Configure Calendar interoperability with Microsoft Office 365 using the Microsoft Graph API
What’s changing Beginning today, Admins can use the Microsoft Graph API to enable Calendar interoperability with Microsoft Office 365. The Graph API will replace the existing Exchange Web Services (EWS) API, which will no longer be supported by Microsoft beginning October 1, 2026 – we recommend that admins update their interop configuration to Graph API as soon as possible. Admins can configure interoperability via the Graph API in the Admin console by going to Apps > Google Workspace > Calendar > Calendar Interop Management > Exchange availability in Calendar > Allow Google Calendar to display Exchange user availability. The user interface has also been streamlined and admins can easily select an endpoint from a drop down list, and enter other details like the specific Microsoft domain that should be connected to Calendar, and specify role accounts for user availability and resource booking. Quickly select your endpoint type from the new drop down listEnter additional details, like the Microsoft domain you want to connect to and role accounts.We’ve also made additional updates to improve the overall admin experience, including additional user interface updates and troubleshooting — keep reading for more information.Who’s impactedAdminsWhy it’s importantThese updates will ensure calendar interoperability continues after support for EWS ends and improve the overall experience for configuring and managing interoperability for admins. Additionally, the Graph API allows admins to grant access to Exchange calendar data only, ensuring access isn’t too broadly scoped. Additional detailsAlso included in this update are the following improvements:Admins can use the same role accounts for user availability and resource booking when configuring their Graph API interop setup.We’re making it easier for admins to troubleshoot errors encountered while setting up interoperability. Admins can now see detailed information each step of the way which will help them work through potential issues in the setup configuration.The overall Admin user interface has been streamlined as well. Admins can define which domains are supported by which endpoint, and this information is neatly listed in a table. This makes it easily scannable and actionable, and helps avoid unnecessary queries trying to get the availability of users who are not part of a domain covered by the interop setup.Apps > Google Workspace > Settings for Calendar > Calendar Interop managementIf admins select EWS, or have existing endpoints set up using EWS, they will see a reminder banner that EWS will no longer be supported by Microsoft and to use the Graph API instead.Getting startedAdmins: As the Exchange Web Services endpoint type will no longer be supported beginning October 1, 2026, we recommend updating your interop configuration to Graph API as soon as possible. Visit the Help Center to learn more about Calendar interoperability, and specifically allowing Calendar users to see Exchange availability.End users: There is no end user action required.Rollout paceRapid Release and Scheduled Release domains: Gradual rollout (up to 15 days for feature visibility) starting on May 28, 2025AvailabilityAvailable for Google Workspace:Business Starter, Standard, and PlusEnterprise Starter, Standard, and PlusEducation Fundamentals, Standard, and PlusFrontline and Frontline PlusNonprofitsResourcesGoogle Workspace Admin Help: About Calendar interopGoogle Workspace Admin Help: Allow Calendar users to see Exchange availability
What’s changing
Beginning today, Admins can use the Microsoft Graph API to enable Calendar interoperability with Microsoft Office 365. The Graph API will replace the existing Exchange Web Services (EWS) API, which will no longer be supported by Microsoft beginning October 1, 2026 – we recommend that admins update their interop configuration to Graph API as soon as possible.
Admins can configure interoperability via the Graph API in the Admin console by going to Apps > Google Workspace > Calendar > Calendar Interop Management > Exchange availability in Calendar > Allow Google Calendar to display Exchange user availability. The user interface has also been streamlined and admins can easily select an endpoint from a drop down list, and enter other details like the specific Microsoft domain that should be connected to Calendar, and specify role accounts for user availability and resource booking.
Quickly select your endpoint type from the new drop down list
Enter additional details, like the Microsoft domain you want to connect to and role accounts.
We’ve also made additional updates to improve the overall admin experience, including additional user interface updates and troubleshooting — keep reading for more information.
Who’s impacted
Admins
Why it’s important
These updates will ensure calendar interoperability continues after support for EWS ends and improve the overall experience for configuring and managing interoperability for admins. Additionally, the Graph API allows admins to grant access to Exchange calendar data only, ensuring access isn’t too broadly scoped.
Additional details
- Also included in this update are the following improvements:
- Admins can use the same role accounts for user availability and resource booking when configuring their Graph API interop setup.
- We’re making it easier for admins to troubleshoot errors encountered while setting up interoperability. Admins can now see detailed information each step of the way which will help them work through potential issues in the setup configuration.
- The overall Admin user interface has been streamlined as well. Admins can define which domains are supported by which endpoint, and this information is neatly listed in a table. This makes it easily scannable and actionable, and helps avoid unnecessary queries trying to get the availability of users who are not part of a domain covered by the interop setup.
Apps > Google Workspace > Settings for Calendar > Calendar Interop management
- If admins select EWS, or have existing endpoints set up using EWS, they will see a reminder banner that EWS will no longer be supported by Microsoft and to use the Graph API instead.
Getting started
- Admins: As the Exchange Web Services endpoint type will no longer be supported beginning October 1, 2026, we recommend updating your interop configuration to Graph API as soon as possible. Visit the Help Center to learn more about Calendar interoperability, and specifically allowing Calendar users to see Exchange availability.
- End users: There is no end user action required.
Rollout pace
- Rapid Release and Scheduled Release domains: Gradual rollout (up to 15 days for feature visibility) starting on May 28, 2025
Availability
Available for Google Workspace:
- Business Starter, Standard, and Plus
- Enterprise Starter, Standard, and Plus
- Education Fundamentals, Standard, and Plus
- Frontline and Frontline Plus
- Nonprofits
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