Adding Stripe Payments to Your AI-Built App

Stripe handles the complexity of payment processing — credit cards, subscriptions, invoices, tax, and compliance. You integrate it through their API. The flow: your app creates a checkout session, Stripe hosts the payment page, the user pays, and Stripe notifies your app via webhooks. You never handle credit card numbers directly.

For single purchases: create a Stripe Checkout session with the product details and redirect the user to Stripe's hosted payment page. After payment, Stripe redirects back to your success page. Use webhooks to confirm the payment and update your database — don't rely on the redirect alone, as users might close the tab.

For recurring payments: create Products and Prices in Stripe (e.g., $19/month). Use Checkout to start the subscription. The critical piece is webhook handling — you need to listen for subscription.created, invoice.paid, invoice.payment_failed, and customer.subscription.deleted events to keep your database in sync with Stripe.

Webhooks are how Stripe tells your app about events (payments, refunds, subscription changes). Create an API endpoint that receives POST requests from Stripe, verifies the signature (to prevent spoofing), and processes the event. This endpoint must be publicly accessible — it won't work on localhost without a tunnel.

Stripe provides a hosted customer portal where users can update their payment method, switch plans, cancel subscriptions, and download invoices. It takes about 5 minutes to set up and saves you from building all of this yourself. Configure it in the Stripe Dashboard and link to it from your app.

Not verifying webhook signatures (security risk). Relying on the checkout success redirect instead of webhooks (unreliable). Using test keys in production. Not handling failed payments and subscription lapses. Hardcoding prices instead of using Stripe Price IDs. Not setting up the customer portal.