Yes, I find out that. But I wanted to have the JSON serialization to be context-dependant. And that's what I achieved by means of the custom mappings. Again, kudos for making it so fast and memory-savvy, being stream based with no internal transformations makes it almost a basic printOn: aStream. One question that remains is... how to map the same accesor/instVar to more than one attribute. eg. neoJsonMapping: mapper mapper for: self do: [:mapping | mapping mapAccessor: #reference. "full" (mapping mapAccessor: #reference to: 'reference-id) valueSchema: #ReferenceId "just its ID" ]. mapper for: #ReferenceId customDo: [:mapping | mapper encoder: [:obj | obj id printString ] "..." ] If I do that, I end up having the full reference twice. Regards! -- View this message in context: http://forum.world.st/NeoJSON-Mappings-tp4677077p4677288.html Sent from the Pharo Smalltalk Users mailing list archive at Nabble.com.