CalDAV calendar in beta testing

We’re happy to announce that our new CalDAV service is now in open beta testing.

With CalDAV you can store your calendars on Runbox’ servers using calendar apps on your computer or smart phone. This is the first step towards a full-fledged Runbox Calendar service, as we are planning to develop an integrated web interface as well.

Please remember that this is a beta phase and that the service might be less consistent than our standard services. We therefore recommend that you back up your calendar data before and while testing it.

Setting up Runbox CalDAV

To try Runbox CalDAV in your Calendar client, just set up a new account with your Runbox username and password and as Server Address.

Note: If you are using your own domain with Runbox, the correct username format is

  • Apple Calendar users: Setup should be straight forward after selecting Add Account… > Add CalDAV Account… from the menu.
  • Outlook users: To extend Outlook with CalDAV functionality you can try the Outlook CalDav Synchronizer plugin.
  • Thunderbird users: For Thunderbird Lightning setup instructions, please see this comment.

PS: In case you are wondering what CalDAV stands for it’s Calendar Distributed Authoring and Versioning, and it’s the established standard for storing and accessing calendar information on the Internet.


20 thoughts on “CalDAV calendar in beta testing”

  1. Dear Runbox Team,

    Thank you for that nice addition to runbox ! This is definitely a must for a professional use of Runbox.

    A note to other users. If you want to use that feature with Thunderbird/Lightning:

    “In contrast to some other clients, Thunderbird/Lightning is not able to discover all the available calendar collections automatically. Instead, each calendar folder needs to be added seperately in the client. To do so, one needs to know the CalDAV URLs of the calendar folder that should be synchronized with the client.” (Source:

    So, you won’t be able to use caldav only with the URL.

    I managed to make it work by installing the pro version of Rainlendar (trial), then I went into the debug mode’s log and was able to retrieve the calendar URLS (work, home, and task). Rainleandar is able to retrived the calendar URL automatically. The URL to use with Lightning is something like this (I replaced the numbers for privacy):

    Now, it is working like a charm !

  2. Hello,

    Could you provide more details about client configuration?
    I tried with the Calendar app on my mac using my email credentials, but without success. Note that I use my own domain and thus a name%domain login.

    Thx in advance,

  3. Dave,

    Thank you for the answer. Indeed, that may be a useful information for those who use runbox with their own domain:

    DO: username = name@domain
    DONT: name%domain (as it is in the webmail)


  4. Michael: Thanks for the tip about Lightning. We are currently working on a plugin that will make it a lot easier to set up.

    Meanwhile, here’s a way to find the URL that Lightning needs to work with Runbox CalDAV:

    1. Log into with a web browser, using your Runbox usermame and password.
    2. Click Calendars.
    3. On the next screen, click the numeric link under Nodes (this is your account’s UID).
    4. On the following screen, you should see 3 links of type “Collection, Calendar”. These correspond to calendars named Home, Work, and Tasks. Click the first link.
    5. Copy the entire URL from your browser’s address bar into the Location field in Lightning.

  5. Thanks for the thunderbird hints, it worked just fine.

    The issue now is with the Android clients.

    Although they synch just fine, I haven’t found a single one that sends the invitation at all when it comes to my runbox account (I have my own domain).

    Did any of you guys come across this situation?


  6. I noticed that your SabreDAV server running on supports CardDAV for address book synchronization as well. It worked between two Android devices, after a fashion. Is this going to be supported as well (or at least kept around)?

    1. Yes, CardDAV will also be available — but how it will be integrated with Contacts in Runbox Webmail is still to be determined.

  7. I have a simple question, still related to my previous post related with the invites, and I hope some of you know the answer.

    The question is: what happens when an invitation is sent?

    Does that trigger an email in a special format, thus meaning that the email accounts in the device will be used.


    Is the DAV server responsible for sending the invite message, after a request from the client device?

    Thanks in advance.

    Carlos Dourado

  8. Hello,

    I have the same question as Carlos.
    On Apple calendar, I may add invited people but invitations are not sent.
    On the iPhone, there is no field for inviting people, when I move an event to another calendar, the field appears again and vice versa.

    As soon as all this is fixed, I’ll be happy to move everything to run box.


  9. Hi.

    Runbox is using Sabre/DAV, right?

    In that case:

    “This specification is very widely supported by clients, but even clients that do not support this specification will trigger scheduling-related behavior.

    For example, if a user creates a new event with an ORGANIZER that matches the current user, and at least one ATTENDEE, the server will automatically detect this and send invites to the relevant people.

    When a user deletes the same invite, we will automatically send CANCEL notifications to anyone affected.

    When an attendee sets their PARTSTAT to ACCEPTED or DECLINED, the server will also automatically update the organizer’s event with this information and notify him that this has happened.”

    Anyway, an explanation from runbox experts would help.

    I managed to send invitation via Thunderbird/Lightning.
    When using my mobile phone and create an event which involve invites
    1) the event is recorded on the server and correctly shown in my devices
    2) invitations are not sent

    And I second Aurelien:
    “As soon as all this is fixed, I’ll be happy to move everything to runbox”

  10. Hello,

    For those who would like to sync several calendar collections at once with Lightning, I put this as a reference, because I spent more that 2 hour trying to find the solution:
    ^. _(9>

    “This bug is present without the user enabling in options > advanced > config editor. After they do this they will need to delete the CalDav passwords in options > security > password manager. Finally, they should enable the calendars one at a time so that they know which one they are authorizing because there’s no way to tell in the authorization dialog.”

    If you enable (set to TRUE), you will be able to sync several calendar collections (e.g. yours and the one of your spouse) at once.

    …becoming addicted to caldav !!!


  11. Strange, strating from today I had to use my “” instead of just “login_name” to make caldav sync. I am using lightning.

  12. Thank you for all the tips and tricks to setup CalDAV in Lightning, but unfortunately i can successfully create the calendar but I am unable to add any event to it, or even synchronise it.
    However, in the Calendar App on my Mac, I’m able to add events and send invites, so everything seems to work correctly (also no my iPhone).

    Any insight of what I may de doing wrong in Lightning?


  13. Thank you for the comments, questions, and tips!

    Invites now work as they should, and will send an email to the invitee from your account.

    Also, you can now log in with just the localpart (the part before the @ in your email address) if you have an account.

    We have just published this Help article with details on setting up Runbox CalDAV in OS X Calendar, Thunderbird Lightning, and Outlook:

  14. Hi again.

    How about some insight as to how to configure CalDav on Android / iOS / Windows Phone?

    Noawadays, it’s as important as desktop/laptop clients!

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