Client API

Create checkouts, open the billing portal, and manage Creem subscriptions through Better Auth.

The client plugin exposes billing methods under authClient.creem. Requests include the current Better Auth session when one is available. Portal, subscription, transaction, and access endpoints require a signed-in user; checkout can also be created without a session.

import { creemClient } from "@creem_io/better-auth/client";
import { createAuthClient } from "better-auth/react";

export const authClient = createAuthClient({
  plugins: [creemClient()],
});

The plugin infers endpoint inputs, successful responses, and Creem session fields through Better Auth. The createCreemAuthClient wrapper remains exported for compatibility but is deprecated.

Every method returns the Better Auth { data, error } result shape. Handle error before using data. A failed request returns data: null and an error containing message, status, and statusText; successful response types do not contain an error alternative.

const { data, error } = await authClient.creem.createPortal();

if (error) {
  console.error(error.status, error.message);
} else if (data.url) {
  window.location.assign(data.url);
}

Creem session fields are inferred when persistence is enabled. If the server uses persistSubscriptions: false, configure creemClient({ persistSubscriptions: false }) too. The client option controls inference; it does not change the server configuration.

Create a checkout

Navigation is manual by default (redirect: false). Set redirect: true to let Better Auth redirect to the checkout URL automatically.

const { data, error } = await authClient.creem.createCheckout({
  productId: "prod_...",
  units: 1,
  successUrl: "/billing/success",
  discountCode: "LAUNCH20",
  metadata: { plan: "pro" },
});

if (!error && data?.url) {
  window.location.assign(data.url);
}

Input	Required	Description
productId	Yes	Product to purchase.
requestId	No	Idempotency key for retrying checkout creation.
units	No	Positive unit count; defaults to 1.
discountCode	No	Active Creem discount code.
customer.email	No	Defaults to the signed-in user’s email.
customFields	No	Up to three text or checkbox fields shown during checkout.
successUrl	No	Overrides defaultSuccessUrl for this checkout.
redirect	No	Redirect automatically when true; defaults to false.
metadata	No	Application metadata. The signed-in user ID is added as referenceId.

customField is a deprecated alias for customFields. New code should use customFields.

Open the customer portal

const { data, error } = await authClient.creem.createPortal();

if (!error && data?.url) {
  window.location.assign(data.url);
}

To redirect automatically, use await authClient.creem.createPortal({ redirect: true }). The default is redirect: false, which returns the URL for manual navigation.

With persistence enabled, omit customerId so the plugin uses the current user’s stored creemCustomerId. The endpoint also accepts an explicit customer ID, but it does not verify that the ID belongs to the signed-in user. Do not pass a value obtained from untrusted client input.

Check access

hasAccessGranted() reads the signed-in user’s persisted subscriptions. It grants access for active, trialing, or paid records. A scheduled_cancel, past_due, or unpaid subscription also retains access while its periodEnd is still in the future, so customers can use time they have already paid for. A canceled subscription no longer grants access.

const { data, error } = await authClient.creem.hasAccessGranted();

if (!error && data?.hasAccessGranted) {
  console.log("Access granted", data.subscription);
}

On success, data.hasAccessGranted is a boolean. A signed-out request returns an error with status 401, disabled persistence returns 400, and a failed database check returns 500. These failures return data: null, so check error before reading the access result. Do not grant access when the check fails.

Cancel a subscription

const { data, error } = await authClient.creem.cancelSubscription({
  id: "sub_...",
});

The published client type requires the subscription ID. The endpoint does not consistently verify ownership of caller-supplied IDs, so derive the ID from billing state already authorized for the signed-in user. Use the returned success and message fields to update the interface.

Retrieve a subscription

const { data, error } = await authClient.creem.retrieveSubscription({
  id: "sub_...",
});

The result includes the subscription status, customer, product, billing dates, and metadata. Customer and product values can be IDs or expanded objects; narrow their types before reading object properties. Dates returned over HTTP are serialized values, so convert them with new Date() when you need date methods instead of assuming a JavaScript Date instance. As with cancellation, do not accept the subscription ID from an untrusted caller without checking that it belongs to the signed-in account.

Search transactions

const { data, error } = await authClient.creem.searchTransactions({
  productId: "prod_...",
  pageNumber: 1,
  pageSize: 20,
});

for (const transaction of data?.items ?? []) {
  console.log(transaction.id, transaction.status, transaction.amount);
}

The response contains data.items and data.pagination; it does not expose the SDK page iterator.

Available filters are customerId, productId, orderId, pageNumber, and pageSize. When customerId is omitted, the endpoint uses the customer associated with the signed-in user. Prefer that default: an explicit customer ID is not checked against the current user.

Type exports

Client input and result types can be imported from the package root or client entry point:

import type {
  CancelSubscriptionInput,
  CreateCheckoutInput,
  CreatePortalInput,
  HasAccessGrantedResponse,
  RetrieveSubscriptionInput,
  SearchTransactionsInput,
} from "@creem_io/better-auth";