Building a Subscription Billing System

Introduction

Subscription billing is the backbone of most SaaS businesses. In this guide, we'll build a complete billing system using Stripe.

Prerequisites

Setting Up Stripe

Install the Stripe SDK

``bash
npm install stripe @stripe/stripe-js
`

Configure Environment Variables

`bash
STRIPE_SECRET_KEY=sk_test_...
STRIPE_PUBLISHABLE_KEY=pk_test_...
STRIPE_WEBHOOK_SECRET=whsec_...
`

Creating Products and Prices

Set up your pricing in the Stripe Dashboard or via API:

`typescript
const product = await stripe.products.create({
name: 'Pro Plan',
description: 'Full access to all features',
});

const price = await stripe.prices.create({
product: product.id,
unit_amount: 4900, // $49.00
currency: 'usd',
recurring: { interval: 'month' },
});
`

Implementing Checkout

Create a checkout session to handle subscriptions:

`typescript
const session = await stripe.checkout.sessions.create({
mode: 'subscription',
payment_method_types: ['card'],
line_items: [{ price: priceId, quantity: 1 }],
success_url: ${origin}/success?session_id={CHECKOUT_SESSION_ID},
cancel_url: ${origin}/pricing,
});
`

Handling Webhooks

Webhooks are crucial for keeping your database in sync:

`typescript
switch (event.type) {
case 'customer.subscription.created':
// Handle new subscription
break;
case 'customer.subscription.updated':
// Handle subscription changes
break;
case 'invoice.payment_failed':
// Handle failed payments
break;
}
``

Conclusion

A robust billing system requires careful attention to edge cases and proper webhook handling.