API
Microsoft
Microsoft begins blocking Exchange Web Services (EWS) requests from non-Microsoft apps to Exchange Online; developers must migrate to Microsoft Graph
departs 1 Oct 2026
Quick answers
- Is it true that Microsoft retires Exchange Web Services (EWS) in Exchange Online — blocks requests on October 1, 2026?
- Yes. Microsoft has officially announced it, effective 1 Oct 2026. If your app calls Exchange Web Services (EWS) against Exchange Online or Microsoft 365 mailboxes, Microsoft will start blocking those requests on 1 October 2026.
- When does it take effect?
- 1 Oct 2026. Verified against the vendor's own announcement.
- What should I use instead?
- Microsoft's direction is to move Exchange Online access to Microsoft Graph, which it has recommended since it froze EWS feature work in 2018.
What this means for you
If your app calls Exchange Web Services (EWS) against Exchange Online or Microsoft 365 mailboxes, Microsoft will start blocking those requests on 1 October 2026. This hits any non-Microsoft app using the EWS Managed API or the EWS SDKs for .NET and Java to read mail, calendars, contacts, or folders in Exchange Online — a common pattern in backup tools, migration utilities, signature managers, CRM connectors, and in-house line-of-business integrations. The block is scoped: it applies only to Microsoft 365 and Exchange Online (all environments). EWS on Exchange Server on-premises is not affected and stays fully supported, so on-prem-only integrations do not need to move.
Where to go
Microsoft's direction is to move Exchange Online access to Microsoft Graph, which it has recommended since it froze EWS feature work in 2018. Inventory every app and script that calls EWS against Exchange Online, then re-implement those calls against the equivalent Microsoft Graph endpoints and permissions. Microsoft acknowledges specific feature gaps that still lack a Graph equivalent — notably access to archive mailboxes and folder-associated information / user configuration — and says it will publish updated timelines for them; if your workload depends on one of those, confirm Graph coverage before committing to a cutover date. Because EWS keeps working until 1 October 2026, migrate and validate app-by-app rather than in a single switchover.
- Microsoft Graph — Microsoft's recommended API for programmatic access to Exchange Online mail, calendar, contacts, and folders
Microsoft is retiring Exchange Web Services (EWS) for Exchange Online. In its Exchange Team announcement, Microsoft says that on 1 October 2026 it “will start blocking EWS requests” from non-Microsoft apps to Exchange Online, and urges developers to move to Microsoft Graph.
This closes a path Microsoft signalled long ago: it stopped making feature updates to EWS in 2018 and told developers then to move to Graph. EWS remains available and supported for production use right up to the date — but after it, third-party apps calling EWS against Microsoft 365 mailboxes will be turned away.
Who this affects
Any non-Microsoft app that talks to Exchange Online or Microsoft 365 mailboxes over EWS — directly, through the EWS Managed API, or via the EWS SDKs for .NET and Java, which Microsoft says are covered by the same change. In practice that is a long tail of software: mailbox backup and archiving tools, tenant-to-tenant migration utilities, email-signature managers, calendar and CRM connectors, and the in-house line-of-business scripts that quietly move mail and calendar data around a tenant.
The scope is important. Microsoft is explicit that the retirement applies only to Microsoft 365 and Exchange Online (all environments) and that there are no changes to EWS in Exchange Server — EWS stays fully supported for on-premises mailboxes. If your integration only ever talks to on-prem Exchange, this change does not touch it.
What to do
Microsoft’s recommended action is to migrate Exchange Online workloads from EWS to Microsoft Graph.
- Inventory every app, service, and script that calls EWS against Exchange Online — including anything using the EWS Managed API or the .NET / Java EWS SDKs.
- Map each EWS operation to its Microsoft Graph equivalent and the Graph permissions it needs.
- Check the known gaps first. Microsoft acknowledges that some capabilities still lack a Graph equivalent — it names archive-mailbox access and folder-associated information / user configuration — and says it will share updated timelines. If your workload relies on one of these, confirm Graph support before setting a cutover date.
- Migrate app-by-app. EWS keeps working until 1 October 2026, so you can move and validate one integration at a time rather than in a single big-bang switch.
Entry changelog
- — last reviewed.
- — Entry created from Microsoft's Exchange Team blog announcing the retirement of EWS in Exchange Online. The 1 October 2026 start date for blocking EWS requests, the non-Microsoft-app scope, the Exchange-Online-only scope (no change to Exchange Server on-premises), the inclusion of the EWS SDKs for .NET and Java, and the Microsoft Graph migration path are all taken directly from Microsoft's announcement. No detect: fingerprint added on purpose — EWS code cannot reveal whether it targets Exchange Online (affected) or Exchange Server on-premises (not affected), so any fingerprint would misfire on on-prem users.
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