cXML vs OCI: which punchout standard does your buyer need?

If a large buyer asks you to “support punchout”, the next question is always: cXML or OCI? Both do the same job. The buyer’s employee opens your shop from inside the procurement system, fills a basket, and the basket travels back into the procurement system for approval. They differ in how the two systems talk to each other.

cXML

cXML is an XML standard. It is used by platforms such as SAP Ariba, Coupa and Jaggaer.

1. The buyer’s system sends your server a PunchOutSetupRequest, an XML message with the buyer’s identity, a BuyerCookie that identifies the session, and the URL to return the basket to.
2. You answer with a PunchOutSetupResponse containing a start-page URL for your shop.
3. When the user finishes, your shop sends the basket back as a PunchOutOrderMessage, an XML document with item lines, prices, units and currency.

The first exchange is server to server, so it is easy to log and to test.

OCI

OCI (Open Catalog Interface) comes from SAP and is common in SAP ERP and SRM landscapes.

1. The buyer’s system opens your shop URL in the user’s browser with a few parameters, the most important being HOOK_URL, the address the basket must be sent back to.
2. The user shops.
3. Your shop returns the basket as an HTML form posted by the browser to HOOK_URL, using numbered fields such as NEW_ITEM-DESCRIPTION[1], NEW_ITEM-QUANTITY[1], NEW_ITEM-PRICE[1].

The practical differences

	cXML	OCI
Format	XML documents	Form fields
Setup	Server-to-server request	Browser opens a URL
Commonly used with	Ariba, Coupa, Jaggaer	SAP ERP / SRM
Return path	PunchOutOrderMessage	Form post to HOOK_URL

Which one do you need?

You do not choose. The buyer’s system decides, and a supplier who sells to several large buyers usually ends up supporting both. That is the main reason to put the translation in a separate middleware layer: your shop keeps one internal basket format, and the middleware produces cXML or OCI depending on the buyer.

Not sure what your buyer uses? Ask their procurement team for the “punchout supplier onboarding” document. It states the standard and the fields they expect.