Overview
Exchange Web Services (EWS) and Microsoft Graph are APIs that applications use to access Microsoft 365 data, especially Exchange Online mailboxes. EWS represents Microsoft’s older Exchange integration model, while Microsoft Graph is the modern, unified API for Microsoft 365.
Quick difference:
EWS is an Exchange-specific API focused on mailbox data only (mail, calendar, contacts, tasks) and uses SOAP/XML.
Microsoft Graph is Microsoft’s modern, REST/JSON API that can access Exchange Online plus other Microsoft 365 services (like Teams, SharePoint, OneDrive, and Entra ID) through a single endpoint.
What is EWS?
Exchange Web Services (EWS) is a legacy API designed specifically for Exchange mailbox access.
Key characteristics
Protocol: SOAP (XML over HTTP)
Scope: Mailbox-only (email, calendar, contacts, tasks)
-
Common legacy uses:
Email archiving
Calendar integrations
CRM sync (email/calendar)
Migration and mailbox tooling
Limitation: EWS is Exchange-specific and does not provide access to broader Microsoft 365 services (Teams, SharePoint, OneDrive, etc.).
What is Microsoft Graph?
Microsoft Graph is Microsoft’s modern API platform that provides a single REST endpoint to access Microsoft 365 services.
Key characteristics
Protocol: REST (JSON)
Authentication: OAuth 2.0 / Microsoft Entra ID (Azure AD)
-
Scope: Exchange Online plus other services like:
Teams
SharePoint
OneDrive
Entra ID (Azure AD)
Key differences
| Category | EWS | Microsoft Graph |
|---|---|---|
| API style | SOAP / XML | REST / JSON |
| Scope | Exchange mailbox only | Microsoft 365-wide |
| Authentication | Legacy ecosystem; modern auth possible but not preferred | OAuth-first with scoped permissions |
| Microsoft direction | Legacy / being retired in Exchange Online | Recommended for new development |
Why Microsoft is moving away from EWS
Microsoft has shifted its development focus toward Microsoft Graph and recommends it for all new integrations. This shift is driven by API architecture, security, and long-term platform strategy.
Microsoft is standardizing on Microsoft Graph because it:
Uses modern REST/JSON patterns (lighter and more common for development)
Provides a single API across Microsoft 365 services
Supports granular permissions and stronger security governance
Aligns with Microsoft’s long-term platform strategy
Modern API design
EWS uses SOAP/XML, which is heavier and less common in modern development. Microsoft Graph uses REST/JSON, which is generally simpler to implement, debug, and maintain.
Unified platform
EWS is limited to Exchange mailbox data. Microsoft Graph provides a single endpoint that can access multiple Microsoft 365 services (Exchange Online plus services like Teams, SharePoint, OneDrive, and Entra ID), enabling cross-workload integrations.
Improved security model
Graph is built around OAuth 2.0 with scoped permissions in Microsoft Entra ID (Azure AD), supporting more granular access control and improved governance/auditing compared to many legacy integration patterns.
Long-term platform direction
Microsoft is consolidating its developer ecosystem around Microsoft Graph. As a result, EWS is considered legacy and is not recommended for new development (and is being retired for Exchange Online).
Important timeline (Exchange Online)
EWS in Exchange Online is scheduled to be disabled starting October 2026.
Basic authentication for Exchange Online is already retired, and modern OAuth is required.
Recommendation
New integrations: Use Microsoft Graph
Existing EWS integrations: Plan migration to Graph before EWS is disabled in Exchange Online.