Accounts Payable Invoice field guide

An Accounts Payable (AP) Invoice records an approved supplier claim for goods or services. OSERP should match it to a purchase order, receipt, service confirmation, or approved non-PO policy before creating a liability. It is not a payment and should never be used to correct inventory silently.

Header fields

Open Accounting → Payable Invoices → New.

Field	Example	Purpose and impact
Invoice number	AP-2026-004281	Internal audit key
Supplier	NovaBio GmbH	Payable and statement owner
Supplier invoice no.	NB-INV-88210	Duplicate detection
Company	Demo Retail Group LLC	Legal ledger scope
Branch	DXB-MAIN	Responsibility and tax
Source type	Purchase receipt	Matching evidence
Source ID	GRN-0041	Quantity and quality trace
Invoice date	2026-10-03	Supplier document date
Posting date	2026-10-04	Accounting period
Due date	2026-11-02	Cash forecast and ageing
Currency	USD	Settlement and FX
Exchange rate	3.6725	Functional value
Payment term	Net 30	Due-date rule
Tax treatment	Import	Tax and landed cost
Status	Draft / approved / posted	Liability gate

Header also stores purchase order, contract, supplier reference, payment method, bank account, withholding class, project/WBS, cost centre, attachments, and approval route. Supplier invoice number should be unique within supplier and company scope.

Detail fields

Field	Example	Purpose and impact
Line number	10	Stable source reference
Item/service	MED-INS-100	Inventory, expense, or asset
Description	Insulin Pen 5-pack	Printed explanation
Invoiced quantity	480	Supplier claim
UoM	CARTON	Quantity interpretation
Unit price	USD 42.00	Commercial value
Discount	2%	Cost and approval
Tax code	IMPORT	Tax calculation
Receipt quantity	480	Three-way match
Batch/serial	NB240901A	Traceability
Account	131100	Inventory/expense mapping
Cost centre	DXB-COLD	Responsibility
Project/WBS	HOSP-2026	Budget and margin
Withholding	0% / 5%	Payment deduction

Show ordered, received, accepted, invoiced, credited, and open quantities. A supplier invoice for 500 cartons against a receipt of 480 should create an exception or remain unmatched according to tolerance; it must not increase stock to 500.

Three-way match

Matching compares PO price and quantity, receipt quantity and quality, and invoice amount and tax. Tolerance fields include quantity percentage, price amount, tax difference, freight, currency rounding, and owner. A variance record stores source lines, value, reason, status, and approval.

For a USD 42 price, a supplier invoice at USD 43.20 creates a USD 1.20 variance per carton. Approve only under the configured threshold or amend the PO with evidence. The invoice remains linked to the original PO and receipt.

GRNI and accounting impact

Receipt posting commonly debits inventory or expense and credits goods-received-not-invoiced (GRNI). The AP invoice clears GRNI and credits supplier payable. A service invoice may debit expense or WIP directly. Landed cost adds freight, duty, insurance, brokerage, and other approved components to inventory or expense.

For 480 cartons at USD 42 and rate 3.6725, base cost is AED 74,037.60. Allocate AED 7,900 duty and AED 4,500 freight by approved basis; final landed cost is visible by item and batch. Do not post duty to a generic expense when policy capitalises it into inventory.

Tax and withholding

Tax fields include code, taxable base, rate, amount, jurisdiction, import reference, exemption, and recoverability. Withholding records class, rate, authority, certificate, and payment reference. Manual override requires permission, reason, and audit.

Tax reporting reconciles invoice lines, GRNI, customs, withholding, and statutory returns. An invoice may be posted while tax certificate or customs evidence remains pending only if policy explicitly allows it and an exception owner exists.

Advances and prepayments

Supplier advances record supplier, PO/contract, amount, currency, bank, payment date, recovery rule, and approval. An advance debits supplier advance and credits bank; it is not expense or inventory until applied to an approved invoice or receipt.

Applying AED 20,000 advance to an AED 74,037.60 invoice reduces payable while retaining the advance reference. An unused advance remains visible in supplier statement and ageing. Refunds require approval and bank validation.

Approval and posting

Approval validates supplier active status, bank verification, duplicate invoice, source status, period, tax, currency, account mapping, budget, and permissions. High-risk events such as bank change or urgent payment require independent verification.

Posting debits inventory, expense, asset, or WIP and credits supplier payable, tax, withholding, and GRNI as configured. A posted invoice is corrected by credit/debit adjustment or reversal, never by editing history.

Payment and FX

Payment proposals select due invoices, supplier, company, bank, currency, discount, withholding, and cash availability. A payment batch has preparer, approvers, file ID, checksum, bank status, and rejection reason. A failed payment remains open with retry status.

For a USD invoice recorded at 3.6725 and paid at 3.6800, realised FX is posted on settlement. Month-end revaluation covers the open USD payable. Store rate source, date, and bank reference; never change the original invoice rate.

Supplier statement and close

The supplier statement shows opening, invoices, credits, advances, payments, unapplied amounts, disputes, and closing balance. Reconcile it to AP control and GRNI by company, branch, currency, supplier, and period.

Month end checks unbilled receipts, aged GRNI, duplicate invoices, open variances, withholding, tax, advances, bank, FX, and period locks. A receipt cannot remain indefinitely in GRNI without owner and ageing action.

API mapping and practice

Use immutable invoice ID, supplier ID, company, source PO/receipt, supplier invoice number, currency, tax, lines, and idempotency key. Decimal strings preserve money precision. A timeout retry uses the same key.

{"companyId":"company_uae","supplierId":"supplier_novabio","supplierInvoiceNo":"NB-INV-88210",
 "purchaseOrderId":"po_00041","receiptId":"grn_0041","currency":"USD","exchangeRate":"3.6725",
 "lines":[{"itemId":"med_ins_100","quantity":"480","unitPrice":"42.00","taxCode":"IMPORT"}]}

Practice: create a USD supplier invoice against a partial receipt, trigger a price variance, allocate landed cost, apply an advance, calculate withholding, approve a payment batch, settle at a different FX rate, and reconcile GRNI and supplier statement. Explain every field, status, permission, tax, cost, journal, API ID, and audit event.

Related: Purchase Order field guide, Inventory field guide, Journal Entry field guide, Treasury banking day, and API cookbook.

AP implementation worksheet

Use one supplier invoice and follow it from physical receipt to payment. Finance, procurement, warehouse, tax, and treasury should each confirm the fields in their control area.

Boundary	Required evidence	Demo value	Acceptance question
Supplier	Legal, tax, bank, blocked, currency	NovaBio GmbH / USD	Is the party safe to pay?
Source	PO, receipt, service confirmation	PO-0041 / GRN-0041	Is the claim supported?
Header	Company, branch, dates, terms	DGV UAE / Net 30	Is legal and ageing scope right?
Lines	Quantity, UoM, price, tax, account	480 cartons × USD 42	Does invoice agree with receipt?
Quality	Batch, certificate, acceptance	NB240901A / released	Is inventory usable?
Landed cost	Duty, freight, insurance, basis	AED 7,900 / AED 4,500	Is cost policy followed?
Approval	Variance, bank risk, decision	USD 1.20 variance	Is exception authorised?
Posting	GRNI, tax, withholding, payable	Balanced journal	Is liability complete?
Payment	Batch, checksum, bank status	PAY-2026-088	Can treasury prove settlement?
Close	GRNI, advances, statement, FX	Signed reconciliation	Are no balances orphaned?

Matching and variance examples

If the PO is 500 cartons, the receipt is 480 accepted, and the invoice is 480, the invoice may pass while 20 remain open. If the invoice is 500, the extra 20 must be rejected or approved as a documented exception; it must not increase stock. If the price changes from USD 42 to USD 43.20, show the USD 1.20 variance per carton, tolerance, owner, and decision. If the invoice tax code is domestic while the receipt is import, stop and resolve evidence before posting.

For 480 cartons at USD 42, goods value is USD 20,160. At 3.6725 the base value is AED 74,037.60. Add AED 7,900 duty and AED 4,500 freight only when the item policy capitalises those components. If allocated by value, show each batch’s share; if freight is expensed, post it to the approved freight account instead. The final inventory or expense value must reconcile to the component ledger.

Withholding and advance controls

Withholding is calculated from the configured tax base and supplier class, not from a manually typed payment deduction. Store rate, authority, certificate, period, and payment reference. A supplier advance debits advance and credits bank; it becomes expense, inventory, or asset only when applied to an approved claim. Test an advance larger than the invoice, an expired certificate, a changed supplier bank, and a refund to an unverified account.

Close and negative tests

Run duplicate supplier-invoice number, inactive supplier, missing receipt, rejected batch, invoice above receipt, tax mismatch, closed period, stale FX, unapproved variance, and changed idempotency payload tests. Each failure must be atomic and leave no partial GRNI, payable, tax, or stock journal. Close by reconciling AP sub-ledger, supplier statements, GRNI ageing, advances, withholding, tax, payment batches, bank, FX, and GL by company, branch, supplier, currency, and period.