What This Integration Does
This integration synchronises calendars, contacts, files, and email-related data between Google Workspace and Microsoft 365 so that teams split across both platforms collaborate without friction. When a meeting is created in Google Calendar, it appears in Outlook. When a contact is added in Microsoft 365, it is available in Google Contacts. Shared files are accessible from either platform’s file browser without manual copying.
The scenario is common: a company uses Google Workspace internally but works with clients, partners, or an acquired team that uses Microsoft 365. Or the business is migrating from one platform to the other and needs both to function seamlessly during the transition. Without integration, the result is missed meetings, outdated contact lists, file version conflicts, and a general sense that half the organisation cannot see what the other half is doing.
The Workflow
The integration connects the Google and Microsoft APIs to maintain near-real-time synchronisation across the productivity functions that matter most.
Calendar sync is bidirectional. Events created in Google Calendar appear in the connected Outlook calendar, and vice versa. Attendees, time zones, recurrence patterns, and conference links are translated between platforms. When an event is updated or cancelled in either system, the change propagates. Free/busy information is shared across platforms, so scheduling a meeting with a colleague on the other system shows their actual availability.
Contact sync keeps address books consistent. Contacts added, updated, or deleted in either platform are reflected in the other. For organisations with a shared company directory, the integration pulls from the primary directory (Google Directory or Azure Active Directory) and populates the other platform, ensuring everyone has access to the same organisational contacts regardless of which email client they use.
File sync handles the most complex translation. Google Docs, Sheets, and Slides do not have direct file equivalents in Microsoft 365 — they are stored as cloud-native formats, not downloadable files. The integration provides cross-platform access by creating links in the other platform’s file browser that open the document in its native editor. For genuine file sharing (Word, Excel, PowerPoint documents and PDFs), files stored in OneDrive or SharePoint are mirrored in Google Drive and vice versa, with version tracking to prevent conflicts.
Email routing and delegation ensures that shared mailboxes, distribution lists, and mail routing rules function across both platforms. A shared support inbox that lives in Microsoft 365 can be accessed by team members on Google Workspace, with replies sent from the correct shared address regardless of which client the team member uses.
Before and After
Before: Teams on Google Workspace and Microsoft 365 experience constant friction. Meeting invitations between platforms arrive as plain text without calendar integration. Files shared between teams require downloading, editing, and re-uploading. Contact information diverges within weeks. The IT team spends hours resolving cross-platform issues that should not exist.
After: Calendars show every meeting regardless of which platform created it. Contacts are consistent across both systems. Files are accessible from either platform without manual transfer. New team members are set up on whichever platform their team uses, and the integration handles the cross-platform connectivity transparently.
Who Needs This
This integration is for organisations where both Google Workspace and Microsoft 365 are in active use — whether by choice, circumstance, or transition. Common scenarios include: companies that acquired a team using a different platform, businesses migrating from one platform to the other, and organisations where specific teams have strong preferences for one platform that the business has decided to accommodate rather than override.
If your team wastes time on cross-platform friction — forwarding calendar invitations, manually syncing contacts, emailing files because sharing does not work across platforms — this integration eliminates that overhead.
How We Build This
We build this using the Google Workspace APIs (Calendar, People, Drive, Gmail) and Microsoft Graph API. Both platforms provide comprehensive APIs with OAuth2 authentication and webhook support for real-time event detection.
The integration middleware handles the data model translation between platforms — Google and Microsoft represent calendar events, contacts, and files differently, and the middleware maps between these structures without data loss. Conflict resolution rules handle the inevitable case where the same record is updated in both platforms simultaneously, using configurable rules about which platform is authoritative for which data type.
Stop Fighting Your Productivity Tools
If your team spans Google Workspace and Microsoft 365 and the disconnect is slowing people down, get in touch to discuss which sync functions would remove the most friction for your organisation.
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Alex
I’m a software developer and CEO of Digital Royalty, helping growing teams scale their SaaS platforms without losing quality, visibility, or control. I focus on building structured, maintainable systems with clear processes, reporting, and accountability. With over a decade of experience across agency and in-house roles, I specialise in delivering long-term, scalable solutions that support complex, evolving products.