diff --git a/example/convex/_generated/api.d.ts b/example/convex/_generated/api.d.ts
index ba7e3d7..0858add 100644
--- a/example/convex/_generated/api.d.ts
+++ b/example/convex/_generated/api.d.ts
@@ -96,7 +96,6 @@ export declare const components: {
         "mutation",
         "internal",
         {
-          callback?: string;
           subscription: {
             amount: number | null;
             cancelAtPeriodEnd: boolean;
@@ -204,6 +203,12 @@ export declare const components: {
           userId: string;
         } | null
       >;
+      insertCustomer: FunctionReference<
+        "mutation",
+        "internal",
+        { id: string; userId: string },
+        string
+      >;
       listProducts: FunctionReference<
         "query",
         "internal",
diff --git a/example/convex/example.ts b/example/convex/example.ts
index e4523cd..4036c73 100644
--- a/example/convex/example.ts
+++ b/example/convex/example.ts
@@ -11,10 +11,15 @@ export const MAX_FREE_TODOS = 3;
 export const MAX_PREMIUM_TODOS = 6;
 
 export const { generateCheckoutLink } = polar.checkoutApi({
+  products: {
+    premium: "5fde8344-5fca-4d0b-adeb-2052cddfd9ed",
+    premiumPlus: "db548a6f-ff8c-4969-8f02-5f7301a36e7c",
+  },
   getUserInfo: async (ctx) => {
     const user = await ctx.runQuery(api.example.getCurrentUser);
     return {
       userId: user._id,
+      email: user.email,
     };
   },
 });
diff --git a/example/convex/seed.ts b/example/convex/seed.ts
index 199014f..747a774 100644
--- a/example/convex/seed.ts
+++ b/example/convex/seed.ts
@@ -58,6 +58,7 @@ const seed = internalAction({
         recurringInterval: "month",
         prices: [
           {
+            amountType: "fixed",
             priceAmount: 1000,
           },
         ],
@@ -68,6 +69,7 @@ const seed = internalAction({
         recurringInterval: "year",
         prices: [
           {
+            amountType: "fixed",
             priceAmount: 10000,
           },
         ],
@@ -78,6 +80,7 @@ const seed = internalAction({
         recurringInterval: "month",
         prices: [
           {
+            amountType: "fixed",
             priceAmount: 2000,
           },
         ],
@@ -88,6 +91,7 @@ const seed = internalAction({
         recurringInterval: "year",
         prices: [
           {
+            amountType: "fixed",
             priceAmount: 20000,
           },
         ],
diff --git a/example/src/UpgradeCta.tsx b/example/src/UpgradeCta.tsx
index 3c61447..f93b779 100644
--- a/example/src/UpgradeCta.tsx
+++ b/example/src/UpgradeCta.tsx
@@ -74,10 +74,7 @@ export function UpgradeCTA({
             </li>
           </ul>
           {!isPremium && !isPremiumPlus && (
-            <CheckoutLink
-              polarApi={api.example}
-              productId="2d368710-520b-49b0-ba7b-9c2d60d7b1c2"
-            >
+            <CheckoutLink polarApi={api.example} productKey="premium">
               <Button
                 variant="secondary"
                 className="w-full bg-white text-indigo-700 hover:bg-gray-100 dark:bg-gray-800 dark:text-indigo-300 dark:hover:bg-gray-700"
@@ -142,10 +139,7 @@ export function UpgradeCTA({
             </li>
           </ul>
           {!isPremiumPlus && (
-            <CheckoutLink
-              polarApi={api.example}
-              productId="premium-plus-product-id"
-            >
+            <CheckoutLink polarApi={api.example} productKey="premiumPlus">
               <Button
                 variant="secondary"
                 className="w-full bg-white/95 backdrop-blur-sm text-purple-700 hover:bg-white dark:bg-white/10 dark:text-purple-200 dark:hover:bg-white/20"
diff --git a/src/client/index.ts b/src/client/index.ts
index 5bb6bbc..f63162d 100644
--- a/src/client/index.ts
+++ b/src/client/index.ts
@@ -2,13 +2,11 @@ import "./polyfill";
 import {
   ApiFromModules,
   FunctionReference,
-  GenericActionCtx,
   GenericDataModel,
   type HttpRouter,
-  WithoutSystemFields,
   actionGeneric,
-  createFunctionHandle,
   httpActionGeneric,
+  GenericActionCtx,
 } from "convex/server";
 import {
   type ComponentApi,
@@ -18,17 +16,18 @@ import {
   RunQueryCtx,
 } from "../component/util";
 import { Polar as PolarSdk } from "@polar-sh/sdk";
-import { Doc } from "../component/_generated/dataModel";
 import { Infer, v } from "convex/values";
 import schema from "../component/schema";
 import { WebhookSubscriptionCreatedPayload } from "@polar-sh/sdk/models/components/webhooksubscriptioncreatedpayload.js";
 import { WebhookSubscriptionUpdatedPayload } from "@polar-sh/sdk/models/components/webhooksubscriptionupdatedpayload.js";
 import { WebhookProductCreatedPayload } from "@polar-sh/sdk/models/components/webhookproductcreatedpayload.js";
 import { WebhookProductUpdatedPayload } from "@polar-sh/sdk/models/components/webhookproductupdatedpayload.js";
+import { Checkout } from "@polar-sh/sdk/models/components/checkout.js";
 import {
   validateEvent,
   WebhookVerificationError,
 } from "@polar-sh/sdk/webhooks";
+import { EmptyObject } from "convex-helpers";
 
 export const subscriptionValidator = schema.tables.subscriptions.validator;
 export type Subscription = Infer<typeof subscriptionValidator>;
@@ -45,14 +44,14 @@ export type CheckoutApi<DataModel extends GenericDataModel> = ApiFromModules<{
 
 export class Polar<DataModel extends GenericDataModel> {
   private polar: PolarSdk;
-  public onScheduleCreated?: SubscriptionHandler;
   constructor(
     public component: ComponentApi,
-    options: {
-      onScheduleCreated?: FunctionReference<
-        "mutation",
+    private options: {
+      getUserInfo?: FunctionReference<
+        "query",
         "internal",
-        { subscription: WithoutSystemFields<Doc<"subscriptions">> }
+        EmptyObject,
+        { userId: string; email?: string }
       >;
     } = {}
   ) {
@@ -61,41 +60,48 @@ export class Polar<DataModel extends GenericDataModel> {
       server:
         (process.env["POLAR_SERVER"] as "sandbox" | "production") ?? "sandbox",
     });
-    this.onScheduleCreated = options.onScheduleCreated;
   }
   getCustomerByUserId(ctx: RunQueryCtx, userId: string) {
     return ctx.runQuery(this.component.lib.getCustomerByUserId, { userId });
   }
-  /*
   async createCheckoutSession(
     ctx: GenericActionCtx<DataModel>,
     {
       productId,
       userId,
       email,
-    }: { productId: string; userId: string; email: string }
-  ) {
-    const customer =
-      (await ctx.runQuery(this.component.lib.getCustomerByUserId, {
+      origin,
+    }: { productId: string; userId: string; email: string; origin: string }
+  ): Promise<Checkout> {
+    const dbCustomer = await ctx.runQuery(
+      this.component.lib.getCustomerByUserId,
+      {
         userId,
-      })) ||
-      (await this.polar.customers.create({
-        email,
-        metadata: {
-          userId,
-        },
-      }));
-    const customerId = customer?.id;
-    if (!customerId) {
-      throw new Error("Customer not found");
+      }
+    );
+    const customerId =
+      dbCustomer?.id ||
+      (
+        await this.polar.customers.create({
+          email,
+          metadata: {
+            userId,
+          },
+        })
+      ).id;
+    if (!dbCustomer) {
+      await ctx.runMutation(this.component.lib.insertCustomer, {
+        id: customerId,
+        userId,
+      });
     }
-    return this.polar.checkouts.custom.create({
+    return this.polar.checkouts.create({
       allowDiscountCodes: true,
-      productId,
+      products: [productId],
       customerId,
+      embedOrigin: origin,
     });
   }
-    */
   listProducts(
     ctx: RunQueryCtx,
     { includeArchived }: { includeArchived: boolean }
@@ -117,15 +123,16 @@ export class Polar<DataModel extends GenericDataModel> {
     return ctx.runQuery(this.component.lib.getProduct, { id: productId });
   }
   checkoutApi(opts: {
+    products: Record<string, string>;
     getUserInfo: (ctx: RunQueryCtx) => Promise<{
       userId: string;
-      email?: string;
+      email: string;
     }>;
   }) {
     return {
       generateCheckoutLink: actionGeneric({
         args: {
-          productId: v.string(),
+          productKey: v.string(),
           origin: v.string(),
         },
         returns: v.object({
@@ -133,17 +140,13 @@ export class Polar<DataModel extends GenericDataModel> {
         }),
         handler: async (ctx, args) => {
           const { userId, email } = await opts.getUserInfo(ctx);
-          const { url } = await this.polar.checkouts.create({
-            productId: args.productId,
-            embedOrigin: args.origin,
-            customerEmail: email,
-            metadata: {
-              userId,
-            },
+          const { url } = await this.createCheckoutSession(ctx, {
+            productId: opts.products?.[args.productKey],
+            userId,
+            email,
+            origin: args.origin,
           });
-          return {
-            url,
-          };
+          return { url };
         },
       }),
     };
@@ -194,9 +197,6 @@ export class Polar<DataModel extends GenericDataModel> {
                   event.data.metadata.userId as string,
                   event.data
                 ),
-                callback:
-                  this.onScheduleCreated &&
-                  (await createFunctionHandle(this.onScheduleCreated)),
               });
               break;
             }
diff --git a/src/component/_generated/api.d.ts b/src/component/_generated/api.d.ts
index 84e46b3..e412c6e 100644
--- a/src/component/_generated/api.d.ts
+++ b/src/component/_generated/api.d.ts
@@ -82,7 +82,6 @@ export type Mounts = {
       "mutation",
       "public",
       {
-        callback?: string;
         subscription: {
           amount: number | null;
           cancelAtPeriodEnd: boolean;
@@ -185,6 +184,12 @@ export type Mounts = {
         userId: string;
       } | null
     >;
+    insertCustomer: FunctionReference<
+      "mutation",
+      "public",
+      { id: string; userId: string },
+      string
+    >;
     listProducts: FunctionReference<
       "query",
       "public",
diff --git a/src/component/lib.ts b/src/component/lib.ts
index fe28c9d..faf1480 100644
--- a/src/component/lib.ts
+++ b/src/component/lib.ts
@@ -1,9 +1,7 @@
-import { v, VString } from "convex/values";
+import { v } from "convex/values";
 import { mutation, query } from "./_generated/server";
 import schema from "./schema";
 import { asyncMap } from "convex-helpers";
-import { FunctionHandle, WithoutSystemFields } from "convex/server";
-import { Doc } from "./_generated/dataModel";
 
 export const getCustomerByUserId = query({
   args: {
@@ -25,6 +23,20 @@ export const getCustomerByUserId = query({
   },
 });
 
+export const insertCustomer = mutation({
+  args: {
+    id: v.string(),
+    userId: v.string(),
+  },
+  returns: v.id("customers"),
+  handler: async (ctx, args) => {
+    return ctx.db.insert("customers", {
+      id: args.id,
+      userId: args.userId,
+    });
+  },
+});
+
 export const upsertCustomer = mutation({
   args: {
     userId: v.string(),
@@ -163,21 +175,12 @@ export const listProducts = query({
   },
 });
 
-type Subscription = WithoutSystemFields<Doc<"subscriptions">>;
-const subscriptionCallbackValidator = v.string() as VString<
-  FunctionHandle<"mutation", { subscription: Subscription }>
->;
-
 export const createSubscription = mutation({
   args: {
     subscription: schema.tables.subscriptions.validator,
-    callback: v.optional(subscriptionCallbackValidator),
   },
   handler: async (ctx, args) => {
     await ctx.db.insert("subscriptions", args.subscription);
-    if (args.callback) {
-      await ctx.runMutation(args.callback, { subscription: args.subscription });
-    }
   },
 });
 
diff --git a/src/react/index.tsx b/src/react/index.tsx
index 8739c0e..f34628f 100644
--- a/src/react/index.tsx
+++ b/src/react/index.tsx
@@ -6,12 +6,12 @@ import { useAction } from "convex/react";
 
 export const CheckoutLink = <DataModel extends GenericDataModel>({
   polarApi,
-  productId,
+  productKey,
   children,
   className,
 }: PropsWithChildren<{
   polarApi: CheckoutApi<DataModel>;
-  productId: string;
+  productKey: string;
   className?: string;
 }>) => {
   const generateCheckoutLink = useAction(polarApi.generateCheckoutLink);
@@ -20,7 +20,7 @@ export const CheckoutLink = <DataModel extends GenericDataModel>({
   useEffect(() => {
     PolarEmbedCheckout.init();
     void generateCheckoutLink({
-      productId,
+      productKey,
       origin: window.location.origin,
     }).then(({ url }) => setCheckoutLink(url));
   }, []);
@@ -30,7 +30,7 @@ export const CheckoutLink = <DataModel extends GenericDataModel>({
       className={className}
       href={checkoutLink}
       data-polar-checkout
-      //data-polar-checkout-theme="light"
+      data-polar-checkout-theme="dark"
     >
       {children}
     </a>