Buy a ticket

1. The host adds products: ticket products, which issue a ticket type, and add-ons bought on top of a ticket, such as a workshop seat. Each has a quantity or none, a sales window or none, and prices with windows, so early bird can end and regular begin. Promo codes give a percent or fixed discount, with limits and a window.
2. A buyer opens Get tickets on the event page, picks tickets and add-ons, enters a code, and sees the total from the server. A sold-out or closed ticket shows but cannot be added; an add-on that is not on sale is not offered.
3. The buyer signs in to pay; the cart waits. On a host's own site, selling through the public API, the buyer proves their email with a code instead.
4. Paying holds the units for about half an hour while Stripe Checkout takes the card. A zero-total order completes at once and needs no Stripe account.
5. When Stripe confirms, the tickets and add-ons are issued to the buyer, unclaimed, and the receipt goes out. Stripe's own receipt and invoice are kept as links on the order.
6. The buyer finds the tickets under Tickets and the order under Orders in the app.

Rules: nothing can be ordered once the event has ended. An unpaid hold expires and its units return to sale. Every price in an event is in one currency, and a price is never edited, only ended and replaced. A hidden product sells by a link, /events/<slug>/checkout?product=<id>. An add-on is bought inside a ticket in the same order. Anything an order has touched can be hidden or ended, not deleted.