Microsoft Announces End of Support for Exchange Online EWS in April 2027

Microsoft to Shut Down Exchange Web Services API in 2027

Microsoft recently announced the upcoming shutdown of the Exchange Web Services (EWS) API for Exchange Online, marking the end of a nearly 20-year run for the API. EWS, a versatile API used for developing apps that interact with Exchange mailbox items, will cease operations in April 2027.

EWS has been a crucial cross-platform API for accessing email messages, meetings, and contacts from Exchange Online and on-premises Exchange editions since Exchange Server 2007. However, Microsoft will start blocking Exchange Online EWS by default on October 1, 2026. Administrators can temporarily maintain access through an application allowlist, but this access will be completely terminated on April 1, 2027.

Administrators have until the end of August 2026 to create allow lists and configure settings to avoid automatic blocking in October. Microsoft will populate allow lists for organizations without their own lists starting in September 2026 based on usage patterns.

Leading up to the final shutdown, Microsoft may conduct temporary tests to identify hidden dependencies on EWS and inform IT admins through monthly notifications in the Message Center, providing reminders and usage summaries specific to each tenant.

It’s important to note that the retirement of EWS only affects Microsoft 365 and Exchange Online environments. EWS will continue to be operational in on-premises Exchange Server installations.

The Exchange Team stated, “EWS was built nearly 20 years ago, and while it served the ecosystem well, it no longer aligns with today’s security, scale, or reliability requirements.”

Developers currently using the EWS API are advised to transition to the Microsoft Graph API as EWS approaches retirement. The Microsoft Graph API offers almost complete feature parity with EWS for most scenarios.

While EWS is being phased out for Exchange Online, it will remain functional for on-premises Exchange Server installations. Hybrid scenarios will vary based on how apps access data, with on-prem mailboxes continuing to use EWS and cloud mailboxes transitioning to Graph.

Microsoft’s decision to retire EWS follows a 2018 warning that EWS would no longer receive functionality updates. In October 2021, Microsoft deprecated the 25 least-used EWS APIs for Exchange Online, removing support for them in March 2022 for security reasons.

Discover how to streamline your IT infrastructure with automated workflows. Download the Tines guide to reduce manual delays and improve reliability through automation.

Get the guide