cXML is an XML-based protocol for business-to-business procurement transactions — purchase orders, order confirmations, invoices, and the PunchOut session that hands a buyer into a supplier’s catalog and returns a filled cart. Created by Ariba in 1999, it remains the dominant integration format between e-procurement suites and their suppliers.
cXML
cXML is the format enterprise procurement actually runs on. Ariba published it in 1999, and twenty-five years later it is still how a buying organization’s e-procurement suite exchanges purchase orders, order confirmations, ship notices and invoices with its suppliers.
- Transaction documents -
OrderRequest,ConfirmationRequest,ShipNoticeRequest,InvoiceDetailRequestand their responses cover the procure-to-pay cycle. - PunchOut - The distinctive piece: a buyer clicks through from their procurement suite into the supplier’s own catalog, shops there, and the cart returns to the buyer’s workflow for approval. See also OCI, SAP’s equivalent.
- HTTP POST of XML - Documents move over ordinary HTTPS, which makes cXML far closer to a web API than EDI ever was.
- De facto rather than de jure - No neutral standards body governs it; it is a vendor specification that the market adopted.
cXML matters to API research because it is the closest thing enterprise procurement has to a shared contract, and it sits in an awkward middle. It moves over HTTP like an API and it is documented publicly, but it is document-exchange-shaped rather than resource-shaped, and there is no OpenAPI for it. The State of Supply Chain APIs scored procurement and sourcing as the market’s largest segment — 204 providers — averaging 20.7 with under a quarter publishing a machine-readable contract. The integration standard is present and widely used; the contract a developer or an agent could call is not.
Referenced in API Evangelist papers
This standard shows up in my published research. These reports read the machine-readable evidence provider by provider — and put this standard in the context of a real sector.
The State of Supply Chain APIs
Eight providers in the cohort integrate over cXML — Coupa, Ariba, CDW, SciQuest, United Rentals among them — in the report's largest segment, procurement and sourcing, which averages 20.7 with 22.5% publishing a spec.
