Setting Up Carriers
Connecting USPS, UPS, FedEx and the rest, what each account needs, and why your rates may look higher than expected.
Settings, Shipping, Carriers. Connecting a carrier lets the shop ask them for a real price at checkout instead of using your own table.
Which Carriers
USPS, UPS, FedEx, Canada Post, Australia Post and DHL Express are supported directly. Each needs an account with that carrier and credentials from their developer or business portal.
What Connecting Involves
Every carrier is slightly different, but the shape is the same: create an account with them, generate API credentials in their portal, and paste them here.
Expect to supply your account number as well as keys, because that is what ties a quote to your negotiated pricing rather than to published rates.
Published rates are not your rates
A carrier quotes retail prices by default. Getting your negotiated pricing usually requires the account number to be present and, with some carriers, a specific flag set on the account at their end. If your quotes look much higher than what you actually pay, this is almost always why, and it is fixed at the carrier rather than here.
Services
Each carrier offers several services: ground, express, priority, international. Enable the ones you actually use.
Every enabled service is offered to the shopper as a separate choice, so enabling all of them produces a checkout with a dozen options and a confused customer. Three is usually plenty.
Rate Types
Some carriers distinguish between retail, commercial and negotiated pricing. The setting that controls which you are quoted is per carrier, and getting it wrong gives you quotes that are consistently too high or, occasionally, too low.
Test with a real address and compare against what the carrier's own website quotes for the same parcel. A persistent gap means the rate type rather than the shop.
Packaging
Carriers price by size as well as weight, and some apply dimensional weight, where a large light parcel is charged as if it were heavy.
Where you can define package sizes, do. A shop that quotes every parcel as a single default box will be wrong on both the small and the large ones.
When Quotes Fail
If a carrier does not answer, the shopper sees your other rates. If there are none, they are told you do not ship there, which is better than a silent zero but still a lost sale.
Keep at least one flat rate alongside live rates for that reason. It costs nothing and it means an outage at the carrier does not close your shop.
Testing
Quote four parcels: a single light item, a heavy one, a large awkward one, and an international destination. Those four cover most of what goes wrong.
Compare each against the carrier's own quote for the same parcel. The point is not that they match to the penny but that they are in the same region. A tenfold difference is a weight or a unit problem, usually grams against ounces.
Weights Matter More Than Anything Here
A live quote is only as good as the weights on your products, and one wrong weight distorts the quote for every basket that product lands in. If you are turning on live rates for the first time, audit your weights first.