Knox
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03 BuildRather not host a payment form at all? Create a session and send your customer to Knox's page.

Checkout

A hosted payment page for your Checkout Sessions.

Create a Checkout Session with the Stripe SDK, send your customer to its url, and Knox's hosted page takes the payment. Available in test mode.

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Knox Checkout on a phone: the merchant name with a Test mode badge, the order total, an email field, and card fields for number, expiry, CVC, cardholder name, country and ZIP above a Pay button.
Knox's own Checkout page at 390 px, captured in test mode.

Checkout Sessions

Stripe-compatible sessions

Use the Checkout Sessions API you know: payment and setup modes, line items from prices or price_data, and the hosted page. Sessions expire after 24 hours unless you set expires_at between 30 minutes and 24 hours.

Terminal
curl https://api.knoxapi.com/v1/checkout/sessions -u $KNOX_SECRET_KEY: \
  -d mode=payment \
  -d "line_items[0][price]=price_..." \
  -d "line_items[0][quantity]=1" \
  --data-urlencode "success_url=https://shop.example/done?id={CHECKOUT_SESSION_ID}" \
  --data-urlencode "cancel_url=https://shop.example/cart"

Redirect contract

Your customer comes back where you expect

success_url
After payment, Knox sends the customer to your success_url, with {CHECKOUT_SESSION_ID} replaced by the session's id.
cancel_url
The back link next to your business name returns the customer to your cancel_url.
Absolute URLs
Both must be absolute http or https URLs. Knox refuses any other kind.

Behavior

Built for phones, authentication and retries

  • Responsive layout

    Two columns from 992 px wide, one column below. At 390 px and narrower the form runs full width with 16 px gutters, and fields are 44 px tall with 16 px text.

  • 3-D Secure

    Cards that need authentication go through 3-D Secure and return to the checkout page, which shows the result. 3-D Secure for setup-mode sessions is not supported yet.

  • Safe retries

    Each session has one PaymentIntent. A retry after a network error reuses the same idempotency key, and a session that is already paid completes instead of charging again.

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Paste the prompt into your coding agent, or start a test account and look around first. Live payments are available by request.

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