3e Calendar

3e is full scale client-server calendaring system which allows users to manage their calendars, manipulate events and coordinate meetings with other users. It provides complete set of robust enterprise calendaring features such as calendar sharing, subscriptions, on behalf scheduling, attachments and much more.

Save time and effort

Finding out availability options for people attending the events has never been so simple. Create an event in your calendar, add attendees from the address book, click to display free/busy information. Free/busy will be shown for everybody who has one of the supported online calendars and shares the availability information. Then adjust date and time to a slot when everybody is free and save the event to send the invitations.

Save time and effort
3e Calendar can access and retrieve availability information for users of following online calendar systems.
3e Calendar Google Calendar Zimbra IceWarp Kerio Connect Bedework DAViCal
3e Calendar Google Calendar VMWare Zimbra IceWarp Kerio Connect Bedework DAViCal
Just turn on

Just turn on

3e Calendar is a standalone calendar system. It just adds calendar functionality to whatever you currently use – there is no need to change email system or database server or any other piece of your infrastructure. Setup calendar server, create accounts for your users (or synchronize the accounts with your corporate LDAP directory), install plugins to their favorite calendar applications and you are ready to schedule effectively.

More time to work

Remember answering a phone call by looking into the calendar to tell when you are available? With 3e Calendar will be your availability information (of course free/busy only not event details) automatically accessible by others – no special calendar links exchange in advance is necessary. Everyone knowing your email will be able to get the very same information you would provide over a phone or an email completely without your involvement.

More time to work
Know more know better

Know more, know better

Past events in the calendar are valueable as well as those in the future. Get last month time sheet, analyse how the employees travel to the meetings, build calendar reports to gather usefull information. 3e Calendar provides an interface to integrate the calendar with other corporate systems or query and get desired calendar data to use them in any other way.

See in action

Check out the screenshots of 3e Calendar inside calendar applications or the screenshots of available administrative tools you can use to manage your 3e calendars. Click to enlarge and open the gallery.

Using in calendar apps


External free/busy

IconAvailability information is provided not just for the persons from your organization, but for people from the other companies or users of other services too.

Calendar sharing

IconCalendars can be shared to read or write based on user or group permissions. Everybody can find calendars eligible to subscribe by just a few clicks.


IconOne calendar account can be used with more digital identities. Whatever user name and domain name combination is possible.


IconFiles can be attached directly to the events in similar manner as to the emails. They are distributed to all attendees of the event automatically.

Zero configuration

IconThe only required information to setup the account as a user is the email address. The rest is discovered from the network automatically.

Easy administration

IconIntuitive and user friendly web administration tool is provided to make the management and administration as painless as possible.

On behalf scheduling

IconThe meetings can be scheduled on behalf of someone else if the original meeting organizer can not or does not want to do it.

Automated processing

IconInvitation responses or event updates are handled automatically even between different servers. There is no need to open email attachments to save data into the calendar.

Recurrency done right

IconRecurrent events are handled properly and you can do exceptions and updates without messing up your calendar.

Web export

IconCalendars can be exported as web calendars. You can connect them or subscribe to any legacy calendar application you want if they support web calendars.

Notifications branding

IconEmail notifications from the calendar such as meeting invitations or updates can be customized to match your corporate ID.

3e Calendar specification

  • Easy Event Exchange communication protocol
  • Standards based event storage (iCalendar) and scheduling communication (iTip, iMip)
  • User or group based calendar ACL and subscriptions
  • On behalf scheduling
  • Free/busy from external systems (Google, Zimbra, IceWarp, DavIcal, Bedework supported)
  • User and domain aliasing
  • Account auto-configuration
  • Managed attachments support
  • Multiple database backends (PostgreSQL, MySQL or SQLite supported)
  • LDAP directories support with custom queries
  • IPv4 and IPv6 supported
  • Email notifications branding

System recommendations

500Mhz CPU, 512MB RAM, 5GB disk space (<50 users)
1Ghz CPU, 1024MB RAM, 20GB disk space (>50 users)

Fedora and Ubuntu Linux (other Linux distributions may work, but are not tested)

PostgreSQL or MySQL database, SQLite is supported, but not recommended for production systems

DNS server, SMTP server

LDAP server (optional)

Frequently Asked Questions

Can I use 3e Calendar with my current Google (or other) calendar?

Do I automatically disclose my calendar data with others?

Why is free/busy from CalDAV servers not supported?

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Technical support
+420 776 172 646

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