Overview
ISO 18626:2021 - "Information and documentation - Interlibrary loan transactions" - is the third-edition international standard that defines a modern, web-friendly protocol for handling interlibrary loan (ILL) requests and message exchanges. Designed to replace older ISO ILL protocols (ISO 10160 / ISO 10161), ISO 18626 specifies the structure and flow of ILL transactions using XML and web service–compatible transports to support current library resource-sharing workflows.
Key technical topics and requirements
- Three core message types and confirmations: Request, Supplying Agency Message, Requesting Agency Message - each paired with an immediate confirmation to acknowledge receipt.
- Message content and structures: Defined data elements, complex types, and Error Data to report problems detected on receipt.
- Code lists: Uses Open Code Lists (extensible schemes) and Closed Code Lists (normative in the standard). Annex B clarifies open-code use and core lists to support interoperability.
- Format and transport: XML schemas and guidance for HTTP/HTTPS transport (including message headers, character representation and privacy considerations) are specified; Annex C contains XML schema references.
- Conformance and profiles: Conformance requirements are included and Annex F offers guidance on using profiles; Annex A links to implementation resources.
- Operational features: DeliveryMethod/DeliveryInfo (formerly SentVia), ItemFormat/PreferredEdition, RetryInfo for negotiation, and handling of consortia are addressed (Annexes G and H).
- Interoperability considerations: Alignment with ANSI/NISO Z39.83 and references to standard identifiers and conventions (ISBN, ISSN, ISIL, ILII, DOI, ISNI, ISO date/time, UTF‑8).
Practical applications and who uses it
ISO 18626 is intended for organizations and professionals involved in library resource sharing:
- Academic, public, special and national libraries implementing interlibrary loan services.
- Library consortia coordinating cross‑institutional ILL workflows.
- Library systems vendors and developers building ILL modules, web services or middleware using XML/HTTP.
- Archives, museums and commercial document suppliers that act as supplying or requesting agencies.
- Systems integrators implementing standards-based interoperability between ILS, discovery layers and resource‑sharing platforms.
Benefits include simpler implementation compared to legacy ILL protocols, modern web-service compatibility, and standardized message semantics to improve automation and reduce errors in interlibrary lending.
Related standards
Keywords: ISO 18626, interlibrary loan, ILL transactions, resource sharing standard, XML ILL, library interoperability, HTTP/HTTPS ILL, open code lists.
