How to prevent creating duplicate subscription in stripe when trial period is set on subscription - stripe-payments

Question

I am encoutering a problem with stripe. let me explain my working
scenario.my requirement is do not charge user for 14 days with card up front
1)user enter card details
2)sca popup appear
3)regardless of user complete the authentication or not a subscription is created in stripe because i set trial_end_date=>now()+14 days
4)user payment fails in some reason and attempt again, another subscription created
i am worried about the duplicate subscription as the stripe will attempt to pay after the 14 days for both of these subscription as it send a Stripe-hosted link for cardholders for both of these subscription
let me give a snapshot of what i have so far
$data['customer']='customerId';
$data['items']=[];
$data['items'][0]['plan']='stripe_plan_id'
$data['default_payment_method']='pm_xxxx'
$data['trial_end']= strtotime('+14 days');
$data['prorate']=true;
$data['tax_percent']=env('VAT_PERCENTAGE');
$data['expand']= ['latest_invoice.payment_intent', 'pending_setup_intent'];
try {
$subscription=\Stripe\Subscription::create($data);
}
catch(Exception $e) {
return response()->json(['success' => false,'message'=>$e->getMessage()]);
}
what i am missing? how to prevent the duplicate subscription scenario.please expain with the correct example which is i am missing.thanks in advance

Answer 1

I think the problem is in your payment flow, there is not a stripe api that explicitly detects duplicate subscription. You are after all allowed to assign more then 1 subscription per customer id. You can create idempotent keys, but that isn't for the same thing you're talking about, idempotent keys are for accidently hitting the submit button twice within the same timeframe.
The solution would be to attach a payment method to your stripe customer id before your subscription trial is over. For example if you are using stripe elements you would call
Node/JS Example below :
const result = await stripe.createPaymentMethod({
type: 'card',
card: card
})
then pass that result to your backend
const result = await stripe.paymentMethods.attach(paymentMethodId, {customerId})
You do not need to create a new subscription, as one has already been created for that user. Credit cards are assigned to customer Ids, and not to subscriptions. Stripe will do the rest.
You do also need to update the customer with the default payment method as follows :
const customer_update = await stripe.customers.update(stripeCustomerId,{invoice_settings: {default_payment_method:paymentMethodId}});
Now when you visit your dashboard you will see a default card assigned to your customer. Once the subscriptions falls out of the trail period, the default card will be charged.
So in this case there wont be a duplicate subscription created, as you are not calling stripe.subscriptions.create again.