Guide 08 · Developer docs

A Core dna store is a set of records and an API that moves a purchase from cart to order: products described in every language and priced in every currency the store sells in, a cart, a checkout that becomes an order, invoices, payments, tax and shipping. The site builds the storefront on top: the cart and checkout pages, their scripts, and the customer emails.

L2–L3

Unit 03 of 08 6 pages

Building the checkout

Updated 23/10/2026 01:46

For developers building a checkout page: the checkout record and when it can be paid, how to structure the page's script, and each step a shopper takes on it, from addresses to the captcha at purchase.

Start with the checkout record: how it is created from the cart, which currency it is in and which language its lines show, the stages it passes through on the way to an order, and the four conditions that make it ready for payment, which answer "why is the pay button disabled". Then the architecture of the page itself: state seeded from the server, one API layer, a component per concern, and keeping what the shopper typed through a reload.

The pages after that follow the shopper down the page: the email, addresses and shipping rates; discount codes and automatic discounts; order metadata fields, gift options and donations; and last, guest or account checkout and the captcha that protects the purchase call. Taking the payment itself is the next unit.

In this unit

Read in order

01 The checkout and when it can be paid A checkout is the record between the cart and the order. This page follows it from creation to payment, lists the four conditions that make it ready for payment, and gives the warnings that say which one is missing. 02 The single-page checkout A checkout page is a small application. Seed its state from the server, send every call through one API module, give each concern its own component, and save what the shopper has typed so that a reload loses nothing. 03 Addresses and shipping at checkout Write the shopper's email and addresses to the checkout, add a places autocomplete without taking manual entry away, then create shipping, show its rates, and handle an address that no shipping method covers. 04 Discounts at checkout Automatic discounts and discount codes both land in the checkout's applied discounts and its discount total. How a code is added and removed, how to tell the shopper whether it helped, and what the checkout answers when it refuses one. 05 Donations, metadata and gift options The three most requested checkout additions, each with a working example: order metadata fields for extra answers, gift options built from metadata fields, and a donation added as a product in the cart. 06 Guest checkout and the captcha Guests check out with an email and no login; members check out as themselves. What each path creates, how to offer an account after purchase, and the reCAPTCHA check that stops card testing at the purchase call.