Mission

Our mission is to make web content available offline, with a primary focus on Wikipedia and other Wikimedia projects.

We focus on extracting and encoding data from Mediawiki for offline use. We would like to also add support for other wiki engines and content management systems so that this can become a ubiquitous file format for offline usages.

We even believe the file format could be flexible enough to support any kind of web data.

The general goals we want to achieve are:

• the file format is the most efficient and works on all platforms, embedded devices and desktop computers
• the file format is used by all kind of publishers and even outside the Wikimedia community
• both reader applications and content files are freely interchangeable
• everyone can implement software for this file format because it is in a open and documented standard
• there is at least one free implementation which is open source
• the free implementation can be used easily in other software to make it easy to use the file format without having to implement it

Our way to achieve these Goals

The ZIM File Format

• compresses 900.000 articles (full german Wikipedia beginning 2009) to only 1.3 GB
• features a fulltext search index
• features native category and image handling similar to MediaWiki
• is fully documented on this website - ZIM File Format
• if you need help implementing it just contact our mailinglist
• we are working on a ZIM File Archive to provide a central place to publish ZIM files including mirroring etc.

The openZIM implementation

• is all free and open source (GPL)
• is based on zimlib, a library written in C++
• provides a zimwriter to create ZIM files from a HTML dump (eg. a prepared database)
• provides a zimreader as an example how to read ZIM files; ZIMreader acts as a local webserver
• there are some more tools such as the zimdump to have a look into ZIM files or check them

What openZIM is not

• A publisher or distributor of content saved into the ZIM format. While we will make every effort to help those wanting to this we simply do not have the resources to do it ourselves. We do keep an index of known ZIM adopters at our archive page.
• This project was started by the enthusiasm of volunteers and is mainly driven by them and not business interests.
• Due to the small size of the core development team we might not be able to offer up a specific implementation of the ZIM format in your chosen programming language. We hope that by publishing the spec and working together more implementations can be written by the adopters of the format.
• In order to construct a format that aligns with our mission and spec the adoption of features will have to fit within the goals of the project.