# arPay

mutation · in the family [Selling](/reference/selling/)

## What it does

Take a payment against a customer’s house account.

PAY DOWN a house account: ONE payment AREntry + the CONDITIONED balance decrement + THE FIFO FRONTIER ADVANCE land in ONE transaction (strictly oldest-first over open charges; ledger entries stay 100% immutable — the frontier pair moves on the MASTER). amountMinor ≤ arBalanceMinor else CONFLICT/INSUFFICIENT_AR_BALANCE naming live figures (AR never negative; prepayment/credit balances = the named deferral). NO allocations array (deterministic law + the event lake = the audit trail). Requires the unrestricted capability.

## What happens

The payment applies strictly oldest-first across open charges — the deterministic law; the ledger records it forever.

## Careful

Money in, applied oldest-first ALWAYS (no cherry-picking invoices in v1 — that is the recorded rule).

## Who may call it

Capability area: **Selling** — Ringing sales, serving customers and issuing invoices.

- Owner
- Manager
- Associate Manager
- Sales Associate
- Cashier
- An API key whose scope allows `api:arPay`

## Arguments

| Name | Type | Required | Notes |
| --- | --- | --- | --- |
| `input` | [ArPayInput](/types/ArPayInput/) `ArPayInput!` | yes | No further notes. |

## Returns

[OrgCustomer](/types/OrgCustomer/) `OrgCustomer!` — An OrgCustomer — the per-org selling ENABLEMENT of a group CorporateCustomer, the sell-side mirror of the OrgVendor: an ACTIVE OrgCustomer IS the B2B selling enablement (no B2B terms without one). Parent = the ORGANIZATION (not the family root); the selection IS the (org × corporateCustomer) edge — ≤1 live per pair via the UNIQ pair marker minted IN the create transaction. Terms payload: accountNumber · canned paymentTerms (the registry SHARED with the OrgVendor; NO free-text twin — a born construct starts canned-only) · creditLimit/orderMinimum house Money on the sell-side currency rule (NO local currency field — every money field matches the org's defaultCurrency at set, create AND edit; the OrgVendor's local purchasingCurrency is deliberately NOT mirrored; ENFORCEMENT is credit / minimums) · the customerPriceGroupId carrier (in-tenant + ACTIVE at set — the member-carrier class; the order-time B2B precedence law is; the CPG doom RI gains this SECOND carrier class) · billToContactId/shipToContactId (non-doomed + a LIVE ContactAssignment on THIS customer's host — sell-side counterparty addresses need host-membership integrity, the disclosed OrgVendor divergence). Deactivate FREE (selling paused); doom structurally unblocked EXCEPT live holder ExemptionCertificates. The priceListId carrier is LIVE. MOQ/case enforcement is.

## Example request

```graphql
mutation ExampleArPay($input: ArPayInput!) {
  arPay(input: $input) {
    id
    sysId
    type
    caption
    status
    parentId
    rootId
    createdAt
    updatedAt
    revisionNum
    revision
    corporateCustomerId
    accountNumber
    paymentTerms
    customerPriceGroupId
    priceListId
    billToContactId
    shipToContactId
    code
    arBalanceMinor
    arCurrency
  }
}
```

Variables:

```json
{
  "input": {
    "orgCustomerId": "01900000-0000-7000-8000-ba56ff800000",
    "amountMinor": 1,
    "reason": "Correcting a miscount."
  }
}
```

Send it with the envelope naming the version: `"extensions": {"at": {"version": {"name":"genesis","number":0}}}`.

## Example response

```json
{
  "data": {
    "arPay": {
      "id": "01900000-0000-7000-8000-37386ae00000",
      "sysId": "EC-EXMP-0000-000F",
      "type": "OrgCustomer",
      "caption": "Blue jeans",
      "status": "active",
      "parentId": "01900000-0000-7000-8000-065235280000",
      "rootId": "01900000-0000-7000-8000-a093dd800000",
      "createdAt": "2027-01-31T00:00:00.000Z",
      "updatedAt": "2027-01-31T00:00:00.000Z",
      "revisionNum": 1,
      "revision": "01900000-0000-7000-8000-b7960e180000",
      "corporateCustomerId": "01900000-0000-7000-8000-e09097190000",
      "accountNumber": "<account number>",
      "paymentTerms": "<payment terms>",
      "customerPriceGroupId": "01900000-0000-7000-8000-dfbf5aa40000",
      "priceListId": "01900000-0000-7000-8000-7844e9fb0000",
      "billToContactId": "01900000-0000-7000-8000-cd1d9f9e0000",
      "shipToContactId": "01900000-0000-7000-8000-abe45fdf0000",
      "code": "BJ-001",
      "arBalanceMinor": 1,
      "arCurrency": "<ar currency>"
    }
  },
  "extensions": {
    "at": {
      "callId": "01EXAMPLE-CALL-ID",
      "version": {
        "requested": {
          "name": "genesis",
          "number": 0
        },
        "serviced": {
          "name": "genesis",
          "number": 0
        }
      }
    }
  }
}
```

## Errors this call can answer

- `VALIDATION/INVALID` — Something in the request is not valid. ([VALIDATION](/errors/VALIDATION/))
- `AUTHN/REQUIRED` — Sign in to do this. ([AUTHN](/errors/AUTHN/))
- `AUTHZ/FORBIDDEN` — Your role does not allow this action. ([AUTHZ](/errors/AUTHZ/))
- `RATE_LIMIT/THROTTLED` — Too many requests in a short time. ([RATE_LIMIT](/errors/RATE_LIMIT/))
- `NOT_FOUND/*` — That record could not be found. ([NOT_FOUND](/errors/NOT_FOUND/))
- `CONFLICT/*` — The record’s state, or a change made in the meantime, does not allow this; the codes are on the CONFLICT page. ([CONFLICT](/errors/CONFLICT/))
- `VALIDATION/VERSION_REQUIRED` — The request did not say which app version it came from. ([VALIDATION](/errors/VALIDATION/))

## Used in

- [Bill a business customer and collect on account](/use-cases/bill-a-business-customer/)