Lookups

Payment lookups

Lookup pages for when a payment is failing and you need the exact answer: what a code means, which test value triggers a scenario, why a verification or signature check fails, what to do next. Not Flint documentation; these cover the payments ecosystem, with a short bridge to how each topic works on Flint.

Card decline codes
Every decline code that matters: what the issuer is saying, whether a retry can work, what to tell the customer, and the network retry rules that make blind retries expensive.
Test card numbers
Every documented test card and failure trigger for Stripe, Square, Adyen, Braintree, PayPal, and Authorize.net, plus the nine cards that matter in every Flint sandbox.
Apple Pay domain verification failed
Every way the well-known file fetch fails: redirects, bot protection, TLS trust, stale files, and the Stripe Connect account trap, with a five minute curl diagnosis.
Stripe webhook signature errors
"No signatures found matching the expected signature for payload" means one of three things: a parsed body, the wrong whsec_ secret, or a mangled header. Fixes per framework.
How to refund a line item in Stripe
Stripe refunds are amount-only. The two real paths: credit notes when an invoice exists, per-unit proration everywhere else, plus the discount, tax, and rounding traps and the metadata that keeps accounting reconciled.
How to add a tip to an online Stripe checkout
Stripe tipping runs on Terminal readers only, and "customers choose what to pay" replaces your price. Four online workarounds with code, the coupon, tax, and refund traps, and a hosted checkout with a tip prompt.
Stripe inventory management: how to prevent overselling
Stripe has no stock counts, and a Checkout session can stay open for 24 hours. How to hold stock, make a Payment Link say sold out, the five race windows that oversell during spikes, and a payments API that checks stock before it charges.
Does Stripe have an Orders API?
No. Two Orders APIs shipped and both were retired: v1 in October 2019 over SCA, the 2022 beta removed before GA. What ranks under the name now, what replaced the order object, and where the order layer lives today.
Stripe as your source of truth
For payment state, yes, and only from webhooks. For the sale, it can't be: Stripe's own fulfillment guide keeps orders in your database. The domain split, the read-allocation math, and the five drift traps.
Which Stripe webhook event should you trust?
checkout.session.completed or payment_intent.succeeded? The event to fulfill from for each integration, why delivery order is not guaranteed, and the one key that stops a double fulfillment.
Stripe Checkout subscription shipping: charge and ship every renewal
Checkout shipping options are payment-mode only. Shipping as a recurring price or a per-renewal invoice item, taxing it, shipping from invoice.paid, skips, moves, rate changes, and six traps.
How to offer local pickup and dynamic shipping in Stripe Checkout
Stripe Checkout has no pickup option, and a free Pickup rate still collects and taxes the buyer's address. Three workarounds with code, where address-based rates work, the five traps, and pickup as a checkout delivery method.
Why the Stripe customer portal doesn't show one-time payments
The portal lists invoices, and one-time Checkout payments have none by default. Post-payment invoices and their fee, one Customer per buyer, an order history built from Checkout Sessions, and a buyer account that lists orders on Flint.
Stripe redirectToCheckout removed: how to fix it
Which Stripe.js versions throw, the four error messages, the session.url redirect, and Payment Links when there is no backend.
Payfac-as-a-service, compared
Finix, Worldpay (Payrix), Rainforest, Tilled, Stax Connect, Payabli, and Stripe Connect on onboarding, registration, economics, API surface, and go-live claims. Vendor-sourced, dated, conflict stated.
Webflow subscriptions after User Accounts
Webflow set January 29, 2026 to switch off User Accounts, which its native subscriptions need. What keeps charging, how subscribers manage it, and how to sell a subscription box from a Webflow button.

Looking for Flint's own documentation? Start at the docs, the API reference, or the Flint error catalog.

Card decline codes

Test card numbers

Apple Pay domain verification failed

Stripe webhook signature errors

How to refund a line item in Stripe

How to add a tip to an online Stripe checkout

Stripe inventory management: how to prevent overselling

Does Stripe have an Orders API?

Stripe as your source of truth

Which Stripe webhook event should you trust?

Stripe Checkout subscription shipping: charge and ship every renewal

How to offer local pickup and dynamic shipping in Stripe Checkout

Why the Stripe customer portal doesn't show one-time payments

Stripe redirectToCheckout removed: how to fix it

Payfac-as-a-service, compared

Webflow subscriptions after User Accounts