diff --git a/plugin/plugin.xml b/plugin/plugin.xml
index 5fd3087..e66de1f 100644
--- a/plugin/plugin.xml
+++ b/plugin/plugin.xml
@@ -57,7 +57,7 @@
                 <param name="android-package" value="com.qonversion.android.sdk.QonversionPlugin"/>
             </feature>
         </config-file>
-        <framework src="io.qonversion.sandwich:sandwich:5.1.2" />
+        <framework src="io.qonversion.sandwich:sandwich:5.1.3" />
         <source-file src="src/android/QonversionPlugin.java" target-dir="src/com/qonversion/android/sdk" />
         <source-file src="src/android/EntitiesConverter.java" target-dir="src/com/qonversion/android/sdk" />
         <source-file src="src/android/Utils.java" target-dir="src/com/qonversion/android/sdk" />
@@ -75,7 +75,7 @@
                 <source url="https://github.com/CocoaPods/Specs.git"/>
             </config>
             <pods use-frameworks="true">
-                <pod name="QonversionSandwich" spec="5.1.2" />
+                <pod name="QonversionSandwich" spec="5.1.3" />
             </pods>
         </podspec>
     </platform>
diff --git a/plugin/src/android/QonversionPlugin.java b/plugin/src/android/QonversionPlugin.java
index 6d780a3..8684722 100644
--- a/plugin/src/android/QonversionPlugin.java
+++ b/plugin/src/android/QonversionPlugin.java
@@ -90,7 +90,10 @@ public void purchase(
             CallbackContext callbackContext
     ) {
         try {
-            List<String> contextKeysList = EntitiesConverter.convertArrayToStringList(contextKeys);
+            List<String> contextKeysList = contextKeys == null
+                ? null
+                : EntitiesConverter.convertArrayToStringList(contextKeys);
+
             qonversionSandwich.purchase(
                     productId,
                     offerId,
diff --git a/plugin/src/plugin/QonversionApi.ts b/plugin/src/plugin/QonversionApi.ts
index 6d3c796..85b6208 100644
--- a/plugin/src/plugin/QonversionApi.ts
+++ b/plugin/src/plugin/QonversionApi.ts
@@ -35,7 +35,7 @@ export interface QonversionApi {
    *
    * @see [Making Purchases](https://documentation.qonversion.io/docs/making-purchases)
    */
-  purchaseProduct(product: Product, options: PurchaseOptions): Promise<Map<string, Entitlement>>
+  purchaseProduct(product: Product, options: PurchaseOptions | undefined): Promise<Map<string, Entitlement>>
 
   /**
    * Make a purchase and validate it through server-to-server using Qonversion's Backend.
diff --git a/plugin/src/plugin/QonversionInternal.ts b/plugin/src/plugin/QonversionInternal.ts
index 8332d97..c32b434 100644
--- a/plugin/src/plugin/QonversionInternal.ts
+++ b/plugin/src/plugin/QonversionInternal.ts
@@ -25,7 +25,8 @@ import {RemoteConfigList} from "./RemoteConfigList";
 import {UserProperties} from './UserProperties';
 import {PurchaseModel} from './PurchaseModel';
 import {PurchaseUpdateModel} from './PurchaseUpdateModel';
-import {PurchaseOptions} from "./PurchaseOptions";;
+import {PurchaseOptions} from "./PurchaseOptions";
+import {PurchaseOptionsBuilder} from './PurchaseOptionsBuilder';
 
 const sdkVersion = "6.1.0";
 
@@ -63,8 +64,12 @@ export default class QonversionInternal implements QonversionApi {
     }
   }
 
-  async purchaseProduct(product: Product, options: PurchaseOptions): Promise<Map<string, Entitlement>> {
+  async purchaseProduct(product: Product, options: PurchaseOptions | undefined): Promise<Map<string, Entitlement>> {
     try {
+      if (!options) {
+        options = new PurchaseOptionsBuilder().build();
+      }
+
       let args: any[] = [product.qonversionID]
       if (isIos()) {
         args = [...args, options.quantity, options.contextKeys];
diff --git a/sample/www/js/index.js b/sample/www/js/index.js
index 9b1be45..eae1166 100644
--- a/sample/www/js/index.js
+++ b/sample/www/js/index.js
@@ -78,8 +78,8 @@ const app = {
         const products = await Qonversion.getSharedInstance().products();
         const product = products.get(productId);
         try {
-            const purchaseModel = product.toPurchaseModel(offerId);
-            const entitlements = await Qonversion.getSharedInstance().purchase(purchaseModel);
+            const purchaseOptions = !!offerId ? new Qonversion.PurchaseOptionsBuilder().setOfferId(offerId) : undefined;
+            const entitlements = await Qonversion.getSharedInstance().purchaseProduct(product, purchaseOptions);
             console.log('Qonversion purchase:', entitlements, productId);
         } catch (e) {
             console.log('Qonversion purchase failed', e);
diff --git a/sample/yarn.lock b/sample/yarn.lock
index e5dab6e..7609366 100644
--- a/sample/yarn.lock
+++ b/sample/yarn.lock
@@ -184,7 +184,7 @@ cordova-plugin-device@^3.0.0:
   integrity sha512-g8fFYOvleeYpklWvHwZ/T8/IzJe/3O0MGVDIUoqBru4v8SNDAbNVD3oOqoOQANBWGFQMg7GIkAAl8errCHZ7zQ==
 
 "cordova-plugin-qonversion@file:../plugin":
-  version "6.0.1"
+  version "6.1.0"
   resolved "file:../plugin"
 
 cross-spawn@^7.0.1, cross-spawn@^7.0.3:
@@ -276,7 +276,17 @@ fs-extra@^10.1.0:
     jsonfile "^6.0.1"
     universalify "^2.0.0"
 
-fs-extra@^9.0.0, fs-extra@^9.1.0:
+fs-extra@^9.0.0:
+  version "9.1.0"
+  resolved "https://registry.npmjs.org/fs-extra/-/fs-extra-9.1.0.tgz"
+  integrity sha512-hcg3ZmepS30/7BSFqRvoo3DOMQu7IjqxO5nCDt+zM9XWjb33Wg7ziNT+Qvqbuc3+gWpzO02JubVyk2G4Zvo1OQ==
+  dependencies:
+    at-least-node "^1.0.0"
+    graceful-fs "^4.2.0"
+    jsonfile "^6.0.1"
+    universalify "^2.0.0"
+
+fs-extra@^9.1.0:
   version "9.1.0"
   resolved "https://registry.npmjs.org/fs-extra/-/fs-extra-9.1.0.tgz"
   integrity sha512-hcg3ZmepS30/7BSFqRvoo3DOMQu7IjqxO5nCDt+zM9XWjb33Wg7ziNT+Qvqbuc3+gWpzO02JubVyk2G4Zvo1OQ==
@@ -365,10 +375,10 @@ ios-sim@^8.0.2:
     plist "^3.0.1"
     simctl "^2"
 
-is-core-module@^2.11.0:
-  version "2.12.1"
-  resolved "https://registry.npmjs.org/is-core-module/-/is-core-module-2.12.1.tgz"
-  integrity sha512-Q4ZuBAe2FUsKtyQJoQHlvP8OvBERxO3jEmy1I7hcRXcJBGGHFh/aJBswbXuS9sgrDH2QUO8ilkwNPHvHMd8clg==
+is-core-module@^2.13.0:
+  version "2.13.0"
+  resolved "https://registry.npmjs.org/is-core-module/-/is-core-module-2.13.0.tgz"
+  integrity sha512-Z7dk6Qo8pOCp3l4tsX2C5ZVas4V+UxwQodwZhLopL91TX8UyyHEXafPcyoeeWuLrwzHcr3igO78wNLwHJHsMCQ==
   dependencies:
     has "^1.0.3"
 
@@ -571,11 +581,11 @@ rechoir@^0.6.2:
     resolve "^1.1.6"
 
 resolve@^1.1.6:
-  version "1.22.2"
-  resolved "https://registry.npmjs.org/resolve/-/resolve-1.22.2.tgz"
-  integrity sha512-Sb+mjNHOULsBv818T40qSPeRiuWLyaGMa5ewydRLFimneixmVy2zdivRl+AF6jaYPC8ERxGDmFSiqui6SfPd+g==
+  version "1.22.4"
+  resolved "https://registry.npmjs.org/resolve/-/resolve-1.22.4.tgz"
+  integrity sha512-PXNdCiPqDqeUou+w1C2eTQbNfxKSuMxqTCuvlmmMsk1NWHL5fRrhY6Pl0qEYYc6+QqGClco1Qj8XnjPego4wfg==
   dependencies:
-    is-core-module "^2.11.0"
+    is-core-module "^2.13.0"
     path-parse "^1.0.7"
     supports-preserve-symlinks-flag "^1.0.0"