Carriers integration

USPS + ReturnMate*

BetaThis integration is production-deployed and merchant-usable today. We're still expanding feature coverage and may iterate on behaviour as we learn from real usage. No service interruptions are expected.

USPS is the cost-effective default for US domestic returns, particularly for lightweight parcels under one pound where private couriers price uncompetitively. ReturnMate connects to USPS's modern REST API for label generation, live rate quoting, address validation, and free package pickup scheduling. Currently in Beta — production-ready for domestic US, with international service expansion landing in upcoming releases.

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§ 01 — Capabilities

What the integration does.

USPS REST API integration with API key authentication
Domestic US labels — Priority Mail, Ground Advantage, Priority Mail Express
International labels — First-Class Package International, Priority Mail International
Free Package Pickup scheduling — no fee for inbound returns at the customer's door
Live rate quoting at the customer portal
Address validation with ZIP+4 standardisation
Limitation: very restrictive on dangerous goods — lithium batteries face tight ground-only rules; route DG via FedEx or UPS

§ 02 — Use cases

How merchants use it.

Cost-effective US domestic returns

For non-DG returns under 1lb, USPS Ground Advantage is meaningfully cheaper than FedEx or UPS Ground. ReturnMate rate-shops at the customer portal and surfaces USPS as the default for qualifying parcels.

Free pickup at the customer's door

USPS Carrier Pickup is free for inbound returns when bundled with regular mail delivery. ReturnMate books the pickup automatically when the customer chooses USPS at the portal — no separate pickup fee, no separate booking flow.

Lightweight US-origin international

For US merchants with international customers, USPS First-Class Package International is the cost-effective option for sub-4lb parcels. Useful for returns from Canada, Mexico or APAC customers.

PO Box delivery support

USPS is one of the few US carriers that delivers to PO Boxes and APO/FPO military addresses. ReturnMate detects these address types and routes automatically when private couriers wouldn't accept them.

§ 03 — Setup

Connect USPS in minutes.

1
Register for USPS Web Tools / REST API access
Sign up at developer.usps.com for the modern REST API. Generate Consumer Key and Consumer Secret credentials.
2
Connect from ReturnMate
Settings → Carriers → USPS. Paste your API credentials. Tokens stored encrypted per shop.
3
Configure default services
Pick which USPS products to use (Ground Advantage for domestic, First-Class International for outbound international). Test with the USPS test environment before going live.

§ 04 — FAQ

Questions about USPS.

When should I use USPS over FedEx or UPS?

For US domestic non-DG parcels under one pound, USPS Ground Advantage is consistently the cheapest option. Above one pound the comparison gets closer and depends on your negotiated rates with the private couriers. ReturnMate rate-shops automatically — for any specific shipment, the cheapest accepting carrier is offered to the customer.

Does USPS handle lithium battery returns?

Very restrictively. USPS has tight rules on lithium batteries — installed batteries (in a device) up to specific watt-hour ratings can ship ground-only with proper labelling, but standalone batteries or air shipments are largely prohibited. For lithium-powered product returns, ReturnMate routes via FedEx or UPS, both of which have broader DG capability. USPS is blocked for those SKUs.

Is USPS Free Package Pickup actually free?

Yes, when the carrier is already delivering mail to the address. There's a separate USPS Pickup On Demand service for guaranteed pickup at a chosen time which carries a fee. ReturnMate uses the free Carrier Pickup by default and surfaces the paid On Demand option for time-sensitive cases.

When is USPS coming out of Beta?

Beta status reflects ongoing feature expansion (international service refinements, advanced rate optimisation, USPS Pickup On Demand integration), not stability concerns. The integration is production-deployed today for US domestic returns. Exit-Beta target depends on feedback from merchants currently using it; we'll move the badge once feature surface reaches parity with the AU carriers.

Also integrated.

Carriers

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