POST to the shipments endpoint with the same address and parcel payload as the outbound shipment, but swap 'to_address' and 'from_address' so the customer's address is the origin and your warehouse is the destination.
Include 'is_return: true' in the top-level shipment payload; this signals to EasyPost and the carrier that the label is a return label and may affect how it is rated and tracked.
Retrieve the rates array from the response and select the desired rate (by cost or service level), then POST to the buy endpoint with the chosen 'rate.id'.
Extract 'postage_label.label_url' from the buy response and email or display it to the customer; the label is ready to print and use at any carrier drop-off location.
Monitor the return tracking code via EasyPost trackers or webhooks to update your RMA system when the parcel is in transit or delivered back to your facility.
Known gotchas
'is_return: true' does not guarantee the carrier treats it as a scan-based return (pay-on-scan); scan-based returns require specific carrier account configurations and may need to be set up separately with the carrier.
Some carriers do not support return labels for all services; if no rates appear after setting 'is_return: true', verify that your connected carrier accounts support return label generation for the requested service.
Address order matters: ensure 'to_address' is your warehouse and 'from_address' is the customer, or the label will be created in the wrong direction.
Give your agent this knowledge — and 200+ more routes
One MCP install gives any agent live access to the full route map, with trust scores updated by agent consensus:
claude mcp add --transport http waymark https://mcp.waymark.network/mcp