A structure definition snapshot is a complete representation of the structure definition, with all differential elements resolved. It represents the full content of the structure definition.
I've built this tool to allow you to easily generate snapshots for FHIR structure definitions with differentials. You can use the resulting structure definitions in your FHIR projects or for testing purposes.
Snapshot generation runs server-side and uses the ProfileUtilities class from the Java HAPI FHIR library.