Checkout & Portal

Checkout

The pricing page posts a plain form — no JavaScript required:

<form method="POST" action="/api/stripe/checkout">
	<input type="hidden" name="plan" value="pro" />
	<button type="submit">Subscribe to Pro</button>
</form>

The endpoint (src/routes/api/stripe/checkout/+server.ts) then:

1. Validates the plan against plans.ts (free plans never reach Stripe)
2. Requires a session — anonymous users redirect to /auth/register?next=/pricing
3. Resolves the Stripe customer: reuses the stored stripe_customer_id, or creates one with the user’s email + user_id metadata
4. Creates a subscription-mode Checkout Session with client_reference_id = user.id and plan metadata on both session and subscription, so the webhook can attribute it later
5. Redirects (303) to session.url — Stripe’s hosted payment page

Success returns to /app/dashboard/billing?checkout=success; cancel returns to /pricing?checkout=cancelled.

Price resolution

For each plan the endpoint checks getPriceIdForPlan(plan.id):

• Set (STRIPE_PRICE_PRO) → uses that existing Stripe Price
• Unset → builds inline price_data from plans.ts amounts, creating the price on the fly. This is why the template works before you create anything in the Stripe dashboard.

Customer portal

The billing page’s Manage Billing in Stripe button POSTs to /api/stripe/portal, which:

1. Requires a session (redirects to login with next otherwise)
2. Resolves or lazily creates the customer (same lookup as checkout)
3. Creates a Customer Portal Session with return_url = {origin}/app/dashboard/billing

Users can update cards, download invoices, switch plans, and cancel there. One-time setup: activate the portal in Stripe → Settings → Billing → Customer portal.

After checkout

On return, the billing page reads its subscription row and shows a success banner with a refresh action. The authoritative state arrives asynchronously when Stripe delivers checkout.session.completed — see Webhooks.