# Agent payments create

`POST /agent-payments` · Skerry · Agents paying

Send the agent's request to a merchant and, when it answers 402, pay one offer and send the request once more. Returns the merchant's status, an excerpt of its body and what was paid. `max_amount` is a ceiling in US cents; the merchant's exact amount is what is paid. Under the agent's mandates and the customer's controls: it may be refused, or held for approval (202). Pays at most once per key. Needs an Idempotency-Key.

- Scope: agent-payments:write
- Moves money: yes
- Idempotency: required
- Untrusted: response.body, reason, merchant.url, external_ref

## Parameters

- `Idempotency-Key` (header, required), string: A repeat with the same key and body returns the first answer instead of acting twice.

## Request body

`application/json`

```json
{
  "type": "object",
  "required": [
    "agent_id",
    "url",
    "max_amount",
    "currency"
  ],
  "properties": {
    "agent_id": {
      "type": "string",
      "maxLength": 100,
      "description": "The registered agent that pays."
    },
    "wallet_id": {
      "type": "string",
      "maxLength": 100,
      "description": "The agent's wallet to sign from. Left out, its newest active wallet is used."
    },
    "url": {
      "type": "string",
      "format": "uri",
      "maxLength": 2000,
      "description": "The merchant's address: public, https, a host name."
    },
    "method": {
      "type": "string",
      "enum": [
        "GET",
        "POST",
        "PUT",
        "PATCH",
        "DELETE"
      ]
    },
    "headers": {
      "type": "object",
      "maxProperties": 20,
      "additionalProperties": {
        "type": "string",
        "maxLength": 2000
      },
      "description": "Headers sent to the merchant. The ones a payment is carried in may not be set."
    },
    "body": {
      "oneOf": [
        {
          "type": "string"
        },
        {
          "type": "object"
        }
      ],
      "description": "Sent to the merchant as it is; an object is sent as JSON. Up to 64 KB."
    },
    "max_amount": {
      "type": "integer",
      "minimum": 1,
      "description": "The most that may be paid, in US cents. What is paid is the merchant's exact amount."
    },
    "currency": {
      "type": "string",
      "enum": [
        "usd"
      ]
    },
    "payment_method_id": {
      "type": "string",
      "maxLength": 200,
      "description": "A saved payment method a delegated payment token is issued on, for a merchant that takes one."
    },
    "external_ref": {
      "type": "string",
      "maxLength": 200,
      "description": "The document this belongs to in your own system."
    },
    "external_kind": {
      "type": "string",
      "enum": [
        "invoice",
        "bill",
        "order",
        "booking",
        "other"
      ]
    },
    "dry_run": {
      "type": "boolean",
      "description": "Check the request and report what would happen, without doing it."
    }
  }
}
```

## Responses

- `200`: Success.
- `202`: requires_approval — Not an error: the operation is held for a person. The body names the approval.
- `400`: price_below_minimum — The price is below the smallest single payment for a method (`detail.method`, `detail.minimum`), or has a part of a cent. Set `credit_only`, raise the price, or drop the method.
- `401`: dpop_invalid — The token is bound to a key and the DPoP proof was missing, wrong for this request, or already used.
- `402`: payment_failed — The payer's bank or card refused. `detail.reason` says why in plain terms.
- `403`: agent_payment_over_max — The merchant asks for more than `max_amount`. Nothing was signed. `detail.asked_minor` is the lowest price asked, in US cents.
- `404`: not_found — No such object in this project — including one that belongs to somebody else.
- `409`: token_not_issued — A delegated payment token could not be issued ready to use, for instance because the payer would have to act. Nothing was sent to the merchant.
- `429`: too_many_waiters — This key already has as many requests waiting (`?wait=`) as it may. Let one finish, or read without wait.
- `500`: internal_error — Ours. Quote the `request_id` and we can find the call.
- `502`: platform_error — A provider failed. Safe to retry with the same Idempotency-Key.
- `503`: oauth_unavailable — The authorisation server's keys could not be read, so tokens cannot be checked. API keys still work.

## Example

```sh
curl -X POST 'https://api.skerry.xyz/agent-payments' \
  -H 'Authorization: Bearer $KEY' \
  -H 'Content-Type: application/json' \
  -d '"{ agent_id, wallet_id?, url, method?, headers?, body?, max_amount, currency: usd, payment_method_id?, external_ref?, external_kind? }"'
```