Starting in October 2026, third-party apps will no longer be able to connect to Microsoft Exchange Online using the APIs. Microsoft is ending support and is already trying to attract developers to Graph.

Microsoft will stop the Exchange Web Services API for external parties on October 1, 2026. The software giant is already announcing this via a blog, so no one can say they weren’t warned in time. App developers could use the API to connect their applications to Exchange. For example, mail and calendar clients used it to transfer contacts and appointments. Starting October 1, 2026, Exchange will block all requests from external applications.

Microsoft does not give a clear reason for phasing out the Exchange Web Services service. The SDKs for Java and .Net are also being discontinued. Microsoft promises that the changes will not affect Outlook, Teams and other 365 applications connected to Exchange.

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Actually, Microsoft had been preparing us for this announcement for years. In 2018 it was already announced that no new functionality would be added. A first step to stopping the API. The API remains active until the end of its life.

However, developers are urged to move now to the Graph API, which takes over the functionality of Exchange Web Services. Microsoft will expand Graph to eventually make EWS completely obsolete. The blog mentions the following high-demand features without specifying when they will be introduced to Graph:

• Access to the archive
• Access to public folders
• Exchange Online Management
• Configuration of folders