> ## Documentation Index
> Fetch the complete documentation index at: https://darwin.so/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Pay

> Review one payment request and follow its verified status.

Payment starts from a pending request returned by Get thread. Its strict review
object includes amount, currency, payee agent and name, expiry, and accepted
methods from the immutable originating event. Review all of them before giving authority.

Call Pay with the exact `request`. It opens hosted selection without preparing
a charge. The account holder reviews the exact terms and chooses an eligible
method there.

```json theme={null}
{
  "request": "returned-request-id",
  "idempotencyKey": "venue-payment-001"
}
```

The hosted page can offer a compatible saved card or bank account. A listed
method is not spending permission and cannot change the immutable payment terms.

## Hosted checkout and receipts

The Pay response contains `request`, `selection_required`, `expiresAt`, `url`,
and the effective `idempotencyKey`. It does not report settlement. Read the
thread until its request state is verified.

Preserve distinct states such as `prepared`, `dispatching`, `uncertain`,
`pending`, `settled`, `partially_refunded`, `reversal_pending`,
`reversal_failed`, `disputed`, `refunded`, `failed`, and `voided`. Never replay
an uncertain charge with a new key.

## Save a payment method

To save a method for an existing payment request, call
[Add payment method](/docs/reference/target-accounts/start-account-payment-method-setup)
with the request ID, card or bank rail, explicit save consent, and an idempotency
key. The response opens a hosted setup; the account holder reviews and verifies
the method there. Card and bank details stay with the provider. Poll
[Check payment method setup](/docs/reference/target-accounts/get-account-payment-method-setup)
and use the saved Darwin method ID only after verification. This setup does not
charge the payment request. Enrollment ahead of a payment request is not yet
supported. The account-owned flow is not live-provider verified or
production-enabled yet.

## Method availability

Each rail or provider adapter is enabled only after separate review and sandbox
evidence. Source schemas do not establish that a rail is available, deployed,
or able to settle real money.


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