Logistics & Supply Chain · Integration
USPS
Add USPS to your product for your customers, and give your AI agents governed access to it.
USPS gives you four things worth embedding and they separate cleanly. Address validation standardises what somebody typed and returns the ZIP+4 the Postal Service will actually route on. Pricing quotes a service against the dimensions and weight you pass. Labels create the shipment and hand back the printable artefact. Tracking returns scan events against a tracking number. The awkward parts are practical rather than architectural: buying a label is the one call in the set that spends money, a standardised address sometimes comes back in a form the person who typed it does not recognise, and a rate is only as honest as the dimensions behind it. Each customer supplies their own USPS credentials, so postage is bought on their account rather than yours. Those credentials sit with fastn, scoped to the tenant they belong to, and API revisions land here instead of in your backlog.
In your product
Embedded for your customers. Per-tenant auth, no per-customer code, maintained by fastn.
Let each customer connect their own USPS account so labels are bought against their postage rather than yours.
Standardise an address at the moment somebody types it, and store the ZIP+4 the Postal Service returns instead of the one they guessed.
Quote a domestic rate from real dimensions and weight before your product commits to a shipping price.
Read tracking scans against a number your product already holds, so delivery status appears without anybody visiting a tracking page.
For your AI agents
Governed, audited access for the agents you build, through the MCP server.
An agent checks where a parcel was last scanned and what the scan said, reading only that customer's account.
An agent validates and corrects an address before a label is bought, so a return does not begin with a typo.
An agent quotes two services against each other and explains the difference, without buying either until somebody approves it.
Example prompt
Where was this USPS tracking number last scanned, and is the delivery still on schedule?
Set up USPS in 4 steps
- 01Enable the USPS connector in your fastn dashboard.
- 02Have each customer supply their own USPS credentials so postage and labels are charged to their account.
- 03Decide which of address validation, pricing, label creation and tracking your product needs, and treat label creation as the one call that spends money.
- 04Call it from your product and expose the same connection to your agents through the MCP gateway.
Why teams use the USPS integration
What you get by embedding it with fastn instead of building it yourself.
- Ship a USPS integration without building it. Your customers connect their own USPS account inside your product and work their shipments, tracking events and orders there, with no per-customer code on your side.
- Handle the part that actually costs time: tracking data arrives from many carriers in inconsistent formats and at unpredictable times. fastn owns the auth, token refresh, rate limits, pagination and breaking-change fixes, so a USPS update is not your on-call problem.
- One integration serves your product and your agents. The same governed USPS connection powers in-product features and gives AI agents scoped, audited access, so you keep physical movement and stock visible inside your product without wiring it twice.
Used by these teams
Compare with
FedEx
EasyPostWorks well with
ShopifyOften used alongside
Tools the same teams tend to run next to USPS, across other categories.
NetSuite
Stripe
QuickBooks
BigCommerceUSPS integration FAQ
How do I add a USPS integration to my product?
Enable the USPS connector in your fastn dashboard, then let each customer authenticate their own USPS account. fastn handles the OAuth flow, token storage and refresh per tenant, so there is no USPS client code in your app and no per-customer branch in your codebase. Setup is 4 steps.
Do my customers each connect their own USPS account?
Yes. Every connection is scoped to the individual customer, so each authorises their own USPS account and only ever sees their own shipments, tracking events and orders. That per-tenant isolation is the point of an embedded integration: you support the long tail of customer setups without maintaining an integration per customer.
Can AI agents use this USPS integration?
Yes. The same connection is exposed to your agents through the fastn MCP gateway, with permissions scoped per tenant and every call audited. An agent checks where a parcel was last scanned and what the scan said, reading only that customer's account.
Who maintains the USPS integration?
fastn does. When USPS changes an endpoint, deprecates a field or alters its auth, the fix lands in the connector rather than in your backlog, and your customers' connections keep working.
Can I track shipments from USPS inside my product?
Yes. Shipment and tracking events are read per customer and can trigger your workflows, so status changes surface in your product instead of your users checking a carrier site.
What does my product get back from USPS as things move?
Whatever USPS actually holds. Where it moves goods, that is shipment and tracking events, read per customer and delivered as they land. Where it holds stock, levels can be read on demand or kept in step through events, so your product is not deciding on a stale count. Where it carries orders and documents between trading partners, it is the acknowledgement, ship notice or status change that says what moved.
What can I build with the USPS integration?
A common starting point: let each customer connect their own USPS account so labels are bought against their postage rather than yours. Teams also use it for the other use cases listed above, and expose it to agents for governed reads and writes.
How much does the USPS integration cost?
It is included. Pricing is based on connected accounts, not on how many connectors you enable, so adding USPS does not change your per-connector cost. You can start free with 3 connected accounts.
Add USPS to your product
Start free with 3 connected accounts. No sales call required, and no per-customer integration code.