiceExpandableField> fields,
-  ) {
-    return fields.map(
-      (field) => _expandableField(field),
-    );
-  }
-
-  ExpandableField _expandableField(
-    InvoiceExpandableField field,
-  ) {
-    switch (field) {
-      case InvoiceExpandableField.paymentIntent:
-        return PaymentIntentExpandableField();
-      case InvoiceExpandableField.discounts:
-        return DiscountsExpandableField();
-    }
+    return expand.parse(response);
   }
 }
diff --git a/lib/src/resources/subscription.dart b/lib/src/resources/subscription.dart
index 6b6c3e7..9185cfd 100644
--- a/lib/src/resources/subscription.dart
+++ b/lib/src/resources/subscription.dart
@@ -2,10 +2,9 @@ import 'dart:async';
 
 import 'package:stripe/messages.dart';
 import 'package:stripe/src/expanded.dart';
-import 'package:stripe/src/utils/expandable_field.dart';
-import 'package:stripe/src/utils/expandable_fields/customer_expandable_field.dart';
 import 'package:stripe/src/utils/expandable_fields/discounts_expandable_field.dart';
-import 'package:stripe/src/utils/expandable_fields/latest_invoice_expanded_expandable_field.dart';
+import 'package:stripe/src/utils/expandable_fields/latest_invoice_expandable_field.dart';
+import 'package:stripe/src/utils/expandable_fields/subscription_expandable_field.dart';
 
 import '../client.dart';
 import '_resource.dart';
@@ -19,10 +18,10 @@ class SubscriptionResource extends Resource<Subscription> {
   Future<SubscriptionExpanded> create(CreateSubscriptionRequest request) async {
     final response = await post(_resourceName, data: request.toJson());
 
-    return SubscriptionExpanded.fromJson(response, {
-      SubscriptionExpandableField.discounts,
-      SubscriptionExpandableField.latestInvoice,
-    });
+    return SubscriptionExpandableField(
+      discountsExpansion: DiscountsExpandableField(),
+      latestInvoiceExpansion: LatestInvoiceExpandableField(),
+    ).extract(response)!;
   }
 
   Future<Subscription> retrieve(String id) async {
@@ -32,40 +31,17 @@ class SubscriptionResource extends Resource<Subscription> {
 
   Future<SubscriptionExpanded> retrieveExpanded(
     String id, {
-    required Set<SubscriptionExpandableField> expand,
+    required SubscriptionExpandableField expand,
   }) async {
-    final expandableFields = _expandableFields(expand);
     final response = await get(
       '$_resourceName/$id',
       queryParameters: {
-        'expand': expandableFields.map((e) => e.field).toList(),
+        for (int i = 0; i < expand.innerNestedFields.length; i++)
+          'expand[$i]': expand.innerNestedFields.elementAt(i),
       },
     );
 
-    return SubscriptionExpanded.fromJson(response, expand);
-  }
-
-  Iterable<ExpandableField> _expandableFields(
-    Set<SubscriptionExpandableField> fields,
-  ) {
-    return fields.map(
-      (field) => _expandableField(field),
-    );
-  }
-
-  ExpandableField _expandableField(
-    SubscriptionExpandableField field,
-  ) {
-    switch (field) {
-      case SubscriptionExpandableField.discounts:
-        return DiscountsExpandableField();
-      case SubscriptionExpandableField.latestInvoice:
-        return LatestInvoiceExpandedExpandableField(
-          expand: {InvoiceExpandableField.paymentIntent},
-        );
-      case SubscriptionExpandableField.customer:
-        return CustomerExpandableField();
-    }
+    return expand.parse(response);
   }
 
   Future<DataList<Subscription>> list(
@@ -76,25 +52,20 @@ class SubscriptionResource extends Resource<Subscription> {
   }
 
   Future<DataList<SubscriptionExpanded>> listExpanded({
-    required Set<SubscriptionExpandableField> expand,
+    required SubscriptionExpandableField expand,
     ListSubscriptionsRequest? request,
   }) async {
-    final expandableFields = _expandableFields(expand);
-
     final response = await get(
       _resourceName,
       queryParameters: {
         ...?request?.toJson(),
-        'expand': expandableFields.map((e) => 'data.${e.field}').toList(),
+        'expand': expand.nestedFields.toList(),
       },
     );
 
     return DataList<SubscriptionExpanded>.fromJson(
       response,
-      (value) => SubscriptionExpanded.fromJson(
-        value as Map<String, dynamic>,
-        expand,
-      ),
+      (value) => expand.extract(value as Map<String, Object?>)!,
     );
   }
 
diff --git a/lib/src/utils/expandable_field.dart b/lib/src/utils/expandable_field.dart
index 680d144..bf4ddda 100644
--- a/lib/src/utils/expandable_field.dart
+++ b/lib/src/utils/expandable_field.dart
@@ -1,6 +1,14 @@
 abstract class ExpandableField<T> {
   String get field;
 
+  Iterable<String> get innerNestedFields => [];
+
+  Iterable<String> get nestedFields {
+    if (innerNestedFields.isEmpty) return [field];
+
+    return innerNestedFields.map((nestedField) => '$field.$nestedField');
+  }
+
   const ExpandableField();
 
   T extract(Map<String, dynamic> json);
diff --git a/lib/src/utils/expandable_fields/customer_expandable_field.dart b/lib/src/utils/expandable_fields/customer_expandable_field.dart
index d6d70af..f4f164f 100644
--- a/lib/src/utils/expandable_fields/customer_expandable_field.dart
+++ b/lib/src/utils/expandable_fields/customer_expandable_field.dart
@@ -1,15 +1,17 @@
 import 'package:stripe/messages.dart';
+import 'package:stripe/src/expanded/customer_expanded.dart';
 import 'package:stripe/src/utils/expandable_object_field.dart';
 
-class CustomerExpandableField extends ExpandableObjectField<Customer> {
+class CustomerExpandableField extends ExpandableObjectField<CustomerExpanded> {
   @override
   String get field => 'customer';
 
   const CustomerExpandableField();
 
   @override
-  Customer parse(Map<String, dynamic> object) => Customer.fromJson(object);
+  CustomerExpanded parse(Map<String, dynamic> object) =>
+      CustomerExpanded(customer: Customer.fromJson(object));
 
   @override
-  String replacement(Customer parsedValue) => parsedValue.id;
+  String replacement(CustomerExpanded parsedValue) => parsedValue.customer.id;
 }
diff --git a/lib/src/utils/expandable_fields/discounts_expandable_field.dart b/lib/src/utils/expandable_fields/discounts_expandable_field.dart
index 2f8addb..0c9ddfc 100644
--- a/lib/src/utils/expandable_fields/discounts_expandable_field.dart
+++ b/lib/src/utils/expandable_fields/discounts_expandable_field.dart
@@ -1,16 +1,19 @@
 import 'package:stripe/messages.dart';
+import 'package:stripe/src/expanded/discount_expanded.dart';
 import 'package:stripe/src/utils/expandable_list_field.dart';
 
-class DiscountsExpandableField extends ExpandableListField<Discount> {
+class DiscountsExpandableField extends ExpandableListField<DiscountExpanded> {
   @override
   String get field => 'discounts';
 
   const DiscountsExpandableField();
 
   @override
-  String elementReplacement(Discount element) => element.id;
+  String elementReplacement(DiscountExpanded element) => element.discount.id;
 
   @override
-  Discount parseElement(Map<String, dynamic> element) =>
-      Discount.fromJson(element);
+  DiscountExpanded parseElement(Map<String, dynamic> element) =>
+      DiscountExpanded(
+        discount: Discount.fromJson(element),
+      );
 }
diff --git a/lib/src/utils/expandable_fields/invoice_expandable_field.dart b/lib/src/utils/expandable_fields/invoice_expandable_field.dart
new file mode 100644
index 0000000..7fa35a9
--- /dev/null
+++ b/lib/src/utils/expandable_fields/invoice_expandable_field.dart
@@ -0,0 +1,49 @@
+import 'package:stripe/messages.dart';
+import 'package:stripe/src/expanded.dart';
+import 'package:stripe/src/expanded/discount_expanded.dart';
+import 'package:stripe/src/utils/expandable_fields/discounts_expandable_field.dart';
+import 'package:stripe/src/utils/expandable_fields/payment_intent_expandable_field.dart';
+import 'package:stripe/src/utils/expandable_object_field.dart';
+
+class InvoiceExpandableField extends ExpandableObjectField<InvoiceExpanded> {
+  final PaymentIntentExpandableField? paymentIntentExpansion;
+  final DiscountsExpandableField? discountsExpansion;
+
+  @override
+  String get field => 'invoice';
+
+  @override
+  Iterable<String> get innerNestedFields => [
+        ...?paymentIntentExpansion?.nestedFields,
+        ...?discountsExpansion?.nestedFields,
+      ];
+
+  const InvoiceExpandableField({
+    this.paymentIntentExpansion,
+    this.discountsExpansion,
+  });
+
+  @override
+  InvoiceExpanded parse(Map<String, dynamic> object) {
+    PaymentIntent? paymentIntent;
+    if (paymentIntentExpansion != null) {
+      paymentIntent = paymentIntentExpansion!.extract(object);
+    }
+
+    List<DiscountExpanded>? discounts;
+    if (discountsExpansion != null) {
+      discounts = discountsExpansion!.extract(object);
+    }
+
+    return InvoiceExpanded(
+      invoice: Invoice.fromJson(object),
+      paymentIntent: paymentIntent,
+      discounts: discounts,
+    );
+  }
+
+  @override
+  String replacement(InvoiceExpanded parsedValue) {
+    return parsedValue.invoice.id;
+  }
+}
diff --git a/lib/src/utils/expandable_fields/latest_invoice_expandable_field.dart b/lib/src/utils/expandable_fields/latest_invoice_expandable_field.dart
new file mode 100644
index 0000000..2214625
--- /dev/null
+++ b/lib/src/utils/expandable_fields/latest_invoice_expandable_field.dart
@@ -0,0 +1,16 @@
+import 'package:stripe/src/utils/expandable_fields/discounts_expandable_field.dart';
+import 'package:stripe/src/utils/expandable_fields/invoice_expandable_field.dart';
+import 'package:stripe/src/utils/expandable_fields/payment_intent_expandable_field.dart';
+
+class LatestInvoiceExpandableField extends InvoiceExpandableField {
+  @override
+  String get field => 'latest_invoice';
+
+  const LatestInvoiceExpandableField({
+    PaymentIntentExpandableField? paymentIntentExpansion,
+    DiscountsExpandableField? discountsExpansion,
+  }) : super(
+          paymentIntentExpansion: paymentIntentExpansion,
+          discountsExpansion: discountsExpansion,
+        );
+}
diff --git a/lib/src/utils/expandable_fields/latest_invoice_expanded_expandable_field.dart b/lib/src/utils/expandable_fields/latest_invoice_expanded_expandable_field.dart
deleted file mode 100644
index 2bfd161..0000000
--- a/lib/src/utils/expandable_fields/latest_invoice_expanded_expandable_field.dart
+++ /dev/null
@@ -1,25 +0,0 @@
-import 'package:stripe/src/expanded.dart';
-import 'package:stripe/src/messages/enums/expandable_fields/invoice_expandable_field.dart';
-import 'package:stripe/src/utils/expandable_object_field.dart';
-
-class LatestInvoiceExpandedExpandableField
-    extends ExpandableObjectField<InvoiceExpanded> {
-  final Set<InvoiceExpandableField> expand;
-
-  @override
-  String get field => 'latest_invoice';
-
-  const LatestInvoiceExpandedExpandableField({
-    required this.expand,
-  });
-
-  @override
-  InvoiceExpanded parse(Map<String, dynamic> object) {
-    return InvoiceExpanded.fromJson(object, expand);
-  }
-
-  @override
-  String replacement(InvoiceExpanded parsedValue) {
-    return parsedValue.invoice.id;
-  }
-}
diff --git a/lib/src/utils/expandable_fields/subscription_expandable_field.dart b/lib/src/utils/expandable_fields/subscription_expandable_field.dart
new file mode 100644
index 0000000..c3b0abd
--- /dev/null
+++ b/lib/src/utils/expandable_fields/subscription_expandable_field.dart
@@ -0,0 +1,61 @@
+import 'package:stripe/messages.dart';
+import 'package:stripe/src/expanded/customer_expanded.dart';
+import 'package:stripe/src/expanded/discount_expanded.dart';
+import 'package:stripe/src/expanded/invoice_expanded.dart';
+import 'package:stripe/src/expanded/subscription_expanded.dart';
+import 'package:stripe/src/utils/expandable_fields/customer_expandable_field.dart';
+import 'package:stripe/src/utils/expandable_fields/discounts_expandable_field.dart';
+import 'package:stripe/src/utils/expandable_fields/latest_invoice_expandable_field.dart';
+import 'package:stripe/src/utils/expandable_object_field.dart';
+
+class SubscriptionExpandableField
+    extends ExpandableObjectField<SubscriptionExpanded> {
+  final DiscountsExpandableField? discountsExpansion;
+  final LatestInvoiceExpandableField? latestInvoiceExpansion;
+  final CustomerExpandableField? customerExpansion;
+
+  const SubscriptionExpandableField({
+    this.discountsExpansion,
+    this.latestInvoiceExpansion,
+    this.customerExpansion,
+  });
+
+  @override
+  String get field => 'subscription';
+
+  @override
+  Iterable<String> get innerNestedFields => [
+        ...?customerExpansion?.nestedFields,
+        ...?latestInvoiceExpansion?.nestedFields,
+        ...?discountsExpansion?.nestedFields,
+      ];
+
+  @override
+  SubscriptionExpanded parse(Map<String, dynamic> object) {
+    List<DiscountExpanded>? discounts;
+    if (discountsExpansion != null) {
+      discounts = discountsExpansion!.extract(object);
+    }
+
+    InvoiceExpanded? latestInvoice;
+    if (latestInvoiceExpansion != null) {
+      latestInvoice = latestInvoiceExpansion!.extract(object);
+    }
+
+    CustomerExpanded? customer;
+    if (customerExpansion != null) {
+      customer = customerExpansion!.extract(object);
+    }
+
+    return SubscriptionExpanded(
+      subscription: Subscription.fromJson(object),
+      discounts: discounts,
+      latestInvoice: latestInvoice,
+      customer: customer,
+    );
+  }
+
+  @override
+  String replacement(SubscriptionExpanded parsedValue) =>
+      parsedValue.subscription.id;
+}
diff --git a/test/resources/expanded/subscription_expandable_field_test.dart b/test/resources/expanded/subscription_expandable_field_test.dart
new file mode 100644
index 0000000..7f304dd
--- /dev/null
+++ b/test/resources/expanded/subscription_expandable_field_test.dart
@@ -0,0 +1,39 @@
+import 'package:stripe/src/utils/expandable_fields/customer_expandable_field.dart';
+import 'package:stripe/src/utils/expandable_fields/discounts_expandable_field.dart';
+import 'package:stripe/src/utils/expandable_fields/latest_invoice_expandable_field.dart';
+import 'package:stripe/src/utils/expandable_fields/payment_intent_expandable_field.dart';
+import 'package:stripe/src/utils/expandable_fields/subscription_expandable_field.dart';
+import 'package:test/test.dart';
+
+void main() {
+  group('SubscriptionExpandableField', () {
+    const expansionSpec = SubscriptionExpandableField(
+      customerExpansion: CustomerExpandableField(),
+      discountsExpansion: DiscountsExpandableField(),
+      latestInvoiceExpansion: LatestInvoiceExpandableField(
+        discountsExpansion: DiscountsExpandableField(),
+        paymentIntentExpansion: PaymentIntentExpandableField(),
+      ),
+    );
+    test('Provides own expansion parameters correctly', () async {
+      expect(
+          expansionSpec.nestedFields.toSet(),
+          containsAll({
+            'subscription.latest_invoice.payment_intent',
+            'subscription.latest_invoice.discounts',
+            'subscription.customer',
+            'subscription.discounts',
+          }));
+    });
+    test('Provides nested expansion parameters correctly', () async {
+      expect(
+          expansionSpec.innerNestedFields.toSet(),
+          containsAll({
+            'latest_invoice.payment_intent',
+            'latest_invoice.discounts',
+            'customer',
+            'discounts',
+          }));
+    });
+  });
+}
diff --git a/test/resources/subscription/subscription_expanded_test.dart b/test/resources/subscription/subscription_expanded_test.dart
new file mode 100644
index 0000000..1ed4f85
--- /dev/null
+++ b/test/resources/subscription/subscription_expanded_test.dart
@@ -0,0 +1,662 @@
+import 'dart:convert';
+import 'dart:io';
+
+import 'package:dio/dio.dart';
+import 'package:stripe/src/client.dart';
+import 'package:stripe/src/expanded/discount_expanded.dart';
+import 'package:stripe/src/resources/subscription.dart';
+import 'package:stripe/src/utils/expandable_fields/customer_expandable_field.dart';
+import 'package:stripe/src/utils/expandable_fields/discounts_expandable_field.dart';
+import 'package:stripe/src/utils/expandable_fields/latest_invoice_expandable_field.dart';
+import 'package:stripe/src/utils/expandable_fields/payment_intent_expandable_field.dart';
+import 'package:stripe/src/utils/expandable_fields/subscription_expandable_field.dart';
+import 'package:test/test.dart';
+
+void main() {
+  late DioClient client;
+  late SubscriptionResource subscriptionResource;
+  setUp(() {
+    // We set the baseUrl to something unreachable, because we define
+    // interceptors in the tests.
+    client = DioClient(apiKey: 'sk_foobar', baseUrl: 'http://void/');
+    subscriptionResource = SubscriptionResource(client);
+  });
+  group('SubscriptionExpanded', () {
+    test('properly decodes all values', () async {
+      const subscriptionId = 'sub_testSubscriptionId';
+      final expansionSpec = SubscriptionExpandableField(
+        customerExpansion: CustomerExpandableField(),
+        discountsExpansion: DiscountsExpandableField(),
+        latestInvoiceExpansion: LatestInvoiceExpandableField(
+          discountsExpansion: DiscountsExpandableField(),
+          paymentIntentExpansion: PaymentIntentExpandableField(),
+        ),
+      );
+
+      client.dio.interceptors.add(InterceptorsWrapper(
+        onRequest: (options, handler) {
+          expect(options.method, 'GET');
+          expect(options.data, null);
+          expect(
+              options.queryParameters.values.toSet(),
+              containsAll({
+                'latest_invoice.payment_intent',
+                'latest_invoice.discounts',
+                'customer',
+                'discounts',
+              }));
+          handler.resolve(
+            Response(
+              requestOptions: options,
+              data: jsonDecode(retrieveExpandedSubscriptionResponse),
+              statusCode: HttpStatus.ok,
+            ),
+          );
+        },
+      ));
+
+      final subscriptionExpanded = await subscriptionResource.retrieveExpanded(
+        subscriptionId,
+        expand: expansionSpec,
+      );
+
+      final subscription = subscriptionExpanded.subscription;
+      expect(subscription.id, subscriptionId);
+      expect(subscription.items.data.length, 1);
+
+      final subscriptionItem = subscription.items.data.first;
+      expect(subscriptionItem.id, 'si_testSubscriptionItemId');
+      expect(subscriptionItem.price.id, 'price_testPlanPriceId');
+      expect(subscriptionItem.price.active, isTrue);
+
+      expect(
+        subscriptionExpanded.discounts,
+        isA<List<DiscountExpanded>>()
+            .having((l) => l.isEmpty, 'isEmpty', isTrue),
+      );
+
+      final customer = subscriptionExpanded.customer?.customer;
+      if (customer == null) fail('Customer is null');
+      expect(customer.id, 'cus_testCustomerId');
+      expect(customer.email, 'testmail@test.com');
+
+      final latestInvoice = subscriptionExpanded.latestInvoice?.invoice;
+      if (latestInvoice == null) fail('latestInvoice is null');
+      expect(latestInvoice.id, 'in_testInvoiceId');
+      expect(latestInvoice.accountName, 'A very profitable company');
+
+      final paymentIntent = subscriptionExpanded.latestInvoice?.paymentIntent;
+      if (paymentIntent == null) fail('latestInvoice.paymentIntent is null');
+      expect(paymentIntent.id, 'pi_testPaymentIntentId');
+      expect(paymentIntent.amount, 29900);
+
+      final invoiceDiscounts = subscriptionExpanded.latestInvoice?.discounts;
+      if (invoiceDiscounts == null) fail('latestInvoice.discounts is null');
+      expect(invoiceDiscounts, isEmpty);
+    });
+  });
+}
+
+const retrieveExpandedSubscriptionResponse = r'''
+{
+    "id": "sub_testSubscriptionId",
+    "object": "subscription",
+    "application": null,
+    "application_fee_percent": null,
+    "automatic_tax": {
+        "enabled": false,
+        "liability": null
+    },
+    "billing_cycle_anchor": 1727074800,
+    "billing_cycle_anchor_config": {
+        "day_of_month": 23,
+        "hour": 7,
+        "minute": 0,
+        "month": null,
+        "second": 0
+    },
+    "billing_thresholds": null,
+    "cancel_at": null,
+    "cancel_at_period_end": false,
+    "canceled_at": null,
+    "cancellation_details": {
+        "comment": null,
+        "feedback": null,
+        "reason": null
+    },
+    "collection_method": "charge_automatically",
+    "created": 1724414109,
+    "currency": "usd",
+    "current_period_end": 1727074800,
+    "current_period_start": 1724414109,
+    "customer": {
+        "id": "cus_testCustomerId",
+        "object": "customer",
+        "address": null,
+        "balance": 0,
+        "created": 1721299529,
+        "currency": "usd",
+        "default_currency": "usd",
+        "default_source": null,
+        "delinquent": false,
+        "description": null,
+        "discount": null,
+        "email": "testmail@test.com",
+        "invoice_prefix": "EADE9237",
+        "invoice_settings": {
+            "custom_fields": null,
+            "default_payment_method": "pm_testPaymentMethodId",
+            "footer": null,
+            "rendering_options": null
+        },
+        "livemode": false,
+        "metadata": {},
+        "name": "John Doe",
+        "next_invoice_sequence": 59,
+        "phone": null,
+        "preferred_locales": [],
+        "shipping": null,
+        "tax_exempt": "none",
+        "test_clock": null
+    },
+    "days_until_due": null,
+    "default_payment_method": null,
+    "default_source": null,
+    "default_tax_rates": [],
+    "description": null,
+    "discount": null,
+    "discounts": [],
+    "ended_at": null,
+    "invoice_settings": {
+        "account_tax_ids": null,
+        "issuer": {
+            "type": "self"
+        }
+    },
+    "items": {
+        "object": "list",
+        "data": [
+            {
+                "id": "si_testSubscriptionItemId",
+                "object": "subscription_item",
+                "billing_thresholds": null,
+                "created": 1724414109,
+                "discounts": [],
+                "metadata": {},
+                "plan": {
+                    "id": "price_testPlanPriceId",
+                    "object": "plan",
+                    "active": true,
+                    "aggregate_usage": null,
+                    "amount": 29900,
+                    "amount_decimal": "29900",
+                    "billing_scheme": "per_unit",
+                    "created": 1720570375,
+                    "currency": "usd",
+                    "interval": "month",
+                    "interval_count": 1,
+                    "livemode": false,
+                    "metadata": {},
+                    "meter": null,
+                    "nickname": null,
+                    "product": "prod_testProductId",
+                    "tiers_mode": null,
+                    "transform_usage": null,
+                    "trial_period_days": null,
+                    "usage_type": "licensed"
+                },
+                "price": {
+                    "id": "price_testPlanPriceId",
+                    "object": "price",
+                    "active": true,
+                    "billing_scheme": "per_unit",
+                    "created": 1720570375,
+                    "currency": "usd",
+                    "custom_unit_amount": null,
+                    "livemode": false,
+                    "lookup_key": null,
+                    "metadata": {},
+                    "nickname": null,
+                    "product": "prod_testProductId",
+                    "recurring": {
+                        "aggregate_usage": null,
+                        "interval": "month",
+                        "interval_count": 1,
+                        "meter": null,
+                        "trial_period_days": null,
+                        "usage_type": "licensed"
+                    },
+                    "tax_behavior": "unspecified",
+                    "tiers_mode": null,
+                    "transform_quantity": null,
+                    "type": "recurring",
+                    "unit_amount": 29900,
+                    "unit_amount_decimal": "29900"
+                },
+                "quantity": 1,
+                "subscription": "sub_testSubscriptionId",
+                "tax_rates": []
+            }
+        ],
+        "has_more": false,
+        "total_count": 1,
+        "url": "/v1/subscription_items?subscription=sub_testSubscriptionId"
+    },
+    "latest_invoice": {
+        "id": "in_testInvoiceId",
+        "object": "invoice",
+        "account_country": "US",
+        "account_name": "A very profitable company",
+        "account_tax_ids": null,
+        "amount_due": 29900,
+        "amount_paid": 29900,
+        "amount_remaining": 0,
+        "amount_shipping": 0,
+        "application": null,
+        "application_fee_amount": null,
+        "attempt_count": 1,
+        "attempted": true,
+        "auto_advance": false,
+        "automatic_tax": {
+            "enabled": false,
+            "liability": null,
+            "status": null
+        },
+        "automatically_finalizes_at": null,
+        "billing_reason": "subscription_create",
+        "charge": "ch_testChargeId",
+        "collection_method": "charge_automatically",
+        "created": 1724414109,
+        "currency": "usd",
+        "custom_fields": null,
+        "customer": "cus_testCustomerId",
+        "customer_address": null,
+        "customer_email": "testmail@test.com",
+        "customer_name": "John Doe",
+        "customer_phone": null,
+        "customer_shipping": null,
+        "customer_tax_exempt": "none",
+        "customer_tax_ids": [],
+        "default_payment_method": null,
+        "default_source": null,
+        "default_tax_rates": [],
+        "description": null,
+        "discount": null,
+        "discounts": [],
+        "due_date": null,
+        "effective_at": 1724414109,
+        "ending_balance": 0,
+        "footer": null,
+        "from_invoice": null,
+        "hosted_invoice_url": "https://void",
+        "invoice_pdf": "https://void",
+        "issuer": {
+            "type": "self"
+        },
+        "last_finalization_error": null,
+        "latest_revision": null,
+        "lines": {
+            "object": "list",
+            "data": [
+                {
+                    "id": "il_testLineItemId",
+                    "object": "line_item",
+                    "amount": 29900,
+                    "amount_excluding_tax": 29900,
+                    "currency": "usd",
+                    "description": "Time on a subscription plan from 23 Aug 2024 until 23 Sep 2024",
+                    "discount_amounts": [],
+                    "discountable": false,
+                    "discounts": [],
+                    "invoice": "in_testInvoiceId",
+                    "invoice_item": "ii_testInvoiceItemId",
+                    "livemode": false,
+                    "metadata": {},
+                    "period": {
+                        "end": 1727074800,
+                        "start": 1724396400
+                    },
+                    "plan": {
+                        "id": "price_testPlanPriceId",
+                        "object": "plan",
+                        "active": true,
+                        "aggregate_usage": null,
+                        "amount": 29900,
+                        "amount_decimal": "29900",
+                        "billing_scheme": "per_unit",
+                        "created": 1720570375,
+                        "currency": "usd",
+                        "interval": "month",
+                        "interval_count": 1,
+                        "livemode": false,
+                        "metadata": {},
+                        "meter": null,
+                        "nickname": null,
+                        "product": "prod_testProductId",
+                        "tiers_mode": null,
+                        "transform_usage": null,
+                        "trial_period_days": null,
+                        "usage_type": "licensed"
+                    },
+                    "price": {
+                        "id": "price_testPlanPriceId",
+                        "object": "price",
+                        "active": true,
+                        "billing_scheme": "per_unit",
+                        "created": 1720570375,
+                        "currency": "usd",
+                        "custom_unit_amount": null,
+                        "livemode": false,
+                        "lookup_key": null,
+                        "metadata": {},
+                        "nickname": null,
+                        "product": "prod_testProductId",
+                        "recurring": {
+                            "aggregate_usage": null,
+                            "interval": "month",
+                            "interval_count": 1,
+                            "meter": null,
+                            "trial_period_days": null,
+                            "usage_type": "licensed"
+                        },
+                        "tax_behavior": "unspecified",
+                        "tiers_mode": null,
+                        "transform_quantity": null,
+                        "type": "recurring",
+                        "unit_amount": 29900,
+                        "unit_amount_decimal": "29900"
+                    },
+                    "proration": true,
+                    "proration_details": {
+                        "credited_items": null
+                    },
+                    "quantity": 1,
+                    "subscription": "sub_testSubscriptionId",
+                    "subscription_item": "si_testSubscriptionItemId",
+                    "tax_amounts": [],
+                    "tax_rates": [],
+                    "type": "invoiceitem",
+                    "unit_amount_excluding_tax": "29900"
+                }
+            ],
+            "has_more": false,
+            "total_count": 1,
+            "url": "/v1/invoices/in_testInvoiceId/lines"
+        },
+        "livemode": false,
+        "metadata": {},
+        "next_payment_attempt": null,
+        "number": "XXXXXX-XXXX",
+        "on_behalf_of": null,
+        "paid": true,
+        "paid_out_of_band": false,
+        "payment_intent": {
+            "id": "pi_testPaymentIntentId",
+            "object": "payment_intent",
+            "amount": 29900,
+            "amount_capturable": 0,
+            "amount_details": {
+                "tip": {}
+            },
+            "amount_received": 29900,
+            "application": null,
+            "application_fee_amount": null,
+            "automatic_payment_methods": null,
+            "canceled_at": null,
+            "cancellation_reason": null,
+            "capture_method": "automatic",
+            "charges": {
+                "object": "list",
+                "data": [
+                    {
+                        "id": "ch_testChargeId",
+                        "object": "charge",
+                        "amount": 29900,
+                        "amount_captured": 29900,
+                        "amount_refunded": 0,
+                        "application": null,
+                        "application_fee": null,
+                        "application_fee_amount": null,
+                        "balance_transaction": "txn_testTransactionId",
+                        "billing_details": {
+                            "address": {
+                                "city": null,
+                                "country": "GE",
+                                "line1": null,
+                                "line2": null,
+                                "postal_code": null,
+                                "state": null
+                            },
+                            "email": null,
+                            "name": null,
+                            "phone": null
+                        },
+                        "calculated_statement_descriptor": "TEST.COM",
+                        "captured": true,
+                        "created": 1724414114,
+                        "currency": "usd",
+                        "customer": "cus_testCustomerId",
+                        "description": "Subscription creation",
+                        "destination": null,
+                        "dispute": null,
+                        "disputed": false,
+                        "failure_balance_transaction": null,
+                        "failure_code": null,
+                        "failure_message": null,
+                        "fraud_details": {},
+                        "invoice": "in_testInvoiceId",
+                        "livemode": false,
+                        "metadata": {},
+                        "on_behalf_of": null,
+                        "order": null,
+                        "outcome": {
+                            "network_status": "approved_by_network",
+                            "reason": null,
+                            "risk_level": "normal",
+                            "risk_score": 51,
+                            "seller_message": "Payment complete.",
+                            "type": "authorized"
+                        },
+                        "paid": true,
+                        "payment_intent": "pi_testPaymentIntentId",
+                        "payment_method": "pm_testPaymentMethodId",
+                        "payment_method_details": {
+                            "card": {
+                                "amount_authorized": 29900,
+                                "authorization_code": null,
+                                "brand": "visa",
+                                "checks": {
+                                    "address_line1_check": null,
+                                    "address_postal_code_check": null,
+                                    "cvc_check": null
+                                },
+                                "country": "US",
+                                "exp_month": 4,
+                                "exp_year": 2026,
+                                "extended_authorization": {
+                                    "status": "disabled"
+                                },
+                                "fingerprint": "testFingerprintId",
+                                "funding": "credit",
+                                "incremental_authorization": {
+                                    "status": "unavailable"
+                                },
+                                "installments": null,
+                                "last4": "4242",
+                                "mandate": null,
+                                "multicapture": {
+                                    "status": "unavailable"
+                                },
+                                "network": "visa",
+                                "network_token": {
+                                    "used": false
+                                },
+                                "overcapture": {
+                                    "maximum_amount_capturable": 29900,
+                                    "status": "unavailable"
+                                },
+                                "three_d_secure": null,
+                                "wallet": null
+                            },
+                            "type": "card"
+                        },
+                        "receipt_email": "testmail@test.com",
+                        "receipt_number": null,
+                        "receipt_url": "https://void",
+                        "refunded": false,
+                        "refunds": {
+                            "object": "list",
+                            "data": [],
+                            "has_more": false,
+                            "total_count": 0,
+                            "url": "/v1/charges/ch_testChargeId/refunds"
+                        },
+                        "review": null,
+                        "shipping": null,
+                        "source": null,
+                        "source_transfer": null,
+                        "statement_descriptor": null,
+                        "statement_descriptor_suffix": null,
+                        "status": "succeeded",
+                        "transfer_data": null,
+                        "transfer_group": null
+                    }
+                ],
+                "has_more": false,
+                "total_count": 1,
+                "url": "/v1/charges?payment_intent=pi_testPaymentIntentId"
+            },
+            "client_secret": "pi_testPaymentIntentId_secret_testSecret",
+            "confirmation_method": "automatic",
+            "created": 1724414109,
+            "currency": "usd",
+            "customer": "cus_testCustomerId",
+            "description": "Subscription creation",
+            "invoice": "in_testInvoiceId",
+            "last_payment_error": null,
+            "latest_charge": "ch_testChargeId",
+            "livemode": false,
+            "metadata": {},
+            "next_action": null,
+            "on_behalf_of": null,
+            "payment_method": "pm_testPaymentMethodId",
+            "payment_method_configuration_details": null,
+            "payment_method_options": {
+                "card": {
+                    "installments": null,
+                    "mandate_options": null,
+                    "network": null,
+                    "request_three_d_secure": "automatic"
+                }
+            },
+            "payment_method_types": [
+                "card"
+            ],
+            "processing": null,
+            "receipt_email": "testmail@test.com",
+            "review": null,
+            "setup_future_usage": "off_session",
+            "shipping": null,
+            "source": null,
+            "statement_descriptor": null,
+            "statement_descriptor_suffix": null,
+            "status": "succeeded",
+            "transfer_data": null,
+            "transfer_group": null
+        },
+        "payment_settings": {
+            "default_mandate": null,
+            "payment_method_options": null,
+            "payment_method_types": [
+                "card"
+            ]
+        },
+        "period_end": 1724414109,
+        "period_start": 1724414109,
+        "post_payment_credit_notes_amount": 0,
+        "pre_payment_credit_notes_amount": 0,
+        "quote": null,
+        "receipt_number": null,
+        "rendering": null,
+        "rendering_options": null,
+        "shipping_cost": null,
+        "shipping_details": null,
+        "starting_balance": 0,
+        "statement_descriptor": null,
+        "status": "paid",
+        "status_transitions": {
+            "finalized_at": 1724414109,
+            "marked_uncollectible_at": null,
+            "paid_at": 1724414115,
+            "voided_at": null
+        },
+        "subscription": "sub_testSubscriptionId",
+        "subscription_details": {
+            "metadata": {
+                "contract_id": "157"
+            }
+        },
+        "subtotal": 29900,
+        "subtotal_excluding_tax": 29900,
+        "tax": null,
+        "test_clock": null,
+        "total": 29900,
+        "total_discount_amounts": [],
+        "total_excluding_tax": 29900,
+        "total_tax_amounts": [],
+        "transfer_data": null,
+        "webhooks_delivered_at": 1724414111
+    },
+    "livemode": false,
+    "metadata": {
+        "contract_id": "157"
+    },
+    "next_pending_invoice_item_invoice": null,
+    "on_behalf_of": null,
+    "pause_collection": null,
+    "payment_settings": {
+        "payment_method_options": null,
+        "payment_method_types": [
+            "card"
+        ],
+        "save_default_payment_method": "off"
+    },
+    "pending_invoice_item_interval": null,
+    "pending_setup_intent": null,
+    "pending_update": null,
+    "plan": {
+        "id": "price_testPlanPriceId",
+        "object": "plan",
+        "active": true,
+        "aggregate_usage": null,
+        "amount": 29900,
+        "amount_decimal": "29900",
+        "billing_scheme": "per_unit",
+        "created": 1720570375,
+        "currency": "usd",
+        "interval": "month",
+        "interval_count": 1,
+        "livemode": false,
+        "metadata": {},
+        "meter": null,
+        "nickname": null,
+        "product": "prod_testProductId",
+        "tiers_mode": null,
+        "transform_usage": null,
+        "trial_period_days": null,
+        "usage_type": "licensed"
+    },
+    "quantity": 1,
+    "schedule": null,
+    "start_date": 1724396400,
+    "status": "active",
+    "test_clock": null,
+    "transfer_data": null,
+    "trial_end": null,
+    "trial_settings": {
+        "end_behavior": {
+            "missing_payment_method": "create_invoice"
+        }
+    },
+    "trial_start": null
+}''';
diff --git a/test/resources/subscription_test.dart b/test/resources/subscription/subscription_test.dart
similarity index 100%
rename from test/resources/subscription_test.dart
rename to test/resources/subscription/subscription_test.dart