- Microsoft has announced the retirement of the Exchange Web Services API, with EWS requests from non-Microsoft applications to Exchange Online set to be blocked starting in October 2026.
- Developers are encouraged to transition to the Microsoft Graph API as an alternative to EWS, although some important features may be missing in the new API.
- The retirement of EWS only applies to Microsoft 365 and Exchange Online, while it will continue to be supported for Exchange Servers, ensuring continuity for existing on-premises environments.
Microsoft has recently sent ripples through the developer community with its announcement of the retirement of the Exchange Web Services API. The company will begin blocking EWS requests from non-Microsoft applications to Exchange Online starting in October 2026.
Exchange Web Services (EWS) is a cross-platform managed API that allows developers to build custom applications that can access data from Microsoft Exchange Server. It allows developers to perform various tasks such as managing appointments, sending and receiving emails, accessing mailbox data, and more. The API enables apps to access these resources from Exchange Online and on-premises versions of Exchange.
In 2018, Microsoft announced that it would stop investing resources into EWS APIs for Exchange Online. The company further demonstrated its commitment to bolstering security for enterprise customers by deprecating 25 less-utilized APIs in March 2022. Now, Microsoft is planning to shut down Exchange Web Services on October 1, 2026.
Microsoft confirmed that the retirement of EWS only applies to Microsoft 365 and Exchange Online. As Graph API is unavailable for on-premises environments, EWS will continue to be supported for Exchange Servers. Microsoft also assured that Teams, Outlook for Windows, and other Microsoft 365 apps can keep using EWS to read data from Exchange Online.
“While the EWS components of the service will continue to receive security updates and certain non-security updates, product design and features will remain unchanged. This change also applies to the EWS SDKs for Java and .NET, as well. Despite today’s announcement, EWS is still available and supported for use in production environments,” the Exchange team explained.
Microsoft has advised developers to switch from EWS API to Microsoft Graph API instead. However, the company acknowledged that it lacks some important features such as access to archive mailboxes, Exchange Online management capabilities, and folder associated information/user configuration. Moreover, Microsoft Graph API doesn’t offer third-party app access to Exchange Online public folders.