Apply a single payment to multiple invoices (atomic create)

Atomic-create endpoint for multi-invoice AR cash payment application. Accepts a complete payment + applications payload in ONE transactional call. Creates one order_payments row (order_id = NULL) and N order_payment_applications rows. Validates sum(applications[].amount_applied) <= amount within $0.005. Each invoice's balance_due must cover its application. Posts one GL journal entry for the applied portion (DR Cash-equivalent / CR AR). Broadcasts payment.applied_multi_invoice + per-invoice order.payment_status_changed events. Industry standard: NetSuite Customer Payment + Auto Apply, QuickBooks Payment Line[] + unapplied credit, Acumatica AR Document Applications + Auto-Application. Idempotent via Idempotency-Key header. Auto-apply: pass auto_apply=true (and omit applications) to have the server allocate the payment oldest-first across the account open invoices (capped per invoice balance_due). The response returns the computed applications[]. Unapplied cash: if the amount exceeds what the open invoices can absorb, pass route_unapplied='credit' to hold the surplus as a credit-on-account (a balanced DR clearing / CR Customer Credits journal entry posts in the same transaction and the account credit_balance is incremented). Without route_unapplied, a surplus is REFUSED (no silent cap). Every applications[].order_id must be a RECEIVABLE, i.e. a member of the canonical AR invoice set: a document_type='invoice' row, or a sales_order invoiced in place (it carries an invoice_number with a posted, overdue or paid invoice_status). A target outside that set is refused with 422 application_target_not_receivable, which names the document's role and, where the receivable lives elsewhere, the invoices that carry it (receivable_invoices[]). In particular a PARENT sales order whose shipments were invoiced as separate child invoices is NOT a valid target: its balance_due mirrors those children, so cash applied to it would never reach them. Apply to the child invoices instead. Such a parent reports document_role='order_parent' whether or not those child invoices are still open, and receivable_invoices[] carries the OPEN ones only: a parent whose invoices are ALL settled is refused with an empty receivable_invoices[], its settled invoices named in the hint, and is told to hold the cash on the account (route_unapplied='credit'), never to take it as a deposit on the order. A sales order that has not been invoiced at all is not a target either: take that money as a deposit on the order, or hold it on the account with route_unapplied='credit'.

POST /payments/multi-invoice-apply

Apply a single payment to multiple invoices (atomic create)

cURL

curl --request POST \
  --url https://api.arcuserp.com/v1/payments/multi-invoice-apply \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "account_id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
  "amount": 5000,
  "auto_apply": true,
  "route_unapplied": "credit",
  "applications": [
    {
      "order_id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
      "amount_applied": 2500
    }
  ],
  "check_number": "<string>",
  "check_date": "2023-12-25",
  "external_reference": "<string>",
  "notes": "<string>",
  "payment_date": "2023-12-25"
}
'

200

{
  "data": {
    "id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
    "entity_id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
    "amount": 123,
    "payment_method": "<string>",
    "status": "<string>",
    "journal_entry_id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
    "applied_count": 123,
    "applications": [
      {
        "id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
        "order_id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
        "amount_applied": 123
      }
    ]
  },
  "idempotent_replay": true
}

Authorizations

Authorization · string · header · required

API key issued per entity via Settings > Developers > API Keys. Each key carries scopes (e.g. orders:read, products:write). Bearer token format: Authorization: Bearer ark_live_ent_Test keys use ark_test_ent_. Both are issued per entity
via Settings > Developers > API Keys.

Headers

Idempotency-Key · string

Client-generated unique key for idempotent POST/PATCH/DELETE operations. Alias for the Idempotency parameter. Max 255 chars. On retry with the same key, the original response is returned without re-executing the operation. Keys expire after 24 hours.

Maximum string length: 255

Body

application/json

account_id · string<uuid> · required

The customer account receiving this payment.

payment_method · enum<string> · required

Tender method for this payment.

Available options: check, ach, wire, external, cash, credit

amount · number · required

Total payment amount in dollars (cash actually received). The sum of applications[].amount_applied must be <= amount; any surplus requires route_unapplied='credit'.

Example:

5000

auto_apply · boolean

When true (and applications omitted), the server allocates the payment oldest-first across the account open invoices. The response returns the computed applications[].

Example:

true

route_unapplied · enum<string>

When 'credit', any surplus (amount beyond what open invoices absorb) is held as a credit-on-account via a balanced journal entry in the same transaction. Without it, a surplus is refused (no silent cap).

Available options: credit

applications · object[]

Per-invoice application lines (manual override). Omit when auto_apply=true. Sum of amount_applied must be <= amount; any remainder requires route_unapplied='credit'.

Required array length: 1 - 50 elements

Show child attributes

check_number · string

Check number (for check payments).

check_date · string<date>

Check date (YYYY-MM-DD).

external_reference · string

External reference (ACH trace number, wire memo, etc.).

notes · string

Internal notes for this payment.

payment_date · string<date>

Payment date for GL posting (YYYY-MM-DD; defaults to today).

Response

200

application/json

Payment applied successfully

data · object

Show child attributes

idempotent_replay · boolean