One API for all calendars
Unified Calendar API
For over three years, we've synchronized hundreds of millions of events across iCloud, Outlook, and Google Calendars, and we know the pain of dealing with multiple calendar APIs. Our Unified Calendar API combines years of trial and error to make it possible to communicate with iCloud, Outlook, and Google Calendar using a single API.
Syncs Executed
30+Million
Events Synced
500+Million
API Success Rate
99.9%
Why use the OneCal Unified Calendar API?
We've been ironing out our calendar synchronization algorithms for years, ensuring events can be synced across all major calendar providers. As a result, we've built a Unified Calendar API that's very reliable and proven to work across thousands of calendars and millions of events.
Support for iCloud, Outlook and Google Calendar
Our Unified Calendar API works with iCloud, Outlook, and Google Calendar, ensuring you focus on shipping fast and growing your company instead of figuring out the gotchas of each calendar provider.
Proven to be reliable
OneCal is at the forefront of the calendar synchronization space, helping thousands of professionals and companies automatically sync their calendars in real-time. Our Unified Calendar API is tested daily by syncing hundreds of thousands of events across all major providers, and our customers are always happy with the service.
Easy to Use & Build on Top
Aside from using our Unified Calendar API to sync events across different calendar providers, we also use it for our Scheduling Links and Calendar View feature, enabling users to share their schedule via a link, as well as view all their events across multiple calendars in one place. Our Unified Calendar API makes it a breeze to build everything on top of third-party calendar API.
Unified Calendar API FAQ
- What is the Unified Calendar API?
- A Unified Calendar API allows developers to integrate multiple calendar providers (Google Calendar, Outlook, iCloud, etc.) into their applications with a single, consistent interface.
- Which calendar providers are supported?
- We support Google Calendar, Microsoft Outlook (Office 365, Exchange, Outlook.com), and iCloud.
- Who is this API for?
- It's designed for SaaS applications, productivity tools, CRMs, booking platforms, HR systems, and any app needing seamless multi-calendar integration.
- Do you provide SDKs or client libraries?
- Yes, we offer an SDK for Node.js. SDKs for Python, PHP, and Java are coming soon.
- How do I authenticate calendar users?
- We use OAuth 2.0 for Google and Microsoft and App-Specific Passwords for iCloud.
- Can I create, update, and delete calendar events?
- Yes, you can CRUD (Create, Read, Update, Delete) events across all supported calendars.
- Do you support recurring events?
- Yes, we fully support recurring events, including modifications to individual occurrences.
- Is there a free plan?
- Yes, we offer a free tier with limited API calls. Paid plans provide higher limits and premium support.
Build Your Next App with Our Unified Calendar API
With the OneCal Unified API, you'll enjoy building features that really matter and leave the tedious calendar APIs across all your calendar providers to us.