ONDC: one order, four companies, no shared database

How an open commerce network works when buyer apps, seller apps and couriers are different companies with no shared database: 500 million transactions by 25 July 2026 and 218 million in FY 2025–26, but the load is search, so buyer apps cache catalogues and seller apps check live stock at select; every message signed against a registry whose /lookup limit is a recommended 7,600 a minute; an order named by the buyer app, idempotent confirms, and ONDC's hold-then-release rule with 999 and 998 cancellations for every silence; logistics as a second transaction the seller app orchestrates; settlement that moves money only when both sides' instructions match; and complaints that cross three companies with 48-hour and 30-day deadlines.