import stripe
stripe.api_key = "sk_test_..."

session = stripe.checkout.Session.create(
    payment_method_types=['card'],
    line_items=[{
        'price_data': {
            'currency': 'usd',
            'product_data': {'name': 'Premium Plan'},
            'unit_amount': 2000,  # $20.00 in cents
            'recurring': {'interval': 'month'},
        },
        'quantity': 1,
    }],
    mode='subscription',
    success_url='https://example.com/success?session_id={CHECKOUT_SESSION_ID}',
    cancel_url='https://example.com/cancel',
)
# Redirect to session.url

# Backend: Create payment intent
def create_payment_intent(amount, customer_id=None):
    intent = stripe.PaymentIntent.create(
        amount=amount,  # In cents
        currency='usd',
        customer=customer_id,
        automatic_payment_methods={'enabled': True},
    )
    return intent.client_secret

// Frontend: Confirm payment
const stripe = Stripe('pk_test_...');
const {error, paymentIntent} = await stripe.confirmCardPayment(
    clientSecret,
    {payment_method: {card: cardElement}}
);

@app.route('/webhook', methods=['POST'])
def webhook():
    payload = request.data
    sig = request.headers.get('Stripe-Signature')

    try:
        event = stripe.Webhook.construct_event(
            payload, sig, 'whsec_...'
        )
    except stripe.error.SignatureVerificationError:
        return 'Invalid signature', 400

    if event['type'] == 'payment_intent.succeeded':
        handle_payment_success(event['data']['object'])
    elif event['type'] == 'customer.subscription.deleted':
        handle_subscription_canceled(event['data']['object'])

    return 'OK', 200

# Create subscription
subscription = stripe.Subscription.create(
    customer=customer_id,
    items=[{'price': 'price_xxx'}],
    payment_behavior='default_incomplete',
    expand=['latest_invoice.payment_intent'],
)

# Customer portal for self-service
session = stripe.billing_portal.Session.create(
    customer=customer_id,
    return_url='https://example.com/account',
)
# Redirect to session.url

# Full refund
stripe.Refund.create(payment_intent='pi_xxx')

# Partial refund
stripe.Refund.create(
    payment_intent='pi_xxx',
    amount=500,  # $5.00
    reason='requested_by_customer'
)