Exchange Calendar API

Exchange Calendar API Microsoft Exchange has been the primary on-premise calendaring solution for businesses for years. If your users are also Outlook calendar users, they're probably using an Exchange server to host the data.

Calendar integration direct with MS Exchange gets round the installation and management issues associated with Outlook plugins. However, the Exchange API can be more than a little challenging to work with due to:

Data modeling & synchronization

One of the key issues is with the data model: everything in Exchange is actually an email message.
Calendar events are modeled as emails with additional meta data. Calendars are folders that happen to contain emails with this meta data attached.

Synchronization is also tricky for Exchange calendar integration; you have two representations of an event existing in two application domains, both of which can be independently updated. To avoid conflit deadlocks and infinite update loops, you’re responsible for handling ownership and state transitions yourself.

Microsoft-specific conventions

The Exchange Calendar API itself follows a lot of Microsoft-specific conventions.

These play nicely with Microsoft development and Windows environments, but it can be nearly impossible to interact with Exchange servers from open source, Unix environments.

Adding other popular calendar services such as Google Calendar into the mix makes integration even more of a headache.

Complex privacy concerns

Calendar integration using the Exchange API also means resolving complex privacy challenges.

This is because you're required to manage personal data in a safe, secure and legal way for both yourself and users that goes far beyond what the basic Exchange API offers.

Being in a default 'all or nothing' situation where data is concerned makes it impossible to control and comply.

Ultimately, if you have enterprise users you have Exchange API calendar limitations. Unless you use Cronofy.


What is Cronofy?

Cronofy is a single API that works seamlessly across all calendar services. With Cronofy, you can integrate with Google Calendar, Exchange,, and more all from one place. Unlock all your calendar integration needs, retain all the benefits of the individual APIs, and gain a lot more advantages.

We deal with all the calendar APIs, fix privacy, and add in improved synchronization so you don’t have to. There are no limits on users or events. It’s just as easy to use five different calendar APIs as it is one, so your users can use the calendar service of their choice rather than being forced into a different workflow.

Exchange Calendar API - Cronofy

Events sourced from your app and events already in the user’s calendars are treated as separate ‘Managed’ and ‘Unmanaged’ events respectively, meaning hassle-free integrated synchronization from the word go. Furthermore, you only read the user calendar data you need for greater efficiency, better UX, and enhanced privacy.

Automatically better user experience, one API, no time wasted.

Test drive Cronofy

We provide everything you need, including a ten minute quickstart guide to get you up and running.

Cronofy includes all the features and functionality of the Microsoft Exchange Calendar API as standard, plus a host of others including:


All the calendar APIs

As well as the Exchange API, Cronofy gives you the, Office 365, iCloud, and Google Calendar APIs all in one place.


An API for all sizes and budgets

You can use Cronofy if you’re working on a personal project with one user, if you’re part of an enterprise with a billion, or anything in between.

Data Modelling

Better data modelling

Calendar events are calendar events with Cronofy, not modified email messages as they are naturally with the Exchange API.


Simple & user-friendly

Cronofy plays well with all the calendar services and programming environments, not just Windows- and Microsoft-specific ones.


Support tailored for you

Have a question? Hit a brick wall? Want to show off what you’ve made? We’re here to help, listen, and admire whenever you need us.


Flawless synchronization

Dealing with calendar syncing can be a pain for both developers and end-users. Eliminate syncing issues permanently with Cronofy.

Active Development

On-going active development

Cronofy is always under active development; new updates are rolled out regularly. If you’re the early adopter type we also have an Alpha channel where you can be the first to try new features. On top of that, we offer a 99.95% uptime SLA as standard.


Considered, complete docs

We’ve carefully developed the Cronofy API documentation to ensure it contains everything you need in an easily accessible way. Forget about trawling through tons of separate incomparable docs for different calendar services – one set of Cronofy API docs covers all the major calendar providers.


Better privacy & security

Both businesses and end-users can rest assured that their data is safe, stored and transmitted in accordance with the law, and access is given on a need-to-know basis for everyone involved. Privacy and data protection are at the heart of what we do, and go far beyond the Exchange Calendar API’s natural security and privacy handling.

Take the next step

Questions? We have answers

How do I use the Microsoft Exchange API through Cronofy?

All you need is a free Cronofy account and you’re ready to begin integrating with the Exchange Calendar API. Head on to the Getting Started section or fast track straight to the API documentation. You only need our API docs and an account with us – we handle all the Exchange bits for you.

Where do I get my Exchange Calendar API key?

Create a free Cronofy account and you’ll instantly have unified access to all the calendar services’ APIs, including Exchange Online. One key unlocks everything.

Is there a tutorial for using the Exchange Online Calendar API via Cronofy?

We’ve developed quick start guide: Getting started with the Cronofy Calendar API, along with several other tutorials to explain the details.

Do I need to be a Microsoft-registered developer to use the Exchange Calendar API with Cronofy?

No, you can use Cronofy and all its capabilities without having to be registered, accredited, or part of any program.

Do you have any sample apps or examples of Cronofy in use?

See our Sample Apps page or have a look at our Use Cases to see how the Cronofy API works in practice.

Is the Cronofy API limited to specific programming languages?

Not at all, you can use any language you like. We have users coding in all kinds of languages. However, if you’re using a common language like PHP or .NET, you may want to check out our handy code libraries for a head start.

How do I manage authentication using the Cronofy API?

We manage the authorization process automatically so you don’t need to do a thing. You simply receive one Cronofy token for the user that gives you access to all of their calendar services.

Can I use the Cronofy API to read Exchange calendar entries?

Yes, Cronofy gives you full access to Exchange calendar entries with user permission.

What are the API limits for Cronofy?

We don’t have a defined limit of requests, and we’re yet to see anyone come close to surpassing our current capabilities.

Which versions of the MS Exchange API are supported by Cronofy?

The Cronofy API supports all available versions of the Exchange API and will continue to do to give you complete peace of mind.

Can I directly replace my use of the Exchange Calendar API with Cronofy?

Yes, a single Cronofy API key will directly replace not only the Exchange Calendar API, but also the iCloud, Exchange,, and Office 365 calendar APIs. Use one of them, all of them, or a mix. It’s up to you.

I built something that uses the Cronofy API, what’s the best way to show you?

Please tweet us @cronofy or email - we love seeing projects of all types!

What are the pricing plans for Cronofy?

If you’re only creating events, Cronofy is completely free of charge. Beyond that, the API is free for the first 20 users you have. Beyond that, we offer very affordable pricing plans. We’ve made our pricing as simple and affordable as possible, meaning that are no charges for API transactions or per-event fees.

How do I find out more about Cronofy?

Arrange an informal chat with one of our team by emailing us at or filling out the form below.

My question isn’t answered here, how can I get in touch?

Drop us an email at and we’ll respond as quickly as we can.

Find out more

We'd love to learn more about your business and explore how we could help. Fill in your details and one of our team will be in touch.

Derek Edwards

“The Cronofy API allowed us to add calendar sync support to our platform in a fraction of the time it would have taken to build support for separate protocols.”

— Derek Edwards, Co-founder & CTO, CoachLogix

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