Integrate your app with the Apple iCloud Calendar API

Integrate with Apple Calendar without using CalDAV with the Cronofy Unified Calendar API

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Cronofy Calendar API

Connecting schedules

There are millions of iPhone users out there.

Allowing them to connect their Apple Calendar to your application creates a better user experience and puts you one step ahead of your competition.

However, it’s not easy.

The only way to connect to iCloud is using CalDAV. This client/server document protocol is used to submit and retrieve Apple Calendar documents.

Unfortunately, CalDAV can be a challenge for developers used to more commonly styled HTTP APIs.

This mean that many applications that could benefit from calendar sync don’t take advantage of it and their users miss out.

Using Cronofy’s unified calendar API, you can solve these problems and more.

Calendar sync for iPhone, iPad, and Mac.

Real-time Calendar Sync

Full calendar sync made easy

With traditional calendar integration, two versions of an event exist in two different calendar services.

Both can be updated independently, meaning that if an event is cancelled or rescheduled, one party may miss out on important details.

To avoid conflict deadlocks and infinite update loops, you’re responsible for handling ownership and state transitions.

The Cronofy API resolves these synchronization challenges.

Changes to calendar events are idempotent. You don’t have to worry about if an event already exists or not, you just tell us what state you want to it be in and we’ll make the necessary changes.

Cronofy also differentiates between events sourced from your application (‘Managed’) and events already in the user’s calendars (‘Unmanaged’) to ensure that you have reliable integration from the start.

Bring calendar sync to your customers

Calendar integration

Deliver great scheduling features to your users

Only allowing users to connect to one calendar service can result in a poor user experience.

It could even mean that they don’t use your product and go to a competitor instead.

Connecting software to multiple calendar services, however, is a costly investment.

You have to spend time not only creating individual connections to each calendar API, but also maintaining those connections and ensuring it works with previous versions of each calendar service.

When you use Cronofy, you can code for just one API and connect your software to iCloud, Google Calendar, Office 365,, and Exchange.

All the maintenance is handled by us, meaning that you have more time to spend on creating a great product for your customers.

Calendar sync for Apple Calendar.

Free/busy data


The iCloud Calendar API offers limited connectivity options.

Either your application can access everything in a user’s calendar, or nothing. There is no other option.

Unless you use Cronofy.

With Cronofy, you can customize how much of a user’s calendar your software has access to.

If it only needs their free/busy data, you can set it up so that that’s all it will see.

This free/busy data can be hosted on our EU or US servers.

Cronofy also offers...


All calendar APIs

Integrate with the iCloud,, Office 365, Exchange, and Google Calendar APIs via Cronofy for universal calendar functionality minus the hassle.



Avoid dealing with frustrating CalDAV/Apple Calendar API integration and spend your time on interesting parts of web development - Cronofy does the boring stuff for you.


Full documentation

A single concise set of Cronofy documentation is all you need for all the calendar APIs. We’ve carefully developed our API documentation for clarity and ease of use.



Enjoy peace of mind with our standard 99.95% uptime SLA.



One user or one billion, Cronofy scales for your needs.


Active development

We release new features and updates regularly.


Fast syncing

Cronofy's advanced approach to synchronization means your users always have calendars they can rely on.


Better privacy

We handle privacy more effectively for both businesses and end-users, and we’re always on hand to help.


A voice

We have a public platform for ideas and feedback, and actively implement user suggestions.

The API was brilliant to work with.

Greg Dickson
Developer - Appointedd

Explore our customer stories

Cronofy/iCloud Calendar API FAQs

How do I use the Apple iCloud Calendar API via Cronofy?

Sign up and take a look at our API documentation. Use our docs instead of the iCloud API docs and connect your calendar in a click from your Cronofy account dashboard.

Where do I get my Cronofy iCloud Calendar API key?

To get your universal key, create your free Cronofy account.

What pricing options are available for Cronofy?

Cronofy is free to test with up to twenty users. For more details, visit our pricing page.

Global brands deliver better scheduling with Cronofy


Build full calendar sync in your app

Set up your demo account and try our API for free with up to 20 users

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