Commercial Base pricing (a.k.a. CBP) is a USPS program that offers discounted postage rates to shippers that buy postage online through providers like Stamps.com.
ShipEngine includes a free Stamps.com account with your subscription, so you have access to CBP rates already! CBP rates are better than what you'd get at your local post office, but if you want an even deeper discount, Stamps.com offers Commercial Plus Pricing (a.k.a. CPP) for certain Priority Shipments.
For full CPP rates for one or more services through Stamps.com, they may be available IF you met the appropriate USPS threshold in the previous calendar year (or previous four quarters for Priority Mail Express):
If you think you've met these thresholds, contact Stamps.com to confirm that you qualify and then start the application process with the USPS. You may even get special perks like Cubic pricing, or the ability to ship First Class Packages up to 15.99 ounces.
Please reach out to ShipEngine support if Stamps.com enables CPP rates and/or special perks on their side. We'll flip a switch on our end so that your Stamps.com-approved rates and perks work in ShipEngine!