Microsoft 365 and Outlook scheduling with booking links

How the Microsoft connection works

You sign in with your Microsoft account and approve the permissions on Microsoft's OAuth consent screen. If your organization requires admin approval for third-party apps, your Microsoft 365 administrator grants it.

Kalendarius then checks free and busy times on the connected calendar through Microsoft Graph. When something changes in Outlook, Microsoft notifies us and your open slots update. We don't store the titles or descriptions of your other events. New bookings show up in Outlook a few moments after the guest confirms.

How to set up scheduling software that integrates with Outlook

1. Create a free account or sign in, then open Calendars in the dashboard.

2. Choose Connect on the Microsoft Outlook card. Sign in with your Microsoft 365 or Outlook.com account and approve the permissions on Microsoft's consent screen. If your organization requires admin approval for third-party apps, ask your administrator to grant it first.

3. Back in Kalendarius, the card shows Active. Open an event type, set its location to Microsoft Teams if each booking should get a Teams link, and share your booking link.

A Teams link for every booking

Set an event type's location to Microsoft Teams and each booking gets its own Teams meeting link, in the Outlook event and in the guest's confirmation email. Other options are Google Meet or Zoho Meeting (also created automatically), a phone call, an address, or a link you paste yourself.

Guests see times in their own time zone, get a calendar file with their confirmation, and receive email reminders 24 hours and 1 hour before.

For IT: single sign-on and audit log on Business

Business costs €17.90 per organizer per month. It adds single sign-on with Microsoft Entra ID and an audit log. A Data Processing Agreement (DPA) for the Business and Enterprise plans is in legal review; contact info@kalendarius.com. Enterprise starts at €9,900 a year.

Single sign-on works only with Microsoft Entra ID. There is no SAML support and no SCIM provisioning.

Collective and round-robin links

On the Team plan (€9.90 per organizer per month, up to 25 organizers) you can create collective links for panels and round-robin links that pass each booking to the free colleague with the fewest bookings on that link. Colleagues who only connect their Outlook calendar so their availability counts don't pay. More on team scheduling.

Microsoft Bookings or a Kalendarius booking link

Microsoft Bookings is included in many Microsoft 365 and Office 365 subscriptions, including Business Basic, Business Standard, Business Premium, E3 and E5, according to Microsoft's Bookings overview (as of October 2026). Its personal version, Bookings with me, also called Personal Bookings, gives a licensed user a booking page for 1:1 meetings that reads their Outlook calendar; shared booking pages cover teams. Microsoft stores Bookings data in Exchange Online, as the Personal Bookings FAQ explains. If your organization already has one of those plans and everyone works in Outlook, Bookings may be all you need.

A Kalendarius booking link fits when you want the booking page and the emails Kalendarius sends to run outside Microsoft 365, or when not everyone uses Outlook. Booking records are stored on Hetzner servers in Germany. On Team, colleagues on Google Calendar or Zoho Calendar can share a collective or round-robin link with Outlook users. A link can require approval, so requests wait until you accept them, and each booking can get its own Teams link. You pay per organizer, not for everyone whose calendar is checked.

Connecting Microsoft 365 doesn't take Microsoft out of the picture: the event Kalendarius writes into your Outlook calendar, with the guest's name, email and notes, is still processed by Microsoft, like any other calendar entry. Outlook also emails the guest an invitation from your mailbox, and a cancellation if the booking is cancelled or rescheduled.

Hosting and what it covers

The Kalendarius application and database run on Hetzner servers in Germany. Your Outlook calendar stays in Microsoft 365, under your Microsoft agreement, and the events we write into it are processed there. As the controller, you still decide the lawful basis, what your booking form asks and how long appointments are kept. Completed appointments are deleted after the retention period you set, up to 365 days on Business. Events already written to Outlook stay there.

Limits worth knowing

Each user connects one Microsoft account, and Kalendarius checks one calendar per connection, so secondary or shared calendars don't block slots. You can connect one Google and one Zoho account alongside it. Kalendarius doesn't book rooms or other resources.