Sync your app with the Office 365 API

Build great scheduling features for your Office 365 users with the Cronofy Calendar API

Get started

One API, all calendars

Build better business software

Microsoft Office is the world’s most popular software suite. It’s used by businesses all over the world to create documents, send and receive emails, and organize meetings.

Companies used to have to host this on their own server using Microsoft Exchange, but Office 365 offers a cloud-based solution that means they don’t need to anymore.

While this can make things more efficient for businesses, for companies that build software that connects to these services, it complicates things.

Code for one API, work with every calendar

The Cronofy API works with all the major calendar services.

Instead of building individual integrations with Office 365, Exchange,, iCloud, and Google Calendar, you work with just one API that’s compatible with them all.

Office 365 calendar API

Real-time Calendar Sync

Avoid synchronization issues

Traditionally, when a calendar event is created and sent to someone using a different calendar service, two different versions of the event exist on two different platforms.

Problems can then occur if something is changed, as changes don’t always sync across. This could result in employees missing out on crucial information about a client meeting.

It doesn’t matter if your company uses Office 365 and your client uses Google Calendar. Every time an update is made to the calendar appointment, it syncs across in real-time. There’s no delayed reaction or risk of someone missing something important. Even if they don’t use Cronofy themselves.

Create secure connections

Much like other calendar APIs, Office 365 offers an all-or-nothing perspective when it comes to dealing with customers’ data.

This means that that you can either see all of the details of users’ calendar events, or none of them. When users’ privacy is important to you, this can make building connections even more complex.

Cronofy gives you the option to only access users’ free/busy data. You don’t need to worry about dealing with private customer information, and users don’t need to share private calendar details with anyone.

Free trial

Full calendar sync with Cronofy

Sync your software to iCloud, Google Calendar, Office 365, and even Microsoft Exchange calendars

Create your account

Cronofy also offers...


Global environment compatibility

Cronofy has been built for easy integrations across all programming languages, frameworks, and environments, not just those specific to Microsoft and Windows.


Unified calendar access

Cronofy not only provides you with the Office 365 Calendar API, but also the calendar APIs for, Exchange, iCloud and Google Calendar. Code for one API, integrate with all of them.


Better user experience

Cronofy ensures easier development and better UX out of the box. Offer your users integration with the calendar service of their choice without extra work on your part.


Guaranteed active development

Our calendar API benefits from new releases and changes rolled out on a regular basis. If you’re the early adopter type, we also have a separate Alpha channel for you to test upcoming features.


Calendars everyone can rely on

We’ve resolved the standard synchronization problems so common with calendar development work so that you and your users can rely on precise availability and up-to-the-minute booking information.


Practical API documentation

The Cronofy API docs are all you need to get full access to five different calendar APIs. Crafted by our own in-house developers, our API documentation is a concise resource that contains everything you need for robust calendar integration.


99.95% uptime SLA

We guarantee a minimum uptime of 99.95% so you can rest assured that you’re offering users a highly dependable service 24/7.


Data modeling

Privacy is one of our biggest priorities. Data is handled securely and as a developer you only access required information, unlike the standard Office 365 API.


Dedicated support

Our team is on hand to help with any questions you have about Cronofy, integrations, documentation, and so on.

Personio is building an innovative HR management and recruiting solution for HR departments, managers and employees. Real-time calendar sync is crucial to ensuring it fits seamlessly into both their working and personal lives.

Hanno Renner
Co-founder & CEO - Personio

Explore our customer stories

Cronofy/Office 365 FAQs

How do I use the Office 365 Calendar API through Cronofy?

Everything is handled via your developer dashboard. Simply create a free Cronofy account and then take a look at our tutorials for further guidance.

Do I have to be a Microsoft accredited developer to use the API?

Anyone can use the Office 365 Calendar API through Cronofy – you don’t need Microsoft accreditation or certification.

Can I use Cronofy instead of the Office 365 Calendar API?

Yes, you can use Cronofy instead of any or all of the following calendar APIs: Office 365, Exchange,, Google Calendar, and Apple iCloud.

Build full calendar sync in your app

Try Cronofy for free with up to 20 users

Create your account