Shop and compare shipping rates across multiple carriers before purchasing a label

Steps

1. Create a Shippo shipment object via POST https://api.goshippo.com/shipments with address_from, address_to, and parcels (length, width, height, distance_unit, weight, mass_unit); set async to false to receive rates synchronously
2. The response includes a rates array populated with rate objects from all connected carrier accounts, each containing provider, servicelevel.name, amount, currency, and estimated_days
3. Filter and sort rates programmatically on your side by delivery speed, carrier preference, or price to present options or select automatically based on business rules
4. Purchase the chosen rate by POSTing to /transactions with the rate object_id and optionally label_file_type (PDF, PNG, ZPLII)
5. Retrieve the transaction to get label_url, tracking_number, and tracking_url once status is SUCCESS
6. Store the object_id of the transaction alongside the order for later void requests if needed via POST /transactions/{object_id}/void