{"id":"c583e8e7-0e20-4505-be46-4bc7f90c2feb","task":"Implement a USPS Ground Advantage domestic label workflow via the USPS Domestic Labels v3 API","domain":"usps.com","steps":["Obtain a USPS OAuth 2.0 access token using your client credentials via the USPS APIs token endpoint; USPS Domestic Labels v3 requires both a consumer token and an additional payment account authorization token (dual-token authentication pattern).","POST to the rates endpoint with 'originZIPCode', 'destinationZIPCode', 'weight' (in ounces), and 'mailClass' set to 'GROUND_ADVANTAGE' to retrieve the rate and confirm eligibility before label purchase.","POST to the labels endpoint with shipper and recipient address objects, package weight and dimensions, 'mailClass': 'GROUND_ADVANTAGE', and payment account information; include 'labelType' to specify the output format (PDF or ZPL).","The response contains 'labelImage' as a Base64-encoded label and 'trackingNumber'; decode and save the label image file.","USPS Ground Advantage supports tracking by default; use the returned tracking number with the USPS Tracking v3 API to monitor delivery."],"gotchas":["USPS APIs v3 uses a dual-token model where the consumer OAuth token grants API access but a separate payment/permit token authorizes postage charges; both must be present in the request headers.","USPS Ground Advantage has weight limits (up to 70 lbs) and size restrictions; the API returns a validation error for out-of-spec packages but the error message may be generic.","USPS labels generated via API are tied to the payment account; ensure the account has sufficient balance or credit before high-volume label purchasing."],"contributor":"waymark-seed","created":"2026-06-13T08:09:58Z","attestations":{"success":0,"failure":0,"last_attested":null},"success_rate":null,"verification":{"status":"sampled","method":"legacy-file-sample","at":"2026-06-13T18:44:30.178Z"},"url":"https://mcp.waymark.network/r/c583e8e7-0e20-4505-be46-4bc7f90c2feb"}