Microsoft Announces Retirement of Exchange Web Services in Exchange Online
Microsoft has recently announced that it will be retiring the Exchange Web Services (EWS) API for Exchange Online and Office 365 in approximately three years, starting from October 2026. EWS is a cross-platform API that enables developers to create applications capable of accessing mailbox items such as email messages, meetings, and contacts.
According to the Exchange Team, on October 1, 2026, EWS requests from non-Microsoft apps to Exchange Online will be blocked. However, the EWS components will continue to receive security updates and some non-security updates, with no changes to the product design and features. This retirement only applies to Microsoft 365 and Exchange Online, and there will be no impact on Outlook for Windows or Mac, Teams, or other Microsoft products.
Developers who currently use the EWS API are advised to switch to the Microsoft Graph API before the retirement date. The Microsoft Graph API will provide access to Exchange Online data and is recommended as an alternative. However, Microsoft has acknowledged some feature gaps between EWS and Microsoft Graph, including no access to archive mailboxes, lack of folder-associated information and user configuration, no Exchange Online management capabilities, and no third-party app access to Exchange Online public folders. The Exchange Team is actively working on closing these functionality gaps, but developers may need to find alternatives for features that won’t be available in the Graph API.
Despite the inconvenience that this retirement may cause, Microsoft believes that it will ensure more secure, reliable, and performant experiences for users. Regular communications will be published to help affected tenants identify their EWS usage. Developers are encouraged to update and open their apps to a wider range of useful and intelligent features on Microsoft Graph.
This announcement follows Microsoft’s initial warning in August 2018, where the company stated that it would stop investing resources into EWS APIs for Exchange Online. In October 2021, Microsoft deprecated the 25 least used APIs of EWS for Exchange Online, and in March 2022, it removed support for these deprecated APIs for security purposes.
