Returns API Coverage Across 9 Shipping Platforms

Ask ten integration engineers what "returns API" means and you'll get ten different answers. Some mean a single POST call that spits out a scan-based label. Others mean a branded portal where a shopper can pick a reason code, choose a refund method, and get a QR code for the nearest parcel locker. A few mean the whole loop: label, carrier scan, automated refund trigger back into the ERP. These are not interchangeable capabilities, and vendor landing pages rarely draw the line clearly. This post is a documentation audit, not a load test: every row in the matrix below traces to a public API reference, help center article, or changelog entry, pulled in October 2026. Where a capability isn't documented anywhere we could find, it's marked "Not published." Nothing here is inferred or extrapolated from a sales page.

Method: what we checked, and what we didn't

We read the public developer docs, support articles, and changelogs for nine platforms that show up repeatedly in shipper RFPs: Shippo, EasyPost, Sendcloud, nShift, ShipStation API (formerly ShipEngine), ClickPost, AfterShip, Cargoson, and ShippyPro/ProShip. For each one we looked for four specific things: whether a return label can be generated through the API itself, whether label-free or QR-code returns are documented, whether the vendor publishes a self-service consumer-facing returns portal, and whether paid-returns (charging the shopper a return fee) is a documented feature. We did not run live sandbox calls against any of these accounts for this report, so none of the figures below reflect latency, success rate, or webhook delay. That's a separate test, and we flag it as a follow-up at the end.

The feature matrix

Here's what's actually published, side by side. Where a vendor's own marketing page contradicts its API docs, we went with the API docs and noted the discrepancy.

A few of these rows deserve unpacking. All Shippo return labels are scan-based, available for USPS, FedEx, and UPS shipments only, and you can only generate return labels for the same carrier that your outbound shipment was sent with. That's a tighter scope than it sounds, because these labels are free to print and you won't get charged unless it gets used. Shippo's own API changelog also shows QR returns were added later than people assume: you can now use QR codes for UPS, and generated QR codes can be brought to a carrier location to print labels for outbound and return shipments. That's a 2022 addition, carrier-specific, not a general label-free flow across the catalog.

EasyPost documents the QR/email pattern directly: you can use the EasyPost Shipping API to print return labels and include them in outbound shipments or send them to customers via QR code or email. But the portal itself isn't EasyPost's job. EasyPost partners with top-notch return management platforms like Loop, ReturnGO, and ReturnLogic to build the shopper-facing experience. On billing, EasyPost's pay-on-delivery model means you only pay for return labels that are used, saving on unused labels and skipping billing adjustments.

Sendcloud is the one platform here that documents both halves of the problem as separate, named products. The Returns Portal API lets you let customers manage their own returns by building a custom version of the Return Portal, and you can combine this with the paid returns feature to proactively charge a return fee when needed. Separately, the Returns API lets you create standalone returns even if the parcel was not originally shipped through your account, and lets you validate the return request before generating the label to avoid unnecessary charges. The fee mechanics are documented too: customers can be automatically and effortlessly charged a return fee when they create a return via the Return Portal, with payments captured via an external payment service provider, Mollie.

nShift's documentation is the most explicit about carrier-dependent label-free flows. Offer return options across mail, courier pickup, lockers and in-store, with QR-code and label-free flows where your carriers support them, and a parcel shop locator. The Bring/Norway case is a good concrete example rather than a marketing abstraction: if you're using Bring to create Norwegian return shipments, you can create return shipments with a link to a QR code instead of printing labels, and the customer brings the provided QR code to a post office where they can print the label. ShipStation API, by contrast, documents exactly two mechanisms and stops there: set the is_return_label property to true on a normal label call, or create a return label using the label_id of a previously created label. No portal, no QR flow, no paid-returns field in the schema.

Carrier scope: the number that actually matters

Total carrier count is the headline figure every vendor leads with, but it's the wrong number for a returns evaluation. What matters is how many of those carriers actually support returns, and specifically label-free returns. Shippo's return labels, despite broader outbound carrier support, are available for USPS, FedEx, and UPS shipments only. That's the gap you design around: don't assume return-label carrier coverage equals outbound carrier coverage anywhere, because the docs we checked never state that equivalence for any of the nine platforms.

On raw network size, Cargoson publishes the largest figure of the group, though it's not really comparable to the others: Cargoson has built 2,000+ carrier integrations including DHL, FedEx, UPS, DSV, DB Schenker, Bring, DPD, Omniva, Venipak, and many more, spanning freight modes that none of the parcel-first platforms touch. nShift's own figures put it at over 1,000 carriers worldwide. EasyPost is documented elsewhere as sitting around 100+ carriers, Western-weighted. ClickPost's own comparison pages are inconsistent with each other: one lists its carrier depth at 500+ carriers, another table on a different ClickPost page claims 600+. That inconsistency is itself the point of this exercise: marketing pages drift, API references don't.

Where the API stops and a portal begins

If the RFP says "returns API," ask immediately whether that means one label call or a full consumer-facing flow with refund webhooks. Sendcloud and nShift document both ends as distinct, named capabilities you can mix and match. EasyPost documents the label call and is explicit that the portal is somebody else's product: it puts labels behind the same developer portal and authentication scheme as its tracking and returns APIs, but the actual customer journey for returns, refunds, and warranty claims is built through that layered portal structure rather than a single endpoint. Shippo documents the API and web app for merchants, but nothing we found describes a branded, shopper-facing return initiation flow comparable to Sendcloud's or nShift's portal.

• If you only need a label object back from a POST call, Shippo, EasyPost, and ShipStation API all satisfy that with documented endpoints.
• If you need the shopper to choose a reason, a refund method, and a drop-off point without your team touching it, only Sendcloud and nShift document a dedicated portal product in their own API references.
• If you need to charge a return fee automatically, Sendcloud documents the mechanism end to end, including the payment processor. nShift documents fee rules by market and order. Nobody else in this set publishes a fee API.
• If your scope includes freight, pallets, or full truckloads alongside parcel returns, Cargoson's carrier network covers that ground, but consumer-facing return portals sit outside its published scope.

What this audit doesn't tell you

None of this measured whether a QR code actually gets honored at a counter, how long a refund webhook takes to fire after a carrier scan, or what happens when a return label request hits a rate limit. Those require a live test harness against sandbox or production credentials, not a documentation read. The natural follow-up: generate the same twenty return labels in each platform's sandbox, log the HTTP status and payload shape for each, and compare field naming conventions, starting with how Shippo's extra.is_return boolean maps against ShipStation's rma_number field. That's a benchmark for another month.

Where this leaves you

Shortlist Sendcloud or nShift if the requirement is a full portal with fee logic. Shortlist Shippo, EasyPost, or ShipStation API if you only need a label-generation endpoint and plan to build or buy the customer-facing layer separately. Treat ClickPost and AfterShip claims about returns depth as marketing until you can get hands on their actual API reference, since neither publishes the kind of granular returns endpoint documentation the others do. And if your return volume is a rounding error next to freight and pallet shipments, Cargoson's carrier breadth is worth knowing about even though retail-style QR returns aren't part of its published scope. Pull the actual docs before you write the integration ticket. That's the whole lesson here.