UBL is an OASIS standard defining royalty-free XML schemas for the common documents of trade — order, despatch advice, receipt advice, invoice, credit note and dozens more — providing the shared document model that Peppol and several national e-invoicing regimes profile.
UBL
UBL is the OASIS-governed library of XML schemas for the documents businesses actually exchange — orders, despatch advices, receipt advices, invoices, credit notes, statements, catalogues. It is published royalty-free and standardized as ISO/IEC 19845.
- A document library, not a protocol - UBL says what an invoice contains; it says nothing about how it travels. Peppol supplies the network.
- Profiled in practice - Raw UBL is permissive, so real deployments constrain it: Peppol BIS, EN 16931 for European e-invoicing, and national variants.
- Modelled on real trade - The document set follows the buy-ship-pay progression that UN/CEFACT also models.
- Widely mandated - Several national e-invoicing regimes require a UBL-derived format.
UBL is a useful counterexample to the assumption that these markets lack semantics. The trade document model is fully specified, freely available, internationally standardized and two decades old. What The State of Supply Chain APIs found missing is not the model — it is any provider exposing it as something a machine can query rather than a file it can receive.
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
The schema layer under Peppol, used by Tradeshift and Qargo — a fully specified document model for trade, and one no provider in the cohort exposes as a callable contract.
