The CalDAV specification has been under development for a few years now, and at the same time we have seen increasing pressure from people and organisations in the open source world to provide a solution to their shared calendaring problems.

In evaluating the possibilities for shared calendaring, there are a number of possible approaches, but we have elected to follow the path of implementing CalDAV because we believe it is a good specification and that it will in due course gain client implementations and provide the richest user experience through those client implementations.


CalDAV is a client-server protocol specific to managing and reporting on collections of calendar resources.

As such, our intentions in developing this application are as follows:

Simplicity of Prerequisites

We have chosen to write this in PHP because we believe that PHP is a widely available web scripting language.

We have chosen to use the Apache web server because it is also widely available. This is not necessarily a requirement, but no testing has been undertaken in other PHP environments to date.

We have chosen to use the PostgreSQL database, because it is a free, open-source database, which operates on a very wide set of operating environments, and which is fully ACID compliant.

Simplicity of Setup

For the greatest ease use you should consider installing DAViCal on the Debian GNU/Linux distribution from the readily available, signed packages.

We expect to increase the level of automation and simplicity for the Debian target release in particular, although other distributions might also become easier at the same time. We do expect slightly greater installation complexity in the first few releases as we come to understand the particular problems people experience.

Simplicity of Operation

In general DAViCal should not need significant maintenance to keep it operating.

Administrative functionality will be kept as simple as possible, within the target of supporting organisations of up to several hundred staff.

The server-side smarts in DAViCal are intended to be fairly minimal in order to support CalDAV only in a manner sufficient to inter-operate with clients, and with the focus primarily on the storage of calendar resources.

Web-based Administration

General administration of the system should be through a web-based application.

Calendars will not be made available in a web-based view in initial releases. It is unlikely that calendars will ever be maintainable through a web-based client, although the server should support the use of web-based client software which works using the CalDAV protocol.