USPS Integration
USPS commercial pricing on your own account, postage from your EPS balance.
USPS v3 rates, labels and tracking on your own account. Rating needs two credentials; buying labels needs four.
Connector Technical Specs
Integration Overview
How TackQuote connects with USPS
Eliminate manual data entry, prevent shipping or pricing errors, and streamline B2B order execution.
TackQuote speaks USPS APIs v3 directly, authenticating your own consumer key pair over OAuth 2.0 and pricing parcels against your account so rates are USPS commercial pricing rather than an aggregator's marked-up retail. Label postage is drawn from your Enterprise Payment System account, and no per-label aggregator fee applies. One limitation is stated up front because discovering it later is expensive: USPS is the only carrier here where an authenticated request is not enough to buy. Postage needs a payment authorisation, and that call needs your CRID and MID — enrolment identifiers, not secrets — before USPS will mint the token a label request must carry. So the connection reports rating-ready and label-ready as two SEPARATE facts. A seller with a consumer key pair and an EPS account can rate today and will be told plainly that labels additionally need the CRID and MID, rather than being shown one "Connected" badge that implies they can ship. Coverage is US domestic; USPS International is a different product this connection does not speak.
Bi-Directional Sync
Data objects synchronized between systems
Here is exactly how data flows between TackQuote and USPS to maintain complete system alignment.
Carrier Rate & Freight Calculation
Fetch live negotiated parcel and LTL freight rates from USPS directly into quote line items.
Shipping Label & Tracking Sync
Generate shipping labels automatically upon quote acceptance and push USPS tracking numbers to buyers.
Commercial Invoices & Customs
Pass harmonized tariff codes and item weight parameters to USPS for international shipping compliance.
Address & Surcharge Validation
Verify recipient delivery addresses and automatically calculate fuel/residential surcharges before quote sign-off.
Capabilities
What's included in the USPS connector
Built out-of-the-box for enterprise sales teams, distributors, and manufacturers.
Rating And Labelling Reported Separately
Verification tells you whether you can rate and whether you can ship, as two facts. A missing CRID never hides behind a single green "Connected" state.
Commercial Pricing, No Aggregator Fee
Rates are priced against your own USPS account and postage is drawn from your EPS balance. Nothing adds a fee per label on top.
Enrolment IDs Stored As What They Are
CRID and MID are enrolment identifiers rather than secrets, so they are stored under their own names instead of being smuggled into a field labelled "secret".
Testing Environment Supported
USPS's Testing Environment for Mailers issues non-billable labels, so the label path can be exercised before postage is real.
Setup Guide
4 steps to connect USPS
Rate with two credentials, ship with four. The connection tells you which of those you currently have.
Store your consumer key pair and EPS account
Consumer Key, Consumer Secret and your EPS account number are enough to start rating, and belong under Settings → Shipping Carriers.
Add your CRID and MID when you want labels
Both are optional at connect time precisely so a seller who wants rates today is not blocked by an enrolment they may not have. Add them and label purchases can be authorised.
Rate, label, track
Request rates for a domestic parcel, buy a label once the payment authorisation can be minted, and pull tracking on demand with full detail.
Requirements
What you need to get started
Prerequisites for authenticating USPS with your TackQuote tenant.
- A USPS Developer Portal app for the Consumer Key and Consumer Secret
- An Enterprise Payment System (EPS) account number — rates are priced against it and postage is drawn from it
- A CRID and MID enrolled for label printing, required before USPS will authorise postage (rating works without them)
- US domestic destinations — USPS International is not supported on this connection
All integrations included
No per-connector fees, middleware subscriptions, or hidden charges. Connect USPS and all 63+ connectors under your standard TackQuote plan.
FAQ
Frequently asked questions about USPS
Why can I rate but not buy a label?
Because USPS needs a second credential to spend money. A label request must carry a payment-authorisation token, and USPS only mints that token when your CRID and MID are present. Add both and label purchases can be authorised; until then the connection says so explicitly.
Are these USPS commercial rates or retail rates?
Commercial pricing on your own account. Note that a successful authentication proves your app credentials, not your pricing entitlement, so run a rate test to confirm your account is returning commercial rather than retail figures.
Can I ship USPS International through this connection?
No. It is US domestic only. USPS International is a separate product with its own customs requirements, and TackQuote does not speak it — so an international lane is refused rather than mispriced.
Can TackQuote void or refund USPS postage?
No. Void and refund are not implemented on any carrier connection, deliberately: a refund path that half-works is worse than none. Reconcile refunds with USPS directly.
Workflow Ecosystem
Works seamlessly alongside USPS
Combine shipping, ERP, CRM, and payment connectors for end-to-end B2B sales automation.
Ready to connect USPS?
Start your free 14-day TackQuote trial. Connect USPS in under 5 minutes with zero credit card required.