OCI and cXML are the two most widely used standards for PunchOut integrations in enterprise procurement.
Both enable buyers to access supplier catalogs from procurement systems, but they differ significantly in structure, data exchange, and technical implementation.
This guide explains the differences between OCI and cXML, how each standard works, and when one is preferred over the other in PunchOut integrations.
What Is OCI (Open Catalog Interface)?
OCI (Open Catalog Interface) is a PunchOut standard originally developed by SAP to integrate external supplier catalogs with SAP-based procurement systems.
OCI uses URL-based communication and parameters passed through HTTP requests to establish a PunchOut session and transfer shopping cart data back to the buyer system.
OCI is commonly used in:
- SAP ECC
- SAP S/4HANA
- SAP SRM environments
What Is cXML (Commerce XML)?
cXML (Commerce XML) is an XML-based standard developed by Ariba and widely adopted across modern procurement platforms.
In a cXML PunchOut integration, structured XML messages are exchanged between the procurement system and the supplier catalog to manage sessions, authentication, and cart transfer.
cXML is commonly used in:
OCI vs cXML: Key Differences
Although both standards support PunchOut workflows, they differ in technical approach.
| Feature | OCI | cXML |
|---|---|---|
| Origin | SAP | Ariba |
| Data format | URL parameters | XML messages |
| Session handling | Client-based | Server-based |
| Security model | Simpler | More structured |
| Extensibility | Limited | High |
| Typical platforms | SAP ECC / S4 | Ariba, Coupa, Jaggaer |
PunchOut Flow with OCI
A typical OCI PunchOut process works as follows:
- The buyer launches the supplier catalog from the procurement system
- OCI parameters are passed via URL
- The supplier catalog opens a PunchOut session
- The buyer shops in the catalog
- Cart data is returned to the procurement system via OCI fields
OCI relies heavily on browser-based communication and parameter mapping.
PunchOut Flow with cXML
A cXML PunchOut process follows a more structured exchange:
- The procurement system sends a cXML PunchOutSetupRequest
- The supplier system validates the request
- A secure session is established
- The buyer shops in the catalog
- The cart is returned using a cXML PunchOutOrderMessage
This approach provides stronger validation and greater flexibility.
When to Use OCI
OCI is typically the right choice when:
- The buyer uses SAP-based procurement systems
- Integration requirements are relatively simple
- Legacy SAP environments are involved
- URL-based PunchOut is already supported
OCI remains widely used due to its strong presence in SAP ecosystems.
When to Use cXML
cXML is preferred when:
- Buyers use modern cloud procurement platforms
- Complex cart data and validation are required
- Multiple buyers or systems are involved
- Security and extensibility are priorities
cXML is the dominant standard in multi-platform enterprise environments.
Supporting Both OCI and cXML
Many suppliers work with buyers using different procurement systems.
In these cases:
- Supporting both OCI and cXML avoids integration limitations
- A middleware or PunchOut Gateway can normalize both standards
- Suppliers can maintain a single e-commerce platform
This approach reduces maintenance effort and improves scalability.
Frequently Asked Questions About OCI and cXML
Is cXML replacing OCI?
No. OCI remains widely used in SAP environments, while cXML dominates cloud procurement platforms. Both standards coexist.
Is cXML more secure than OCI?
cXML offers more structured validation and messaging, but both can be implemented securely when designed correctly.
Can a single catalog support both OCI and cXML?
Yes. Many suppliers use a PunchOut Gateway or middleware layer to support both standards from a single catalog.
Do suppliers choose OCI or cXML?
The buyer’s procurement system usually determines which standard must be supported.
Key Takeaways
OCI and cXML are both essential PunchOut standards, each suited to different procurement ecosystems.
Understanding their differences helps suppliers design scalable integrations and support enterprise buyers effectively.
