Checkout API

Create dynamic checkout sessions programmatically with full control over payment flow and tracking.

Checkout sessions give you programmatic control over the payment flow. Unlike static payment links, checkout sessions are generated dynamically, allowing you to:

• Pass custom tracking IDs for each payment
• Pre-fill customer information like email
• Set dynamic success URLs based on your app’s context
• Apply discount codes programmatically
• Add metadata for internal tracking

Prerequisites

Before creating checkout sessions, you’ll need:

• A Creem account with an API key (Get your key)
• At least one product created in your dashboard

Find your product ID by going to the Products tab, clicking on a product, and selecting “Copy ID” from the options menu.

Creating a Checkout Session

Choose the integration method that works best for your stack:

Next.js

The Next.js adapter provides a route handler and React component for seamless integration.

Install the package

npm

npm install @creem_io/nextjs

Create the checkout route

// app/api/checkout/route.ts
import { Checkout } from "@creem_io/nextjs";

export const GET = Checkout({
  apiKey: process.env.CREEM_API_KEY!,
  testMode: process.env.NODE_ENV !== "production",
  defaultSuccessUrl: "/success",
});

Add a checkout button

// app/page.tsx
"use client"; // Optional: CreemCheckout also works in Server Components

import { CreemCheckout } from "@creem_io/nextjs";

export function CheckoutButton() {
  return (
    <CreemCheckout
      productId="prod_YOUR_PRODUCT_ID"
      referenceId="user_123" // Optional: Track this payment in your system
    >
      <button>Buy Now</button>
    </CreemCheckout>
  );
}

The CreemCheckout component automatically handles the checkout session creation and redirects the user to the payment page.

Next.js SDK Documentation

Explore advanced features, server components, and webhook handling.

Handling Successful Payments

After a successful payment, users are redirected to your success_url with payment details as query parameters:

https://yoursite.com/success?checkout_id=ch_xxx&order_id=ord_xxx&customer_id=cust_xxx&product_id=prod_xxx

Query parameter	Description
checkout_id	The ID of the checkout session created for this payment.
order_id	The ID of the order created after successful payment.
customer_id	The customer ID, based on the email that executed the successful payment.
subscription_id	The subscription ID of the product.
product_id	The product ID that the payment is related to.
request_id	Optional. The request/reference ID you provided when creating this checkout.
signature	All previous parameters signed by creem using your API-key, verifiable by you.

For production applications, we recommend using Webhooks to handle payment events.

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Advanced Features

Metadata

Add custom metadata to track additional information with each payment. Metadata is included in webhook events and can be retrieved later.

Next.js

<CreemCheckout
  productId="prod_YOUR_PRODUCT_ID"
  referenceId="user_123"
  metadata={{
    userId: "internal_user_id",
    planType: "premium",
    source: "marketing_campaign",
  }}
>
  <button>Subscribe</button>
</CreemCheckout>

Metadata is especially useful for tracking internal IDs, campaign sources, or any custom information you need to associate with a payment.

Custom Success URL

Override the default success URL on a per-checkout basis. This is useful for directing users to specific pages after payment based on context.

Next.js

<CreemCheckout
  productId="prod_YOUR_PRODUCT_ID"
  successUrl="/account/welcome" // Overrides defaultSuccessUrl
>
  <button>Get Started</button>
</CreemCheckout>

Pre-fill Customer Email

Lock the customer email at checkout to ensure users complete payment with the email they registered with on your platform.

Next.js

<CreemCheckout
  productId="prod_YOUR_PRODUCT_ID"
  customer={{ email: "[e-mail]" }}
>
  <button>Complete Purchase</button>
</CreemCheckout>

Apply Discount Codes

Apply discount codes programmatically to pre-fill them at checkout.

Next.js

<CreemCheckout
  productId="prod_YOUR_PRODUCT_ID"
  discountCode="LAUNCH50"
>
  <button>Claim Offer</button>
</CreemCheckout>

Discount Codes

Learn how to create and manage discount codes in your dashboard.

Seat-Based Billing

Charge for multiple units or seats by specifying the units parameter. The total price will be calculated as base_price × units.

Next.js

<CreemCheckout
  productId="prod_YOUR_PRODUCT_ID"
  units={seatCount} // Charge for 5 seats
>
  <button>Add {seatCount} Seats</button>
</CreemCheckout>

Seat-Based Billing

Learn more about implementing and managing seat-based pricing models.

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Next Steps

Checkout Customization

Brand your checkout with custom colors, logos, and themes

Checkout Custom Fields

Collect additional information from customers during checkout

Subscriptions

Learn how to manage recurring billing and subscriptions

Revenue Splits

Split revenue between multiple parties automatically