Paddle Subscription or Product Web Purchase

<div class="section">
  PADDLE TEST
  <a href="#!" id="buy">Buy now!</a>
  <script type="text/javascript">
    function openCheckout() {
      Paddle.Checkout.open({
        product: 16491,
        passthrough: '{"custom_id":  "my_custom_userid"}',
      });
    }
    document
      .getElementById("buy")
      .addEventListener("click", openCheckout, false);
  </script>
</div>
<script src="https://cdn.paddle.com/paddle/paddle.js"></script>
<script type="text/javascript">
  Paddle.Environment.set('sandbox'); // only do this on sandbox testing.
  Paddle.Setup({ vendor: 3264 });
</script>

Glassfy.connectCustomSubscriber("my_custom_userid") { error in
    // handle error.
}

[Glassfy connectCustomSubscriber:@"my_custom_userid" withCompletion:nil];

await Glassfy.connectCustomSubscriber("my_custom_userid");