Connect any CalDAV calendar to OneCal
OneCal supports CalDAV, the open standard behind most calendar servers, allowing you to connect Fastmail, Nextcloud, Zoho, a self-hosted server, or any other CalDAV calendar the same way you connect Google Calendar, Outlook, or iCloud, and use it with every OneCal feature.
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What is CalDAV?
CalDAV is an open internet standard for reading and writing calendar data, used by email providers like Fastmail and Zoho and self-hosted tools like Nextcloud, Radicale and Baïkal.
- Connect any calendar server that supports CalDAV, not just the big three providers
- Works exactly like a Google Calendar, Outlook or iCloud Calendar once it is connected
- Use it in all OneCal features like calendar sync, scheduling links, the unified calendar view and more
- Ask the AI Assistant about your CalDAV events, or reach them from Claude and ChatGPT through the MCP server
Works with all major CalDAV providers
If your provider offers a CalDAV address, OneCal can connect to it. Here are some of the most common ones.
Fastmail
Email provider
Connect your Fastmail calendars with the CalDAV address from your Fastmail settings and an app-specific password.
Nextcloud
Self-hosted
Bring calendars from your own Nextcloud instance into OneCal, whether it runs at home or on your company server.
Zoho Calendar
Business suite
Connect Zoho Calendar over CalDAV and use it like any other calendar in OneCal.
Radicale
Self-hosted
A lightweight, open source CalDAV server. Connect it with its server address and your account details.
Baïkal
Self-hosted
Connect calendars from a Baïkal server, a popular lightweight CalDAV and CardDAV server.
Synology Calendar
NAS
Connect the calendar app on your Synology NAS through its CalDAV address.
mailbox.org and Posteo
Email provider
Privacy-focused email providers that make their calendars available over CalDAV.
Any other CalDAV server
Open standard
Kerio, Zimbra, SOGo, Open-Xchange and many more. If it supports CalDAV over HTTPS, OneCal can connect to it.
Connect a CalDAV calendar to OneCal in three steps
Connecting a CalDAV Server is as easy as it gets, we just need a server address, your username, and an app-specific password.
- 1
Enter your server address
Each provider's CalDAV server address is different, read our docs or ask the AI Assistant for each provider's server address.
- 2
Enter your username and app-specific password
Use your email or username and an app-specific password. Most providers let you create an app-specific password in their security settings.
- 3
Choose the calendars to import
An account can have multiple calendars, choose the ones you want to use in OneCal.
Everything OneCal does, now with CalDAV
A CalDAV calendar works with the OneCal features you already use.
Calendar Synchronization
Sync
Use CalDAV calendars as the source or destination of any calendar synchronization, one-way or multi-way, and decide which details are copied.
Unified Calendar View
Calendar view
See and manage CalDAV events next to all your other calendars. Create, edit and delete events, RSVP and join meetings from one place.
Scheduling Links
Scheduling
Scheduling links check your CalDAV calendars for conflicts, so you are never double-booked.
Mobile Apps
iOS and Android
Your CalDAV calendars show up in the OneCal mobile app, so you can manage them on the go.
AI Assistant
AI
Ask the OneCal AI Assistant what is on your CalDAV calendar, create events or check your availability by chat.
Calendar MCP Server
AI
Give Claude, ChatGPT and other MCP clients access to your CalDAV events through the OneCal Calendar MCP Server.
Secure by design
Your credentials stay protected
OneCal connects to your CalDAV server over HTTPS only and stores your app-specific password encrypted. You can remove the connection at any time from your OneCal account.
CalDAV integration FAQ
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