Advance ruling in GST provides binding tax certainty for applicant and jurisdiction, enabling pre- and post-transaction clarification and appeals. Advance ruling under GST permits a registered person or applicant to obtain binding clarification from the Authority for Advance Ruling on specified matters-classification, notification applicability, time and value of supply, input tax credit admissibility, tax liability, registration requirement and whether an activity is a supply. Rulings are binding only on the applicant and the concerned jurisdictional officer while facts, law or circumstances remain unchanged; appeals lie to the Appellate Authority for Advance Ruling with prescribed forms, fees, signatures and statutory timelines.