Knowledge Base

Are you are still using USPS WebTools API to retrieve shipping rates? If so, you have until January 25, 2026 to migrate to the new USPS API to prevent service disruptions. The new API uses OAuth 2.0 authentication which is entirely different from the old USPS WebTools API. You will need obtain a set of new credentials from USPS in order to access the new API.

In this guide, we'll show you how to obtain access to the new API from USPS. The OAuth credentials you'll need are the Consumer Key and Consumer Secret.

First, log in to the USPS Developer Portal. If you don't have an account already, you will need to create one. Once you're logged in, click Apps on the top menu bar and then click Add app.

The application name can be anything. We recommend using the name "solvingmaze" for record keeping. Leave the "Callback URL" field empty and tick the "Public Access I" checkbox. Click the "ADD APP" button to submit.

You should now see the app you've created with status set to "Approved".

Click "Edit" to view the app, and then select the "View" tab to view your credentials:

Your USPS OAuth credentials (Consumer Key and Consumer Secret) will be displayed here. Make sure to copy and save them in a secure location.

Once you have your USPS OAuth credentials (Consumer Key and Consumer Secret), you can use SolvingMaze to help you estimate postage by factoring in box sizes and packaging costs. To set up for USPS shipping rates at SolvingMaze, select USPS API for Shipping Rates API in your SolvingMaze menu, and enter your USPS account number and API credentials.

Register for a free 30 day trial account today and see what we can do for you.