Billing Architecture: Stripe

Stripe is the 'OS' for internet commerce. For an architect, the key is not just 'Accepting Cards', but building a **Scalable Billing Pipeline**.

1. Stripe Checkout vs Elements

Use **Stripe Checkout** for your MVP. It's a pre-built page hosted by Stripe that handles the payment, address collection, and validation. It's the fastest way to launch and you don't have to worry about PCI compliance.

2. The Webhook Listener

The DB update shouldn't happen when the 'Pay' button is clicked. It should happen when Stripe sends a **Webhook (`checkout.session.completed`)**. This ensures your data is only updated AFTER the money is confirmed. **Security Tip:** Always verify the Stripe Signature on your webhook endpoint to prevent attackers from 'Faking' a success event.

3. Tax and VAT

Selling globally means you are liable for taxes in 100+ countries. Use **Stripe Tax**. It automatically calculates and collects the correct VAT/GST based on the user's location. Don't try to code this yourself—the legal risk is massive.

4. Career Mastery

Q: "How do I handle 'Dunning' (Failed payments)?"

Architect Answer: "Enable **Stripe Smart Retries**. Stripe will automatically retry the card at the optimal time (e.g., payday) and send 'Update your card' emails for you. Automated dunning can recover 10-15% of your MRR without you lifting a finger."