# storefront knowledge baseHow the storefront works and why it is built this way. Start with the concept notes, then read the decisions for the reasoning behind them. The architecture tab has the map of Workers and storage these notes refer to.## Concepts- [[catalog]]: products, prices and stock, and how the merchant edits them.- [[carts]]: what a cart holds and the limits it enforces.- [[product-images]]: how images get into R2 and back out.- [[checkout]]: how a cart becomes an order, and how stock and payment are handled.- [[payment-webhook]]: how Stripe's events mark orders paid or cancelled.## Decisions- [[0001-d1-for-shop-data]]: one D1 database for everything the shop sells.- [[0002-serve-images-through-the-api]]: images are served by storefront-api.- [[0003-money-in-whole-cents]]: prices and totals are integers.- [[0004-take-stock-at-checkout]]: carts check stock, checkout takes it.- [[0005-stripe-payment-intents]]: payments are Stripe PaymentIntents.- [[0006-one-writer-for-the-database]]: other Workers change orders through OrdersService.## Guides- [[testing]]: how the tests run the real SQL without workerd.