diff --git a/backend/online-boutique/services/checkout/go.mod b/backend/online-boutique/services/checkout/go.mod
index f2b1ef2d..12a9ef32 100644
--- a/backend/online-boutique/services/checkout/go.mod
+++ b/backend/online-boutique/services/checkout/go.mod
@@ -5,7 +5,7 @@ go 1.21.6
 replace github.com/TBD54566975/ftl/examples/online-boutique => ../..
 
 require (
-	github.com/TBD54566975/ftl v0.99.0
+	github.com/TBD54566975/ftl v0.107.0
 	github.com/TBD54566975/ftl/examples/online-boutique v0.0.0-00010101000000-000000000000
 	github.com/google/uuid v1.5.0
 )
diff --git a/backend/online-boutique/services/checkout/go.sum b/backend/online-boutique/services/checkout/go.sum
index fd3ee3fb..b9fff7c4 100644
--- a/backend/online-boutique/services/checkout/go.sum
+++ b/backend/online-boutique/services/checkout/go.sum
@@ -4,10 +4,10 @@ connectrpc.com/grpcreflect v1.2.0 h1:Q6og1S7HinmtbEuBvARLNwYmTbhEGRpHDhqrPNlmK+U
 connectrpc.com/grpcreflect v1.2.0/go.mod h1:nwSOKmE8nU5u/CidgHtPYk1PFI3U9ignz7iDMxOYkSY=
 connectrpc.com/otelconnect v0.7.0 h1:ZH55ZZtcJOTKWWLy3qmL4Pam4RzRWBJFOqTPyAqCXkY=
 connectrpc.com/otelconnect v0.7.0/go.mod h1:Bt2ivBymHZHqxvo4HkJ0EwHuUzQN6k2l0oH+mp/8nwc=
-github.com/TBD54566975/ftl v0.99.0 h1:IBdJoPwajme+8EUwlLQPwT+aVgLWM4OibO3Dbamf80w=
-github.com/TBD54566975/ftl v0.99.0/go.mod h1:KJrJ1KFFWdXFoZghKYBkHbrCkUaQYfcLhFs9jOZ4mcc=
-github.com/alecthomas/assert/v2 v2.4.1 h1:mwPZod/d35nlaCppr6sFP0rbCL05WH9fIo7lvsf47zo=
-github.com/alecthomas/assert/v2 v2.4.1/go.mod h1:fw5suVxB+wfYJ3291t0hRTqtGzFYdSwstnRQdaQx2DM=
+github.com/TBD54566975/ftl v0.107.0 h1:zdeWEETDkcu+0onfgk/9IVsB5QPC++mv751fTVXePtA=
+github.com/TBD54566975/ftl v0.107.0/go.mod h1:7yRFD+2zC5zstcXYcSJzAubRi6MecQZndMnEbd1zMwM=
+github.com/alecthomas/assert/v2 v2.5.0 h1:OJKYg53BQx06/bMRBSPDCO49CbCDNiUQXwdoNrt6x5w=
+github.com/alecthomas/assert/v2 v2.5.0/go.mod h1:fw5suVxB+wfYJ3291t0hRTqtGzFYdSwstnRQdaQx2DM=
 github.com/alecthomas/concurrency v0.0.2 h1:Q3kGPtLbleMbH9lHX5OBFvJygfyFw29bXZKBg+IEVuo=
 github.com/alecthomas/concurrency v0.0.2/go.mod h1:GmuQb/iHX7mbNtPlC/WDzEFxDMB0HYFer2Qda9QTs7w=
 github.com/alecthomas/participle/v2 v2.1.1 h1:hrjKESvSqGHzRb4yW1ciisFJ4p3MGYih6icjJvbsmV8=
diff --git a/backend/online-boutique/services/recommendation/go.mod b/backend/online-boutique/services/recommendation/go.mod
index 98cb2547..aa070375 100644
--- a/backend/online-boutique/services/recommendation/go.mod
+++ b/backend/online-boutique/services/recommendation/go.mod
@@ -4,7 +4,7 @@ go 1.21.6
 
 replace github.com/TBD54566975/ftl/examples/online-boutique => ../..
 
-require github.com/TBD54566975/ftl v0.99.0
+require github.com/TBD54566975/ftl v0.107.0
 
 require (
 	connectrpc.com/connect v1.14.0 // indirect
diff --git a/backend/online-boutique/services/recommendation/go.sum b/backend/online-boutique/services/recommendation/go.sum
index fd3ee3fb..b9fff7c4 100644
--- a/backend/online-boutique/services/recommendation/go.sum
+++ b/backend/online-boutique/services/recommendation/go.sum
@@ -4,10 +4,10 @@ connectrpc.com/grpcreflect v1.2.0 h1:Q6og1S7HinmtbEuBvARLNwYmTbhEGRpHDhqrPNlmK+U
 connectrpc.com/grpcreflect v1.2.0/go.mod h1:nwSOKmE8nU5u/CidgHtPYk1PFI3U9ignz7iDMxOYkSY=
 connectrpc.com/otelconnect v0.7.0 h1:ZH55ZZtcJOTKWWLy3qmL4Pam4RzRWBJFOqTPyAqCXkY=
 connectrpc.com/otelconnect v0.7.0/go.mod h1:Bt2ivBymHZHqxvo4HkJ0EwHuUzQN6k2l0oH+mp/8nwc=
-github.com/TBD54566975/ftl v0.99.0 h1:IBdJoPwajme+8EUwlLQPwT+aVgLWM4OibO3Dbamf80w=
-github.com/TBD54566975/ftl v0.99.0/go.mod h1:KJrJ1KFFWdXFoZghKYBkHbrCkUaQYfcLhFs9jOZ4mcc=
-github.com/alecthomas/assert/v2 v2.4.1 h1:mwPZod/d35nlaCppr6sFP0rbCL05WH9fIo7lvsf47zo=
-github.com/alecthomas/assert/v2 v2.4.1/go.mod h1:fw5suVxB+wfYJ3291t0hRTqtGzFYdSwstnRQdaQx2DM=
+github.com/TBD54566975/ftl v0.107.0 h1:zdeWEETDkcu+0onfgk/9IVsB5QPC++mv751fTVXePtA=
+github.com/TBD54566975/ftl v0.107.0/go.mod h1:7yRFD+2zC5zstcXYcSJzAubRi6MecQZndMnEbd1zMwM=
+github.com/alecthomas/assert/v2 v2.5.0 h1:OJKYg53BQx06/bMRBSPDCO49CbCDNiUQXwdoNrt6x5w=
+github.com/alecthomas/assert/v2 v2.5.0/go.mod h1:fw5suVxB+wfYJ3291t0hRTqtGzFYdSwstnRQdaQx2DM=
 github.com/alecthomas/concurrency v0.0.2 h1:Q3kGPtLbleMbH9lHX5OBFvJygfyFw29bXZKBg+IEVuo=
 github.com/alecthomas/concurrency v0.0.2/go.mod h1:GmuQb/iHX7mbNtPlC/WDzEFxDMB0HYFer2Qda9QTs7w=
 github.com/alecthomas/participle/v2 v2.1.1 h1:hrjKESvSqGHzRb4yW1ciisFJ4p3MGYih6icjJvbsmV8=
diff --git a/frontend/mobile/lib/api/ad.dart b/frontend/mobile/lib/api/ad.dart
index fb87f2f6..0d2c9bb6 100644
--- a/frontend/mobile/lib/api/ad.dart
+++ b/frontend/mobile/lib/api/ad.dart
@@ -6,7 +6,7 @@ import 'dart:typed_data';
 import 'ftl_client.dart';
 
 
-class AdRequest {
+class AdRequest{
   List<String> contextKeys;
 
   AdRequest({  required this.contextKeys,  });
@@ -28,7 +28,7 @@ class AdRequest {
   factory AdRequest.fromJson(String source) => AdRequest.fromMap(json.decode(source));
 }
 
-class Ad {
+class Ad{
   String redirectURL;
   String text;
 
@@ -53,7 +53,7 @@ class Ad {
   factory Ad.fromJson(String source) => Ad.fromMap(json.decode(source));
 }
 
-class AdResponse {
+class AdResponse{
   String name;
   List<Ad> ads;
 
diff --git a/frontend/mobile/lib/api/builtin.dart b/frontend/mobile/lib/api/builtin.dart
index 48c6b301..0bbd7c13 100644
--- a/frontend/mobile/lib/api/builtin.dart
+++ b/frontend/mobile/lib/api/builtin.dart
@@ -6,13 +6,13 @@ import 'dart:typed_data';
 import 'ftl_client.dart';
 
 
-class HttpRequest {
+class HttpRequest<Body>{
   String method;
   String path;
   Map<String, String> pathParameters;
   Map<String, List<String>> query;
   Map<String, List<String>> headers;
-  Uint8List body;
+  Body body;
 
   HttpRequest({  required this.method,  required this.path,  required this.pathParameters,  required this.query,  required this.headers,  required this.body,  });
 
@@ -43,10 +43,10 @@ class HttpRequest {
   factory HttpRequest.fromJson(String source) => HttpRequest.fromMap(json.decode(source));
 }
 
-class HttpResponse {
+class HttpResponse<Body>{
   int status;
   Map<String, List<String>> headers;
-  Uint8List body;
+  Body body;
 
   HttpResponse({  required this.status,  required this.headers,  required this.body,  });
 
diff --git a/frontend/mobile/lib/api/cart.dart b/frontend/mobile/lib/api/cart.dart
index 02f088c1..f35dcac1 100644
--- a/frontend/mobile/lib/api/cart.dart
+++ b/frontend/mobile/lib/api/cart.dart
@@ -6,7 +6,7 @@ import 'dart:typed_data';
 import 'ftl_client.dart';
 
 
-class Item {
+class Item{
   String productID;
   int quantity;
 
@@ -31,7 +31,7 @@ class Item {
   factory Item.fromJson(String source) => Item.fromMap(json.decode(source));
 }
 
-class AddItemRequest {
+class AddItemRequest{
   String userID;
   Item item;
 
@@ -56,7 +56,7 @@ class AddItemRequest {
   factory AddItemRequest.fromJson(String source) => AddItemRequest.fromMap(json.decode(source));
 }
 
-class AddItemResponse {
+class AddItemResponse{
 
   AddItemResponse();
 
@@ -75,7 +75,7 @@ class AddItemResponse {
   factory AddItemResponse.fromJson(String source) => AddItemResponse.fromMap(json.decode(source));
 }
 
-class GetCartRequest {
+class GetCartRequest{
   String userID;
 
   GetCartRequest({  required this.userID,  });
@@ -97,7 +97,7 @@ class GetCartRequest {
   factory GetCartRequest.fromJson(String source) => GetCartRequest.fromMap(json.decode(source));
 }
 
-class Cart {
+class Cart{
   String userID;
   List<Item> items;
 
@@ -122,7 +122,7 @@ class Cart {
   factory Cart.fromJson(String source) => Cart.fromMap(json.decode(source));
 }
 
-class EmptyCartRequest {
+class EmptyCartRequest{
   String userID;
 
   EmptyCartRequest({  required this.userID,  });
@@ -144,7 +144,7 @@ class EmptyCartRequest {
   factory EmptyCartRequest.fromJson(String source) => EmptyCartRequest.fromMap(json.decode(source));
 }
 
-class EmptyCartResponse {
+class EmptyCartResponse{
 
   EmptyCartResponse();
 
diff --git a/frontend/mobile/lib/api/checkout.dart b/frontend/mobile/lib/api/checkout.dart
index 740894cc..6cdd5750 100644
--- a/frontend/mobile/lib/api/checkout.dart
+++ b/frontend/mobile/lib/api/checkout.dart
@@ -11,7 +11,7 @@ import 'productcatalog.dart' as productcatalog;
 import 'shipping.dart' as shipping;
 
 
-class PlaceOrderRequest {
+class PlaceOrderRequest{
   String userID;
   String userCurrency;
   shipping.Address address;
@@ -45,7 +45,7 @@ class PlaceOrderRequest {
   factory PlaceOrderRequest.fromJson(String source) => PlaceOrderRequest.fromMap(json.decode(source));
 }
 
-class OrderItem {
+class OrderItem{
   cart.Item item;
   currency.Money cost;
 
@@ -70,7 +70,7 @@ class OrderItem {
   factory OrderItem.fromJson(String source) => OrderItem.fromMap(json.decode(source));
 }
 
-class Order {
+class Order{
   String id;
   String shippingTrackingID;
   currency.Money shippingCost;
diff --git a/frontend/mobile/lib/api/currency.dart b/frontend/mobile/lib/api/currency.dart
index ac7e0e5a..4393e386 100644
--- a/frontend/mobile/lib/api/currency.dart
+++ b/frontend/mobile/lib/api/currency.dart
@@ -6,7 +6,7 @@ import 'dart:typed_data';
 import 'ftl_client.dart';
 
 
-class GetSupportedCurrenciesRequest {
+class GetSupportedCurrenciesRequest{
 
   GetSupportedCurrenciesRequest();
 
@@ -25,7 +25,7 @@ class GetSupportedCurrenciesRequest {
   factory GetSupportedCurrenciesRequest.fromJson(String source) => GetSupportedCurrenciesRequest.fromMap(json.decode(source));
 }
 
-class GetSupportedCurrenciesResponse {
+class GetSupportedCurrenciesResponse{
   List<String> currencyCodes;
 
   GetSupportedCurrenciesResponse({  required this.currencyCodes,  });
@@ -47,7 +47,7 @@ class GetSupportedCurrenciesResponse {
   factory GetSupportedCurrenciesResponse.fromJson(String source) => GetSupportedCurrenciesResponse.fromMap(json.decode(source));
 }
 
-class Money {
+class Money{
   String currencyCode;
   int units;
   int nanos;
@@ -75,7 +75,7 @@ class Money {
   factory Money.fromJson(String source) => Money.fromMap(json.decode(source));
 }
 
-class ConvertRequest {
+class ConvertRequest{
   Money from;
   String toCode;
 
diff --git a/frontend/mobile/lib/api/payment.dart b/frontend/mobile/lib/api/payment.dart
index f6d0b795..efeb2ce4 100644
--- a/frontend/mobile/lib/api/payment.dart
+++ b/frontend/mobile/lib/api/payment.dart
@@ -7,7 +7,7 @@ import 'ftl_client.dart';
 import 'currency.dart' as currency;
 
 
-class CreditCardInfo {
+class CreditCardInfo{
   String number;
   int cVV;
   int expirationYear;
@@ -38,7 +38,7 @@ class CreditCardInfo {
   factory CreditCardInfo.fromJson(String source) => CreditCardInfo.fromMap(json.decode(source));
 }
 
-class ChargeRequest {
+class ChargeRequest{
   currency.Money amount;
   CreditCardInfo creditCard;
 
@@ -63,7 +63,7 @@ class ChargeRequest {
   factory ChargeRequest.fromJson(String source) => ChargeRequest.fromMap(json.decode(source));
 }
 
-class ChargeResponse {
+class ChargeResponse{
   String transactionID;
 
   ChargeResponse({  required this.transactionID,  });
diff --git a/frontend/mobile/lib/api/productcatalog.dart b/frontend/mobile/lib/api/productcatalog.dart
index f25aaae4..539d50ce 100644
--- a/frontend/mobile/lib/api/productcatalog.dart
+++ b/frontend/mobile/lib/api/productcatalog.dart
@@ -7,7 +7,7 @@ import 'ftl_client.dart';
 import 'currency.dart' as currency;
 
 
-class ListRequest {
+class ListRequest{
 
   ListRequest();
 
@@ -26,7 +26,7 @@ class ListRequest {
   factory ListRequest.fromJson(String source) => ListRequest.fromMap(json.decode(source));
 }
 
-class Product {
+class Product{
   String id;
   String name;
   String description;
@@ -63,7 +63,7 @@ class Product {
   factory Product.fromJson(String source) => Product.fromMap(json.decode(source));
 }
 
-class ListResponse {
+class ListResponse{
   List<Product> products;
 
   ListResponse({  required this.products,  });
@@ -85,7 +85,7 @@ class ListResponse {
   factory ListResponse.fromJson(String source) => ListResponse.fromMap(json.decode(source));
 }
 
-class GetRequest {
+class GetRequest{
   String id;
 
   GetRequest({  required this.id,  });
@@ -107,7 +107,7 @@ class GetRequest {
   factory GetRequest.fromJson(String source) => GetRequest.fromMap(json.decode(source));
 }
 
-class SearchRequest {
+class SearchRequest{
   String query;
 
   SearchRequest({  required this.query,  });
@@ -129,7 +129,7 @@ class SearchRequest {
   factory SearchRequest.fromJson(String source) => SearchRequest.fromMap(json.decode(source));
 }
 
-class SearchResponse {
+class SearchResponse{
   List<Product> results;
 
   SearchResponse({  required this.results,  });
diff --git a/frontend/mobile/lib/api/recommendation.dart b/frontend/mobile/lib/api/recommendation.dart
index 84739cdc..183950f2 100644
--- a/frontend/mobile/lib/api/recommendation.dart
+++ b/frontend/mobile/lib/api/recommendation.dart
@@ -7,7 +7,7 @@ import 'ftl_client.dart';
 import 'productcatalog.dart' as productcatalog;
 
 
-class ListRequest {
+class ListRequest{
   String userID;
   List<String> userProductIDs;
 
@@ -32,7 +32,7 @@ class ListRequest {
   factory ListRequest.fromJson(String source) => ListRequest.fromMap(json.decode(source));
 }
 
-class ListResponse {
+class ListResponse{
   List<String> productIDs;
 
   ListResponse({  required this.productIDs,  });
diff --git a/frontend/mobile/lib/api/shipping.dart b/frontend/mobile/lib/api/shipping.dart
index b2b1bf6b..980c6244 100644
--- a/frontend/mobile/lib/api/shipping.dart
+++ b/frontend/mobile/lib/api/shipping.dart
@@ -8,7 +8,7 @@ import 'cart.dart' as cart;
 import 'currency.dart' as currency;
 
 
-class Address {
+class Address{
   String streetAddress;
   String city;
   String state;
@@ -42,7 +42,7 @@ class Address {
   factory Address.fromJson(String source) => Address.fromMap(json.decode(source));
 }
 
-class ShippingRequest {
+class ShippingRequest{
   Address address;
   List<cart.Item> items;
 
@@ -67,7 +67,7 @@ class ShippingRequest {
   factory ShippingRequest.fromJson(String source) => ShippingRequest.fromMap(json.decode(source));
 }
 
-class ShipOrderResponse {
+class ShipOrderResponse{
   String id;
 
   ShipOrderResponse({  required this.id,  });
diff --git a/frontend/mobile/templates/template.js b/frontend/mobile/templates/template.js
index 5279d517..14fa1234 100644
--- a/frontend/mobile/templates/template.js
+++ b/frontend/mobile/templates/template.js
@@ -31,8 +31,14 @@ function dartType(t) {
       if (context.name === t.module) {
         return t.name;
       }
+      if (t.typeParameters && t.typeParameters.length > 0) {
+        return `${t.module}.${t.name}${dartTypeParameters(t.typeParameters)}`
+      }
       return `${t.module}.${t.name}`;
 
+    case "TypeParameter":
+      return t.name;
+
     case "Optional":
       return dartType(t.type) + "?";
 
@@ -41,6 +47,14 @@ function dartType(t) {
   }
 }
 
+function dartTypeParameters (t) {
+  if (t.length == 0) {
+    return "";
+  }
+
+  return `<${t.map((p) => dartType(p)).join(", ")}>`;
+}
+
 function deserialize(t) {
   switch (typename(t)) {
     case "Array":
diff --git a/frontend/mobile/templates/{{ .Name | lower }}.dart b/frontend/mobile/templates/{{ .Name | lower }}.dart
index fdd259ff..7de2acf5 100644
--- a/frontend/mobile/templates/{{ .Name | lower }}.dart	
+++ b/frontend/mobile/templates/{{ .Name | lower }}.dart	
@@ -9,7 +9,7 @@ import '{{. | lower }}.dart' as {{. | lower}};
 {{- end}}
 
 {{ range .Data }}
-class {{ .Name | camel }} {
+class {{ .Name | camel }}{{ .TypeParameters | dartTypeParameters }}{
 {{- range .Fields }}
   {{ .Type | dartType }} {{ .Name }};
 {{- end }}
diff --git a/frontend/web/src/api/builtin.ts b/frontend/web/src/api/builtin.ts
index a3c8f2cd..0dc40930 100644
--- a/frontend/web/src/api/builtin.ts
+++ b/frontend/web/src/api/builtin.ts
@@ -9,19 +9,19 @@
 //  /_/   /_/ /____/            
 //
 //
-export interface HttpRequest {
+export interface HttpRequest<Body> {
   method: string;
   path: string;
   pathParameters: Map<string, string>;
   query: Map<string, string[]>;
   headers: Map<string, string[]>;
-  body: Uint8Array;
+  body: Body;
 }
 
-export interface HttpResponse {
+export interface HttpResponse<Body> {
   status: number;
   headers: Map<string, string[]>;
-  body: Uint8Array;
+  body: Body;
 }
 
 
diff --git a/frontend/web/templates/template.js b/frontend/web/templates/template.js
index 87bde6e1..7638fa70 100644
--- a/frontend/web/templates/template.js
+++ b/frontend/web/templates/template.js
@@ -31,16 +31,30 @@ function tsType(t) {
       if (context.name === t.module) {
         return t.name
       }
+      if (t.typeParameters && t.typeParameters.length > 0) {
+        return `${t.module}.${t.name}${tsTypeParameters(t.typeParameters)}`
+      }
       return `${t.module}.${t.name}`
 
     case 'Optional':
       return tsType(t.type) + '?'
 
+    case "TypeParameter":
+      return t.name;
+
     default:
       throw new Error(`Unspported FTL type: ${typename(t)}`)
   }
 }
 
+function tsTypeParameters (t) {
+  if (t.length == 0) {
+    return "";
+  }
+
+  return `<${t.map((p) => tsType(p)).join(", ")}>`;
+}
+
 function deserialize(t) {
   switch (typename(t)) {
     case 'Array':
diff --git a/frontend/web/templates/{{ .Name | lower }}.ts b/frontend/web/templates/{{ .Name | lower }}.ts
index 2b2117e2..090850bb 100644
--- a/frontend/web/templates/{{ .Name | lower }}.ts	
+++ b/frontend/web/templates/{{ .Name | lower }}.ts	
@@ -15,7 +15,7 @@ import * as {{. | lower }} from "./{{. | lower}}"
 {{- end}}
 
 {{- range .Data }}
-export interface {{ .Name | camel }} {
+export interface {{ .Name | camel }}{{ .TypeParameters | tsTypeParameters }} {
 {{- range .Fields }}
   {{ .Name }}: {{ .Type | tsType }};
 {{- end }}