Punchout is the round trip that lets a buyer browse a supplier catalog from inside their own procurement tool, then return the selected cart to the requisition workflow. SAP standardised the ERP side of the round trip with Open Catalog Interface (OCI): a simple HTTP form-POST protocol where the catalog returns the picked items as NEW_ITEM-* form fields. This demo shows in real time what the OCI gateway would post back to your ERP, plus the equivalent cXML PunchOutOrderMessage that Ariba uses in the same role.

<form method="POST" action="HOOK_URL">

  <button type="submit">Return to procurement</button>
</form>

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE cXML SYSTEM "http://xml.cxml.org/schemas/cXML/1.2.069/cXML.dtd">
<cXML payloadID="1783269309905.916329@ediverse.io.demo" timestamp="2026-05-14T12:00:00+00:00" xml:lang="en-US">
  <Message>
    <PunchOutOrderMessage>
      <BuyerCookie>EDIVERSE-DEMO-COOKIE-1783269309905</BuyerCookie>
      <PunchOutOrderMessageHeader operationAllowed="create">
        <Total>
          <Money currency="EUR">0.00</Money>
        </Total>
      </PunchOutOrderMessageHeader>

    </PunchOutOrderMessage>
  </Message>
</cXML>

How it works

1. The buyer clicks "Shop from catalog X" inside their ERP (SAP, Coupa, Ariba…).
2. The ERP redirects the browser to the catalog URL with a HOOK_URL parameter — the address the cart must return to.
3. The user browses, picks items. This demo simulates that step.
4. On checkout, the catalog generates an HTML form that POSTs to HOOK_URL with all NEW_ITEM-* fields. That's what you see on the right.
5. The ERP receives the POST, parses the fields, creates a purchase requisition.

OCI vs cXML

OCI and cXML play the same role, but OCI uses a flat HTTP form-encoded payload while cXML uses a structured XML message (PunchOutOrderMessage). Many catalogs expose both to match the ERP on the other side — SAP MM prefers OCI, Ariba prefers cXML. This demo produces both from the same cart so you can see the line-by-line correspondence.

OCI 4.0 vs OCI 5.0

OCI 5.0 mainly adds the contract reference (NEW_ITEM-CONTRACT[i] and NEW_ITEM-CONTRACT_ITEM[i]) to attach the line to a negotiated framework, plus a few extras like NEW_ITEM-EXT_QUOTE_ID. Everything else is identical to OCI 4.0, which is still very widely deployed. The demo toggles between the two versions and hides the 5.0-specific fields when you pick 4.0.

Privacy

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Related documentation

• OCI standard (concepts and history)
• cXML standard (overview)
• cXML PunchOutOrderMessage
• cXML PunchOutSetupRequest