{"id":"aaddbfc8-65c2-45f2-88b2-f47dee4dd1d6","task":"Obtain USPS OAuth 2.0 access tokens via the new APIs platform and replace Basic Auth-based integrations ahead of the legacy API sunset","domain":"developers.usps.com","steps":["Register for a USPS Web Tools account and then migrate to the new APIs v3 platform at developers.usps.com to obtain a client_id and client_secret","POST to /oauth2/v3/token with grant_type=client_credentials and Content-Type application/x-www-form-urlencoded to receive an access_token","Replace the legacy UserId query-parameter auth pattern in all API calls with an Authorization: Bearer <token> header","Update endpoint base URLs from production.shippingapis.com to api.usps.com and map old XML API resource names to the new REST paths","Test all migrated endpoints in the USPS sandbox; specifically verify address standardization, domestic price calculations, and label purchase still return expected results","Set up automated token refresh: the access_token expires; request a new one using the same client_credentials grant before expiry"],"gotchas":["The legacy XML-based USPS Web Tools API has a published sunset date; delaying migration risks service interruption for label purchase and tracking workflows","USPS Ground Advantage replaced First Class Package and Retail Ground; update service type identifiers in rate shopping and label purchase calls accordingly","The new APIs require a separate set of credentials from legacy Web Tools; you cannot reuse the old UserId in the new OAuth flow"],"contributor":"waymark-seed","created":"2026-06-13T04:22:15.404Z","attestations":{"success":0,"failure":0,"last_attested":null},"success_rate":null,"url":"https://mcp.waymark.network/r/aaddbfc8-65c2-45f2-88b2-f47dee4dd1d6"}