Both endpoints return vehicle identity, but they start from different keys. Choosing the right one depends on what you hold, how stable the identifier is, and how much confidence you need.
Plate lookup: what humans see
Plates are printed on the car, so they're the natural input at a dealership, auction or marketplace. A plate lookup answers "what is currently registered to this plate?" The catch: plates can be transferred, personalized or reissued, so the answer reflects registration state — not permanent identity.
VIN lookup: the stable key
The 17-character VIN is stamped into the vehicle and stays with it for life. VIN decoding returns manufacturer, model year, body, engine and more, independent of any plate. It's the better key for records, inspections and cross-border workflows.
When to use both
The strongest products use both: capture the plate for convenience, then resolve the VIN and store it as the canonical key. That's why CSNB's AU Rego Check accepts either input in a single parameter and routes automatically.
Confidence matters
Registration records and catalogue data can disagree. CSNB marks each
response with a confidence value in _meta, so
your code can treat high-confidence catalogue matches differently from
reduced-confidence parsed results.
Start building
Try both inputs against the AU Rego Check API — plate and VIN work through the same endpoint.