Knowing how to invoice the government gets you the paperwork right. It does not tell you which system actually moves your invoice to a payment. That is WAWF or IPP, depending on who you are billing, and the mechanics of each one determine how fast you get paid.
WAWF is DoD's system, and it is now inside PIEE
Wide Area Workflow is the Defense Department's electronic invoicing and receipt system. It has been folded into the Procurement Integrated Enterprise Environment, so you will see both names depending on which page you land on, but it is the same login and the same workflow. If your contract clause references DFARS 252.232-7003, WAWF submission is not optional. It is how you get paid.
The mechanics: you register for a PIEE account tied to your CAGE code, then submit an invoice against the specific contract and delivery order number. For most contracts you will submit a "combo" document, an invoice and receiving report together, so the government official who accepts your goods or services and the one who approves payment are working off the same record. Once that government acceptance happens inside WAWF, the payment clock starts for DFAS to release funds (DLA, Wide Area Workflow).
The part people get wrong: WAWF rejects on mismatches, not on judgment calls. Contract number, CAGE code, pay office, and line item quantities all have to match the contract exactly. A typo in the delivery order number does not get a phone call. It gets bounced back, and you resubmit from zero.
IPP is Treasury's system, and it is civilian agencies
The Invoice Processing Platform is run by the Bureau of the Fiscal Service and is the default for most non-DoD federal agencies. Treasury policy requires most agencies to use it for commercial invoices unless they have a waiver (Bureau of the Fiscal Service, IPP). If your contracting officer sits at GSA, VA, HHS, or most other civilian agencies, you are probably submitting through IPP, not WAWF.
IPP works off the purchase order the agency already loaded into the system. You register, match your invoice to that PO, and submit. From there IPP routes it through the agency's approval chain automatically, with a payment notification service that tells you where the invoice actually sits instead of making you call and ask. That visibility is the real difference from WAWF: IPP shows you the approval workflow, WAWF mostly shows you accepted or rejected.
Progress payments change the payment cadence entirely
Everything above assumes you invoice after you deliver. Larger contracts, especially manufacturing and long-lead production work, do not wait that long. Under FAR 52.232-16, you can invoice for costs incurred as the work progresses, not just at delivery. Small businesses get a customary 85 percent progress payment rate, and DoD contracts often set that at 90 percent (FAR 52.232-16, Progress Payments).
Performance-based payments work differently. Instead of billing against costs, you bill against milestones defined in the contract, tied to a schedule, not to how much you spent. Either way, these still route through WAWF or IPP the same as a standard invoice. The system does not change. What changes is when you are allowed to submit and how much of the contract value each submission represents.
If you are pricing a contract that qualifies for progress payments, that financing structure is worth modeling before you bid, not after you win. It changes your cash position for the life of the contract. It is also the kind of deadline that is easy to lose track of once you hold more than one active contract, which is part of why we built tracking into the pipeline itself rather than leaving it to a spreadsheet.
Related reading
- How to Invoice the Federal Government
- How to Track Your Federal Contract Deadlines Without Missing One