Use the QuickBooks Online Change Data Capture (CDC) endpoint to detect recently modified entities

In-depth guide

Steps

1. GET /v3/company/{realmId}/cdc?entities=Invoice,Payment,Customer&changedSince={ISO8601 timestamp}
2. Parse the 'CDCResponse' array; each entry contains an entity name and a 'QueryResponse' listing changed objects of that type
3. Detect deleted records by checking for objects where 'status' is 'Deleted' in the response
4. Store the high-water-mark timestamp (use the response's 'time' field, not your local clock) for the next CDC call
5. Request multiple entity types in one CDC call to reduce API round-trips, but check that all listed entity types support CDC
6. Implement idempotent upsert logic downstream, as the same record may appear in multiple CDC windows if it is updated repeatedly