Purchase labels in batches with Shippo for high-volume shipping

Steps

1. Create a Batch object via POST to https://api.goshippo.com/batches with an array of shipment objects (each containing from/to addresses, parcels, and carrier/service level); a single batch supports up to 10,000 shipments.
2. Poll the batch object's status field (VALIDATING → VALID or INVALID) before purchasing — Shippo asynchronously validates each shipment in the batch and marks individual entries as valid or invalid.
3. Review invalid shipments in the batch response and correct or remove them; you can add additional valid shipments to a VALID batch before purchasing.
4. Trigger label purchase by sending an empty POST to https://api.goshippo.com/batches/{BATCH_OBJECT_ID}/purchase; this is an asynchronous operation.
5. Listen for the batch_purchased webhook event (or poll the batch status) to confirm purchase completion; downloaded labels are returned as merged PDFs with up to 100 labels per file.
6. Reconcile the purchased batch against your order list; shipments that failed purchase (e.g., carrier rejection) appear with an error status and must be re-submitted as individual shipments or a new batch.