@james_lloyd NetSuite provides the External ID (

externalid

) field on nearly every record type. The field is intended to store a record's PK from an external system to keep the two systems in sync. As far as generating the actual ID, you could either generate it in NetSuite yourself with SS, or let the external system create it then push the ID back to NetSuite into the external ID, either with a RESTlet or with Web Services. I don't know of a non-SS solution.