Polar

npm install @paykit-sdk/polar

const checkout = await paykit.checkouts.create({
  customer: { email: 'user@example.com' },
  item_id: 'product_abc123',
  session_type: 'one_time',
  quantity: 1,
  success_url: 'https://example.com/success',
  cancel_url: 'https://example.com/cancel',
});

// Redirect the customer to checkout.payment_url

const webhook = paykit.webhooks
  .setup({ webhookSecret: process.env.POLAR_WEBHOOK_SECRET! })
  .on('payment.created', async event => {
    /* order.created */
  })
  .on('payment.succeeded', async event => {
    /* order.paid */
  })
  .on('subscription.created', async event => {
    /* subscription.created */
  })
  .on('subscription.updated', async event => {
    /* subscription.updated */
  })
  .on('subscription.canceled', async event => {
    /* subscription.revoked */
  })
  .on('customer.created', async event => {
    /* customer.created */
  })
  .on('customer.updated', async event => {
    /* customer.updated */
  })
  .on('customer.deleted', async event => {
    /* customer.deleted */
  })
  .on('invoice.generated', async event => {
    /* emitted alongside payment.succeeded on order.paid */
  })
  .on('refund.created', async event => {
    /* refund.created */
  });

await webhook.handle({
  body: rawBody,
  headersAsObject: Object.fromEntries(request.headers),
  fullUrl: request.url,
});

paykit.webhooks
  .setup({ webhookSecret: process.env.POLAR_WEBHOOK_SECRET! })
  .on('polar.order.paid', async event => {
    // event.data is typed as Polar Order
  })
  .on('polar.subscription.revoked', async event => {
    // event.data is typed as Polar Subscription
  })
  .on('polar.refund.created', async event => {
    // event.data is typed as Polar Refund
  });

// checkout.provider_metadata is spread into Polar's CheckoutCreate
await paykit.checkouts.create({
  customer: { email: 'user@example.com' },
  item_id: 'product_abc123',
  session_type: 'one_time',
  quantity: 1,
  success_url: 'https://example.com/success',
  cancel_url: 'https://example.com/cancel',
  provider_metadata: {
    allowDiscountCodes: true,
    discountId: 'discount_xyz',
  },
});

// customer.provider_metadata is spread into Polar's CustomerCreate / CustomerUpdate
await paykit.customers.create({
  email: 'user@example.com',
  provider_metadata: {
    externalId: 'usr_123',
  },
});

// updateSubscription.provider_metadata is REQUIRED and must be one of these shapes:
await paykit.subscriptions.update('sub_123', {
  provider_metadata: { productId: 'product_456' }, // change product
});
await paykit.subscriptions.update('sub_123', {
  provider_metadata: { discountId: 'discount_789' }, // apply discount
});
await paykit.subscriptions.update('sub_123', {
  provider_metadata: { trialEnd: new Date('2025-12-31') }, // extend trial
});

// refund.provider_metadata is spread into Polar's refund create
await paykit.refunds.create({
  payment_id: 'order_abc123',
  amount: 1000,
  reason: 'customer_request',
});