Microsoft announced today that the Exchange Web Services (EWS) API for Exchange Online will be shut down in April 2027, after nearly 20 years.

EWS is a cross-platform API for developing apps that can access Exchange mailbox items, such as email messages, meetings, and contacts, retrieved from various sources, including Exchange Online and on-premises editions of Exchange (starting with Exchange Server 2007).

Microsoft will begin blocking Exchange Online EWS by default on October 1, 2026, but administrators can temporarily maintain access via an application allowlist. The final shutdown occurs on April 1, 2027, with no exceptions granted.