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 04 of 08 5 pages

Taking payment

Updated 23/10/2026 01:47

For developers building a checkout's payment step: the payment methods a site can offer, how a payment becomes an order, and what to do when it is pending, challenged or declined.

Start with the payment methods and how a payment runs. It sets up the four methods, the script that hands a payment to the platform and the purchase call's answers, and says which currency a payment is taken in and which language the provider's fields use. Every other page in the unit builds on it.

After it come the wallets (Apple Pay and Google Pay through Stripe), then the waiting page and the webhooks that turn a payment confirmed later, which is every Stripe payment, into an order. Then the test provider and the check that keeps it off a live site, and last the challenges, declines and retries. The unit assumes a checkout that is ready for payment, as built in the previous unit.

In this unit

Read in order

01 Payment methods and how a payment runs The four payment methods a site can offer and what each needs, then the path every payment takes: the provider's script in the browser, the purchase call, the invoice, the currency it is charged in, and each answer your page acts on. 02 Express payments Apple Pay and Google Pay on a Core dna site come from Stripe's Express Checkout Element. Where the buttons go, how the flow differs from a card payment, and the wallet set-up to finish on the Stripe side before launch. 03 The payment-processing page and webhooks A payment the provider confirms later ends on the payment-processing page you build, and becomes an order when the provider's webhook arrives. Every state of that page, and how a webhook is validated and reconciled. 04 The mock provider Mock Pay is the test provider: it reports payments as successful and moves no money, and it must never be active on a live site. Its settings, how to test with it, and the check that proves it is off before launch. 05 3-D Secure, declines and retries How a card challenge reaches your page and what to do after it, what each decline looks like and what to show the shopper, and a retry policy that lets a shopper try again without looking like card testing.