Non-PO Service Invoices: Who Confirms the Work Before AP Pays?

The agency's invoice looks right. The supplier is approved, the amount matches its contract, and the payment terms are clear. AP still cannot tell whether the campaign deliverable was accepted. That question belongs to the person who received the work, not the person who keyed the invoice.

A non-PO invoice arrives without a purchase order to match against. For a service, the missing PO and the absence of a physical goods receipt are separate issues. AP needs evidence of purchase authorization, evidence that the billed service was performed or the period was covered, and approval of the amount to release. An accurate invoice alone supplies none of those confirmations.

Key Takeaways

• A non-PO service invoice needs an accountable service owner who can confirm performance, not just an AP approver who can confirm invoice fields.

• Record authorized scope, billed milestone or period, delivery evidence, amount accepted, and the named approver's dated decision.

• If only part of the work is accepted, document the accepted and disputed portions before choosing a payment or revised-invoice path under the contract and company policy.

• Do not create a retroactive PO merely to make an exception look like a routine match.

What replaces a goods receipt when the purchase is a service?

A goods receipt tells AP that physical items arrived. For consulting, maintenance, implementation, or creative work, the equivalent control is a record that someone with firsthand knowledge reviewed what was performed. Call it a service acceptance record. It can live in a workflow, a work-order system, or an attached approval form; the control is the evidence and decision, not the name of the file.

A useful record has five fields:

This is a proposed buyer control, not a claim that any invoice platform independently verifies a vendor's work. A product can capture and route the invoice; only the business owner can judge whether the output met the agreement.

The distinction has a useful systems analogy. SAP describes formal service acceptance before invoice verification. Its service entry sheet is tied to a purchase order, though. Borrow the idea of an acceptance step for non-PO work; do not tell AP it can perform a two-way or three-way match against a PO that does not exist.

Which evidence proves a milestone was delivered?

Choose evidence that fits the service. A signed design review can support a creative milestone but does not prove the next campaign launched. An approved timesheet supports hours worked but not necessarily a promised outcome. A closed maintenance ticket supports completion of a specific job, while a contract owner's dated attestation may be the practical record for advisory work with no tangible deliverable.

The owner should say what was checked. "Approved" without a service period, deliverable, or exception note leaves the next reviewer guessing. For recurring work, keep the contract and the period-specific acceptance together; a prior month's approval should not silently authorize the next month's invoice.

Before attesting, the owner can make three quick comparisons:

• Match the invoice's service period or milestone to the agreement. A bill for a completed phase is different from a deposit due before work begins.

• Open the evidence rather than relying on its filename. A ticket marked closed may still have unresolved customer acceptance criteria.

• Note any qualifications in the decision. "Accepted for testing" is not the same as "accepted for final payment" if the contract makes testing a condition.

If the agreement calls for payment on a date regardless of a later deliverable, record that term instead of inventing a performance condition. The acceptance record should explain the actual obligation, not rewrite it.

Who can authorize and accept a non-PO service invoice?

The requester may authorize a purchase but not be the person who can confirm the service. AP should map those roles before the first invoice reaches the queue. The exact thresholds and separation rules come from your organization's policy.

A purchase requisition and procure-to-pay workflow can put authorization before the commitment. When work is already underway without that document, AP needs an authorized exception path, its owner, and a separate service-acceptance decision.

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What if the requester and service recipient are the same person?

That may be ordinary in a small department, but it concentrates the purchase and acceptance decisions. A second-level budget owner, controller, or procurement reviewer can check the contract, evidence, and exception before release. Use that review when your policy calls for it; there is no universal dollar threshold or universal private-sector rule requiring a particular approver.

Keep the second decision distinct. Forwarding the same person's "looks fine" email to AP twice is not independent review. The invoice approval workflow should show who made each decision and when.

A practical exception route gives each person one job:

• The requester explains why there is no PO and attaches the contract or other authorization.

• The service recipient identifies what was delivered and what, if anything, remains open.

• The exception owner decides whether company policy permits payment and records the reason; AP releases only the approved amount.

That route is especially useful for recurring consulting work. The first invoice can establish the exception, but each later invoice still needs the correct service period and whatever ongoing acceptance the agreement requires.

When should AP hold, partially approve, or pay the invoice?

Decide against the billed obligation, not against whether the vendor seems trustworthy. A legitimate supplier can bill ahead of acceptance, duplicate a service period by mistake, or disagree about scope. The service owner resolves performance; AP controls payment release.

Suppose an implementation partner invoices $12,000 for a milestone, but the service owner accepts only $8,000 of completed work. The other $4,000 is awaiting a test result. Record the accepted scope and amount, the held scope and amount, and who will resolve the test. AP should not mark the entire $12,000 as approved just because the invoice total is correct. Depending on the agreement and payment system, AP may request a corrected invoice, a credit, or an authorized partial-payment process; it should not assume that paying part of the original invoice is always allowed. Tell the supplier which portion is disputed and what evidence would clear it.

Then link the later resolution to the original invoice. If the supplier issues a revised invoice or rebills the held work, the duplicate-payment check must account for the amount already paid or still reserved. Otherwise a sound acceptance decision can still end in two payments for one milestone.

Timing deserves an explicit owner. The invoice due date does not disappear while a team debates acceptance, and an uncommunicated hold may create a supplier dispute. AP should send the service owner a decision deadline, tell the supplier which lines are under review, and record whether the contract allows the undisputed portion to be released. If the service owner misses the deadline, escalate it under the normal approval policy instead of silently approving the full bill or letting it age in an unassigned queue.

When does a missing PO require an exception rather than a retroactive PO?

Follow the company's purchasing policy. An emergency repair, an approved contractual renewal, and an unauthorized order may all arrive without a PO, yet they warrant different decisions. Capture who authorized the commitment, why the normal route was missed, and what procurement or controller review is required. If policy calls for a PO after the event to track the balance, label it accurately; never backdate or manufacture one to conceal the break. For the generic distinction between the documents, see purchase order versus invoice.

What should the audit trail contain before payment release?

The five-field record answers the service question, but AP also needs the invoice-control trail. Keep the authorization reference or exception, invoice number and supplier, service period, acceptance evidence, approved and held amounts, approver and decision date, dispute resolution, duplicate-check result, and payment status together. If remit-to details changed, route that change through the separate supplier-verification process before paying.

A concrete example of field-level discipline comes from Texas A&M's non-PO invoice checklist. It calls for supplier, invoice number, terms, remit-to verification, attachment, accounting codes, and total review. That is one institution's procedure, not a universal policy. Federal prompt-payment rules likewise illustrate how specific the supporting documentation and acceptance terms can be for federal contracts; private companies should follow their own contracts and applicable policies rather than borrowing federal rules wholesale.

The useful test is whether a reviewer who did not attend the project meeting could reconstruct the decision. If they see only a vendor invoice and a green approval badge, they cannot tell which work was accepted or why a disputed balance was paid.

Before changing an invoice to payable, AP can run a short release check:

• Compare supplier, invoice number, amount, and service period with prior invoices and credits.

• Confirm that the accepted amount in the service record equals the amount scheduled for payment.

• Check that any held balance has an owner and a next action; do not let it disappear into a generic "approved" status.

• Preserve the supplier communication and exception decision with the invoice, so a later revised bill can be reconciled to this one.

The accounts payable process may already have a duplicate and supplier check. The service-specific addition is the work-acceptance decision and its link to the amount released.

How can AP route verified service invoices through a controlled workflow?

Capture the supplier's invoice once, send it to the person who can attest the service, and keep the exception decision attached before payment approval. Ask a provider to demonstrate the workflow with a real non-PO example. Who can approve or hold it? What happens to a partially accepted amount? How does the ERP record the final state?

Corpay invoice automation describes invoice data capture, customizable approval routing, visibility into invoice status, and ERP synchronization. Those capabilities can help move the record and decision through AP. They do not establish that Corpay creates a non-PO service entry sheet or decides whether the work was done. Ask a Corpay specialist to show how your acceptance evidence and exception policy would be configured before you rely on the workflow for service invoices.

Frequently Asked Questions

Is a non-PO invoice always an exception?

No. Some organizations deliberately permit certain invoice categories without a PO. Whether a specific service invoice needs exception approval depends on the purchasing policy and whether the work was authorized.

Can a service invoice be approved without a goods receipt?

Yes, if the applicable process allows another record of service acceptance. A signed milestone, approved work order, timesheet, or named owner's attestation can support the decision. AP still needs invoice and payment controls.

Is a service entry sheet the same as a goods receipt?

Not exactly. In SAP's documented PO-backed service workflow, the sheet records performed services and acceptance before invoice verification. It is a useful model for the control, not a universal document required for every non-PO invoice.

Who signs off on work performed?

The business owner or service recipient who can assess the work should make the acceptance decision. A budget owner or controller may also need to approve the purchase or an exception under company policy. AP checks the record and routes payment. It cannot observe the service itself.

Can AP pay only the accepted portion?

Sometimes, but the contract and payment process determine how. Record accepted and held amounts first, then use an authorized partial payment, corrected invoice, or credit path. Keep subsequent invoices tied to that decision so the same work is not paid twice.

David Luther

Product Marketing Program Manager

David Luther, MBA is a product marketing program manager with years of experience in commercial banking, finance, and technology sectors, with research and writing appearing in financial publications.

AP Automation

Procure-to-Pay