MWI Device Description Working Group (CLOSED)

The objective of the Mobile Web Initiative is to enable access to the Web from mobile devices. It is envisaged that this will typically require adaptation of Web content, which relies on device knowledge. The Device Descriptions Working Group (DDWG) had been given the task of defining the means by which such knowledge would be made available to adaptation technology.

The Working Group operated from May 2005 to December 2008, and has now been closed.

Latest News

DDR Simple API is a W3C Recommendation

[December '08] The Mobile Web Initiative Device Description Working Group has published the W3C Recommendation of Device Description Repository Simple API. Web content delivered to mobile devices usually benefits from being tailored to take into account a range of factors such as screen size, markup language support and image format support. Such information is stored in "Device Description Repositories" (DDRs). This document describes a simple API for access to DDRs, in order to ease and promote the development of Web content that adapts to its Delivery Context. See the original press release.

Draft of Structures Note published

[December '08] The Working Group also published a Group Note of Device Description Structures, an expression language for the structured categorization of devices in content adaptation.

DDWG enters 'maintenance mode'

[December '08] The DDWG enters 'maintenance mode', where volunteers will be keeping the public pages, wiki, mailing list and blog up to date with information relating to the technologies defined by the group. Any related new work will be considered elsewhere within W3C. The group's formal status is 'closed'.

DDWG work comes to an end

[June '08] After dealing with the public comments on the API, and the recent demonstration of implementations, the group has agreed that no further work is to be done. Some current drafts of related work will be published, and there may be some activity on the wiki. There will be a request to transition the specification further along the W3C Recommendation track.

Implementations of the DDR Simple API

[June '08] Several implementations of the DDR Simple API were demonstrated at the group Face-to-Face. A report is now available.

Group Face-to-Face - the DDR Simple API in action

[June '08] The group meets in France, where demonstrations of implementations of the new API are expected to take place.
Chart of the API classes and methods
(Chart available in JPG 100k, PNG 138k, SVG 684k)

Final editors' draft of DDR Simple API

[June '08] The editors of the DDR Simple API have, in consultation with commenters following the Last Call publication, made available to the public the most recent and final draft of the API specification. It is expected that this specification will be put forward as a Candidate Recommendation. The group has resolved that the specification will move from a Candidate to a Proposed Recommendation upon the presentation of three independent implementations that claim conformance with the specification. A review of known implementations is on the agenda for the Face-to-Face meeting scheduled for 19-20 June.

Core Vocabulary Note published

The DDR Core Vocabulary was published as a W3C Working Group Note on 14 April 2008. This provides a vocabulary of 13 essential properties (Vendor, Model, Version, Display Width, Display Height, Display Color Depth, Input Devices, Markup Support, Stylesheet Support, Image Format Support, Input Mode Support, Cookie Support and Script Support) within two aspects ("device" and "webBrowser").

Draft of DDR Simple API published

The DDR Simple API was published as a draft of an intended W3C Recommendation on 4 April 2008. This document describes an API (comprising 6 interfaces and 6 classes) that is capable of being implemented in many programming languages and that provides a simple means of accessing device descriptions held in a repository. Such information is expected to be used to adapt responses to HTTP requests from (predominantly mobile) Web-enabled devices.

Editors' Draft of Simple API (Java binding)

[Feb.'08] In advance of the Seoul Face-to-Face, the editors of the DDR API Specification document (internally known as the Simple API) have completed the latest draft of a Java binding, available for public inspection. The Simple API is an easily implemented and easily adopted interface to a Device Description Repository. The DDWG is ensuring that the Simple API has both simple default-based convenience methods and robust type-safe methods, employs the factory pattern and is extensible (to an Advanced API that may later be devised by another W3C group). Final decisions on the Simple API will be taken in Seoul in advance of a publication as a FPWD.

Updated Core Vocabulary

[Feb.08'] The core vocabulary has been updated, and now contains Aspect information for the Property Terms. It is expected that the DDR API will support Aspects, and that these may be defined in the vocabulary of properties used by the API. This core vocabulary, including the Aspects, will be supported by the proposed Simple API for DDRs.

New publications

[Dec.'07] The first draft of a core vocabulary for use with a Device Description Repository has been published. While additional vocabularies can be accommodated by a DDR, the proposed core vocabulary is intended to be used as part of any solution that uses static device information to facilitate content adaptation (particularly as necessitated by mobile Web-enabled devices).

[Dec.'07] The final version of the Requirements document is published. This outlines the motives for key DDR characteristics through illustrative use cases.

[Oct.'07] Two of the group's documents (Landscape and Ecosystem) have been updated and re-published. An announcement was made on the public list and blog. This are the final updates to the documents.

Vocabulary contribution process is live

[June'07] As announced last month, the DDR Core Vocabulary contribution process is now active. See the details on the DDWG wiki.

Vocabulary contribution process to go public

[May.'07] In order to create a Core Vocabulary for the proposed Device Description Repository technology being defined by DDWG, a public process will be put into action. This will enable registered W3C account holders and existing W3C members to propose entries in the vocabulary. This work will also be submitted to the W3C UWA ontology so that the wider community will benefit. The launch will be announced on the public mailing list.

DDWG holds Face-to-Face meeting

[Apr.'07] The DDWG held a face-to-face meeting in Darmstadt, Germany at the offices of T-Online attended by active participants of the DDWG, some invited members of the BPWG and other observers and was co-located with meetings of the BPWG and POWDER group over a five day period. A summary has been posted via the public mailing list.

OMA DCAP updates DDWG on work status

[Mar.'07] In a public liason statement [Zip], the OMA Device Capability (DCAP) group has informed DDWG of their progress with respect to Device Profile Requirements and the updated charter of the OMA DCAP group. The updated charter now explicitly includes liaison with DDWG as part of the scope of its work.

DDWG goes public

[Feb.'07] In keeping with the new group charter, the DDWG has launched a wiki and a blog in which the public will be encouraged to observe the evolution of the Device Description Repository and associated technologies. The primary channel of public contribution remains the public mailing list, and the group plans to reflect public contributions in the wiki. Summaries of weekly meetings, major DD-related events and significant updates to the evolving documents will be announced on the mailing list and the blog. RSS feeds will keep everyone informed of changes in wiki content and new blog postings.

DDWG Charter 2

[Dec.'06] The W3C is pleased to announce that the DDWG is rechartered to enable the development of globally accessible data and service repositories for use in content adaptation. The group is part of the Mobile Web Initiative (MWI), which was launched in 2005 with the help of sponsors to make Web access from a mobile device as simple, easy, and convenient as Web access from a desktop device.

For more news, visit the DDWG blog

Published Documents

The Group published one W3C Recommendation:

The Group completed several W3C Working Group Notes.

Note that these new documents were developed in the wiki where contributions are welcome.


The following workshops have been held in which the subject of device descriptions has been raised:

Joining the group

The group has now been closed; should you be interested in restarting work in this area, please contact Matt Womer at <>.

The working group chair was Rotan Hanrahan. The W3C Team contact was Matt Womer.

Contributing to the group

Contributions to the group from non-members may be submitted through the public mailing list by sending email to

The group may use contributions in whole or in part in other parts of the publications on this site, including the wiki and blog and any formal publications. The group may, at its discretion, make special arrangements to facilitate contributions (e.g. in the case of regular contributors).

Patent Policy

This Working Group operated under the W3C Patent Policy (5 February 2004 version). To promote the widest adoption of Web standards, W3C seeks to issue Recommendations that can be implemented, according to this policy, on a Royalty-Free basis. Deliverables announced in the charter of the group are covered by the W3C Patent Policy and its disclosure requirements. Information about patent disclosures by group participants is available.

The group has no control over material presented to the group by persons outside of the group (specifically the public) via public access mechanisms such as the public mailing list. Incorporation of any material donated in this manner shall be subject to agreement from the donor to accept responsibility for such contributions in a manner consistent with the W3C policy on contributions.

This is a device-friendly page, intended for use on large and small browsers that can display XHTML 1.1 (Transitional).

Matt Womer, W3C Team Contact for the Device Description Working Group
Rotan Hanrahan, Chair of the Device Description Working Group

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