diff --git a/package.json b/package.json
index 18be04a..6453aca 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@updatedev/js",
-  "version": "0.4.1",
+  "version": "0.4.2",
   "description": "Update JavaScript SDK",
   "main": "dist/cjs/index.js",
   "module": "dist/esm/index.js",
diff --git a/src/UpdateBilling.ts b/src/UpdateBilling.ts
index 8335f02..0221e7a 100644
--- a/src/UpdateBilling.ts
+++ b/src/UpdateBilling.ts
@@ -145,7 +145,7 @@ export class UpdateBillingClient {
 
   async createCheckoutSession(
     id: string,
-    options?: CreateCheckoutSessionOptions
+    options: CreateCheckoutSessionOptions
   ): Promise<CreateCheckoutSession> {
     if (!this.hasSessionToken) {
       console.warn(
diff --git a/src/types/billing.ts b/src/types/billing.ts
index b304174..c112241 100644
--- a/src/types/billing.ts
+++ b/src/types/billing.ts
@@ -91,5 +91,6 @@ export type UpdateSubscriptionResponse = {
 };
 
 export type CreateCheckoutSessionOptions = {
-  redirect_url?: string;
+  redirect_url: string;
+  quantity?: number;
 };