Multi-Tenant SOAP to REST Migration for Carrier Integration: Architecture Patterns That Preserve Tenant Isolation During the 2026 API Transition Wave
Major carriers are abandoning their SOAP-based APIs faster than most engineering teams anticipated. USPS is retiring their Web Tools API platform on January 25, 2026, while FedEx's OAuth authorization migration must be completed by March 31, 2026 - after which SOAP web services will no longer be available