Better Calendar API Integration

“The API was brilliant to work with.”

— Greg Dickson, Developer, Appointedd

Connect to your customers' calendars

Microsoft’s personal email hosting has had several names over the years: Hotmail, Live, and of course, its most recent name, is used by millions of people across the globe, meaning that if you want to reach your customers you have to integrate with it.

However, not every customer uses There will inevitably be customers who favour Apple Calendar or Google Calendar instead. Building integrations with each API individually costs time and money. Maintaining them costs even more.

A better way to build

Cronofy allows you to create features for multiple calendar services while only needing to work with one API.

Whatever you build with the Cronofy Calendar API will work with, Office 365, Microsoft Exchange, iCloud, and Google Calendar.

That means that you can create a more user-friendly experience with advanced functionality and a workload that’s five times less than if you'd worked with each API individually.

Cross-calendar synchronization

When you create an event in and invite someone who uses Apple Calendar or Google Calendar, two versions of the event are created. Should any changes be made, there's no guarantee these will sync across. This could cause all sorts of confusion for your customers.

When events are made using Cronofy, it doesn't matter what calendar service customers use. Everything updates in real-time, preventing any double-bookings or potential confusion.

Greater user privacy integration is limited because it offers an all-or-nothing approach to accessing customers’ calendar information. That means that you can either access all of their personal details, or offer them a lesser user experience but greater privacy.

With Cronofy, you can create a connection that can see when a user is free or busy without accessing this personal information. Users’ private data stays private but they also don’t risk double-booking themselves.

Try Our API

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

Cronofy also offers...


Personal support

We’re here to answer your questions and help with any problems whenever you need assistance.


Global environment

Cronofy has been built for easy integrations across all languages and services, not just Microsoft and Windows.

High Uptime

99.95% uptime SLA

Cronofy is highly reliable, with a minimum average uptime of at least 99.95% guaranteed.

Active Development

Always in active development

The Cronofy API has been under active development since its creation, and we frequently release new features and list upcoming alpha features.

Calendar Compatibility

All-in-one API access

Get the full, Exchange, Office 365, iCloud and Google Calendar APIs all through Cronofy. Best of all, you only need one set of docs to make it happen.


Documentation for developers

Written by our own in-house development team, our API docs are logical, consistent, and concise. One set of Cronofy docs is all you need.

Data Modelling

Optimized data handling

Security and privacy are top priorities, so businesses and end-users can rest assured that data is handled legally and safely for all parties above and beyond the API’s standard.


Synchronization and scalability

One user or one billion, Cronofy scales to your requirements. Advanced synchronization means calendars that are always accurate.


Finely-tuned privacy

The standard API requires a lot of work to meet minimum privacy and security standards. Cronofy’s better data modelling means peace of mind for developers, businesses, and end users.

Erin Chmelik

“Cronofy is an excellent value add to our clients, who constantly move between using JobAdder and their external calendar during their day, improving their overall workflow.”

— Erin Chmelik, Product Manager, JobAdder

Cronofy/ Calendar API FAQs

How do I get Calendar API access?
Sign up for a free Cronofy account and then follow our quick Getting Started tutorial that covers everything you need to know.

Where do I get my Calendar API key?
The Cronofy API key includes calendar API access as well as all the other major calendar APIs – sign in to your Cronofy account for instant access.

How much does Cronofy cost?
We’ve developed a scalable pricing system so that Cronofy is affordable whether you’re experimenting with a hobby project or designing a system for millions of users. If you’re just creating events, our API is free. It’s also free for the first twenty users you have. Beyond that, it’s one flat free without any charges for API transactions or events. See our pricing page for details.

Where can I see Cronofy being used?
As the Cronofy API plays a backend role in companies’ systems, we’ve created Sample Apps and Use Cases so you can get a better idea of what you can do with our API and how it works.

What programming languages are compatible with the Cronofy API?
You can code in whatever language you like; we have developers using C#, Java, .NET, PHP, JSON, and pretty much any language you can think of. If you’re using a common language like PHP or .NET, check out our code libraries.

How does the Cronofy API handle authentication?
It’s automatically managed on our side so there’s one less thing for you to do. A single Cronofy token for a user gives you the required access to all their calendar services.

What are Cronofy’s API limits?
We don’t put a fixed number of the amount of requests you can have, and we’re yet to see anyone come close to surpassing our current capabilities.

Can I replace the Outlook Calendar API with Cronofy?
Yes, your Cronofy API key replaces the Exchange, iCloud, Exchange,, Google Calendar, and Office 365 calendar APIs. Use any or all of them via Cronofy – the choice is yours.

I worked on a project that uses Cronofy’s API, what’s the best way to tell you?
Please tweet us or email - we love seeing your creations!

I’m not a Microsoft-registered developer. Can I still use the Calendar API with Cronofy?
Absolutely, you don’t need to be Microsoft registered, accredited, or certified in any way to use our API or the API.

I have another question, how can I contact you?
Feel free to email us any time and we’ll try to help! If you have a support query, please get in touch at

To find out more about Cronofy, book a demo or email

Try our API

Get started for free with up to 20 users. Don't pay until you go live