USPS — your CRID,
your contract, your rates.
USPS direct is bring-your-own — register a Developer app at developers.usps.com, paste your Consumer Key + Secret into /carriers, and ship at your account's pricing. No relayed-rate markup, no per-label aggregator fee. Prefer the easier path? Use /easypost — same USPS, no Developer-app setup, slight per-label fee.
USPS Domestic + International, end to end.
Once your Consumer Key + Secret are pasted, every USPS product flows through Shipnest — rates, labels, tracking, address validation, scan forms.
Ground Advantage, Priority Mail, Priority Mail Express, Parcel Select, USPS Connect, Library Mail — all quoted in parallel against the rest of your connected carriers. Pick cheapest, fastest, or your default.
USPS International (First-Class Package Service, Priority Mail International) gets per-line customs declarations from your product catalog. EORI / IOSS / VAT auto-stamped on EU lanes where applicable.
USPS Addresses 3.1 runs before every US label buy — wrong addresses caught before the carrier rejects. 'Apply suggestion' takes the normalized version into the order in one click.
Labels are billed to your CRID under your USPS Business Customer Account. No operator-side relay markup, no per-label aggregator fee — just whatever USPS charges your account directly.
USPS direct doesn't expose SCAN forms via the public Developer API. If you ship ≥25 USPS parcels/day, connect EasyPost too — we generate the SCAN form there, you hand it to your driver instead of the carrier scanning every label.
USPS doesn't expose a clean push webhook API, so we poll Tracking 3.0 every 30 minutes. Delivery scans land on the dashboard, the notification bell, and trigger any rules you've set with SHIPMENT_DELIVERED.
USPS Developer app + paste + ship.
- 1Register at developers.usps.com
Sign in with your USPS Business Customer Gateway account, create a new app, subscribe to Prices + Labels + Tracking + Addresses APIs. Takes ~5 minutes; instant approval for the standard set.
- 2Paste Consumer Key + Secret
/carriers → Connect USPS → paste both values + your CRID. We test the connection with a real rate request before saving, so you know the credentials work the second they're stored.
- 3Quote + buy
Every order quotes USPS alongside whatever else you have connected. Buy any service from Ground Advantage to Priority Express; PDF or PrintNode-direct to your label printer.
- 4Add EasyPost if you want SCAN forms
Direct USPS doesn't expose SCAN forms. If you're past the ≥25 parcels/day threshold and your driver wants ONE barcode scan, connect EasyPost alongside — the SCAN form generates there, your labels still post to your USPS account.
Best for US-domestic operations that own their USPS account.
If you already have a Business Customer Gateway account and a CRID, direct USPS through Shipnest is the most cost-effective path — no relay fee, no aggregator margin. If you don't have a USPS Developer app set up and don't want to register one, EasyPost is the simpler alternative — same USPS underneath, slight per-label fee, zero setup.
- BYO posture — Shipnest holds zero financial exposure on your USPS shipments. You pay USPS via your CRID; we charge for the platform layer only.
- Per-tenant credentials encrypted at rest with AES-256-GCM keyed by AUTH_SECRET. Decrypted only at the moment of an outbound API call.
- Multi-piece USPS shipments fan out via parallel /labels/v3/label calls; tracking is keyed per-piece so the buyer sees every box.
Ship USPS without writing API code.
Register a USPS Developer app, paste your Consumer Key + Secret, and you're quoting and printing in under 10 minutes. Or use /easypost if you don't want to register a Developer app at all.