Web of Things Working Group Charter

The mission of the Web of Things Working Group is to counter the fragmentation of the Internet of Things (IoT) through the specification of building blocks that enable easy integration of IoT devices and services across IoT platforms and application domains. These building blocks complement and enhance the use of existing standards; provide a common description across different ecosystems, standards, and communities; and provide prescriptive definitions where appropriate.

Join the Web of Things Working Group.

Charter Status See the group status page and detailed change history.
Start date 3 October 2023
End date 2 October 2025
Chairs Sebastian Kaebisch (Siemens), Michael McCool (Intel), and Michael Koster (Invited Expert)
Team Contacts Kazuyuki Ashimura (0.2 FTE)
Meeting Schedule Teleconferences: Weekly with additional topic specific calls as appropriate.

Face-to-face: We will meet during the W3C's annual Technical Plenary week; additional face-to-face meetings may be scheduled by consent of the participants, with no more than four (4) face-to-face meetings in total per year.

Motivation and Background

Currently the IoT is highly fragmented with a multitude of different standards and ecosystems which often do not easily interoperate. This is a concern as much of the value of the IoT can only be obtained when devices and services from different vendors can be used together. The standards developed by Web of Things (WoT) are intended to address this issue by defining additional building blocks to allow systems from different "ecosystems" to interoperate. The WoT WG will focus on IoT standards for commercial and industrial deployments and ecosystems. As part of its work the WoT WG will aim to build strong liaisons with related organizations.

As a continuation of the work in the previous charter, this working group is tasked with the standardization or extension of the building blocks to address the use cases and requirements identified by the Web of Things Interest Group (IG) to advance the Web of Things. The WoT building blocks complement and integrate existing and emerging IoT standards using Web technologies. As a result, the building blocks enable cross-platform and cross-domain interoperability in the IoT.


During this charter, the Working Group would work on the following:

Support New Use Cases:
Address the requirements of new use cases, such as Digital Twins and integration with edge and cloud systems.
Update and Refactor Existing Specifications:
The WG will add new features, address issues discovered during implementation of the current set of specifications, and reorganize material between documents as appropriate. These are not be limited to backward-compatible updates, however great care will be taken to minimize the impact on existing implementations.
Support WoT Interoperability:
The WG will improve out-of-the-box interoperability and enable the integration of WoT into other ecosystems and communities. Thus, the WG will define core binding and profiling mechanisms, and define additional profiles and bindings, as appropriate.
Improve Management of TDs:
Additional mechanisms around for the management of TDs are needed to improve workflows that use them. Thus, the WG will update the Discovery specification with additional features, including geolocation.
Increase Descriptiveness of TDs:
The WG will work on increasing the descriptive power of TDs to allow using them in additional use cases. This includes describing dynamic resources, historical values (timeseries), better describing payloads, both static and dynamic geolocation information, manageable actions and more precise definitions of data schemas for each type of operation.
Improve Security and Privacy:
Define modular security vocabularies, simplify the use of security schemes, and other work as appropriate.

Out of Scope

The following features are out of scope, and will not be addressed by this Working group.

Application- and domain-specific metadata vocabularies:
The Working Group is restricted to work on cross-domain vocabularies.
APIs and security frameworks specific to particular platforms external to the W3C:
The scope of the Working Group is restricted to APIs and security frameworks that are applicable across platforms. We will not define new security mechanisms but will use existing mechanisms and best practices.
Modification of protocols:
If during work on bindings, it becomes apparent that changes are needed to protocols, the Web of Things Working Group will rely on the organization responsible for the protocol to make the changes. It is out of scope for the Working Group to standardize such changes itself.


Updated document status is available on the group publication status page. The specification names given below are not exact titles as we are currently discussing how to best manage versioning and how to reflect this in the title of documents. Final titles will include "Web of Things".

Normative Specifications

The Working Group will deliver the following W3C normative specifications:

Architecture (Update)

This specification defines the Web of Things architecture, terminology, fundamental concepts, architecture and deployment patterns, and horizontal security and privacy requirements. It introduces and gives an overview of the family of WoT building block specifications described below.

Draft state:No draft

Expected FPWD:Q1 2024

Expected CR Transition:Q4 2024

Expected PR Transition:Q2 2025

Expected REC Transition:June 2025

Adopted Draft: This will be an update of the current Web of Things (WoT) Architecture specification published at https://www.w3.org/TR/wot-architecture11/, as a Proposed Recommendation on 11 July 2023.

Discovery (Update)

This specification defines a Discovery process for WoT, and would be a backward-compatible update to the existing WoT Discovery Specification.

Draft state:No draft

Expected FPWD:Q1 2024

Expected CR Transition:Q4 2024

Expected PR Transition:Q2 2025

Expected REC Transition:June 2025

Adopted Draft: This will be a revision of the current Web of Things (WoT) Discovery specification published at https://www.w3.org/TR/wot-discovery/, as a Proposed Recommendation on 11 July 2023.

Thing Description (Update)

This specification defines the Web of Things Thing Description information model and its JSON-LD serialization. This deliverable will add new features and address issues discovered during implementation.

Draft state:No draft

Expected FPWD:Q1 2024

Expected CR Transition:Q4 2024

Expected PR Transition:Q2 2025

Expected REC Transition:June 2025

Adopted Draft: This will be a further iteration of the current Web of Things (WoT) Thing Description specification published at https://www.w3.org/TR/wot-thing-description11/, as a Proposed Recommendation on 11 July 2023.


This specification defines a profiling mechanism to enable out-of-the-box interoperability between Things and Consumers which conform to a prescriptive set of constraints, and defines at least a first basic HTTP-based profile.

Draft state: Working Draft

Expected CR Transition:Q4 2023

Expected PR Transition:Q1 2024

Expected REC Transition:Q3 2024

Exclusion Draft: https://www.w3.org/TR/2020/WD-wot-profile-20201124/
associated Call for Exclusion on 2020-11-24 ended on 2021-04-23
Produced under Working Group Charter: https://www.w3.org/2020/01/wot-wg-charter.html

Profile (Update)

This specification is an update to the WoT Profile specification, with additional normative profiles as appropriate.

Draft state: No draft

Expected FPWD:Q2 2024

Expected CR Transition:Q4 2024

Expected PR Transition:Q2 2025

Expected REC Transition:June 2025

Other Deliverables

Other non-normative documents may be created including:

  • Use Cases and Requirements;
  • Security and Privacy Guidelines (to be published as a W3C Note);
  • Test suite and implementation reports for each specification;
  • Primer or Best Practice documents to support web developers when designing applications.
  • WoT Scripting API (W3C Note): This document will present a design for a Scripting API that will support exposing and consuming Thing Descriptions while providing a high-level interface to interactions that is independent of protocol. The work will continuously align with the WoT TD specification. Besides these efforts, alignment with the WoT Discovery specification will be the main topic.
    Draft state: Group Note
  • Binding Documents for Specific Protocol, Payload and Ecosystems (W3C Notes): These documents specify how protocols and payload formats should be used to allow integration of specific classes of IoT systems and ecosystems.


  • September 2023: First teleconference
  • September 2023: First face-to-face meeting (TPAC 2023, Sevilla, Spain)
  • Q4 2023: Requirements and Use Cases updated
  • Q4 2023: CR Transition for Profile deliverable
  • Q1 2024: FPWD for updated Discovery, Thing Description, and Architecture deliverables
  • Q1 2024: PR Transition for Profile deliverable
  • Q2 2024: FPWD for updated Profile deliverable
  • Q3 2024: REC Transition for Profile deliverable
  • Q3 2024: Updated publication of WoT Security and Privacy Guidelines as a Note
  • Q4 2024: CR Transition for updated Discovery, Thing Description, Architecture, and Profile deliverables
  • Q4 2024: Updated publication of Bindings as Notes
  • Q1 2025: Updated publication of Scripting API as a Note
  • Q2 2025: PR Transition for updated Discovery, Thing Description, Architecture, and Profile deliverables
  • June 2025: REC Transition for updated Discovery, Thing Description, Architecture, and Profile deliverables

Success Criteria

In order to advance to Proposed Recommendation, each normative specification is expected to have at least two independent interoperable implementations of every feature defined in the specification, where interoperability can be verified by passing open test suites, and two or more implementations interoperating with each other. In order to advance to Proposed Recommendation, each normative specification must have an open test suite of every feature defined in the specification.

A testing plan will be developed for each specification, starting from the earliest drafts.

To promote interoperability, all changes made to specifications in Candidate Recommendation or to features that have deployed implementations should have tests.

Each specification should contain sections detailing all known security and privacy implications for implementers, Web authors, and end users, as well as recommendations for mitigations. There should be a clear description of the residual risk to the user or operator of that protocol after threat mitigation has been deployed.

Each specification should contain a section on accessibility that describes the benefits and impacts, including ways specification features can be used to address them, and recommendations for maximising accessibility in implementations.


For all specifications, this Working Group will seek horizontal review for accessibility, internationalization, privacy, and security with the relevant Working and Interest Groups, and with the TAG. Invitation for review must be issued during each major standards-track document transition, including FPWD. The Working Group is encouraged to engage collaboratively with the horizontal review groups throughout development of each specification. The Working Group is advised to seek a review at least 3 months before first entering CR and is encouraged to proactively notify the horizontal review groups when major changes occur in a specification following a review.

Additional technical coordination with the following Groups will be made, per the W3C Process Document:

WoT-related W3C Groups

Web of Things Interest Group
This Working Group Charter covers those aspects that the Web of Things Interest Group (charter here) believes are mature enough to progress to W3C Recommendations. As a continuation of the work in the previous charter, this working group is tasked with the standardization or extension of the building blocks identified by the use cases resulting from the work of the Web of Things Interest Group (IG) as being important to advance the Web of Things.
Web of Things Community Group
For collaboration on community outreach of the WG reports to increase adoption and implementation, as well as collecting feedback from the global community. Meetings held in English.
Web of Things Japanese Community Group
For collaboration on community outreach of the WG reports to increase adoption and implementation, as well as collecting feedback from the Japanese community. Meetings held in Japanese.

Other W3C Groups

JSON-LD Working Group
For collaboration on JSON-LD features and WoT use cases.
Efficient Extensible Interchange Community Group
In relation to efficient interchange for Thing Descriptions.
Web and Automotive Business & Working Groups
For collaboration on technologies and requirements relating to connected cars and the Web of Things.
Device and Sensors Working Group
For coordination on APIs for sensors and actuators.
Decentralized Identifier Working Group
For coordination on identity management and information lifecycle.
Web & Networks Interest Group
For collaboration on networking and computing technologies on the edge and in the cloud when exposing interactions between Things.
Spatial Data on the Web Working Group
For collaboration on geolocation, in conjunction with the Open Geospatial Consortium.
Accessible Platform Architectures Working Group
In addition to horizontal review, coordination on impact of WoT technologies on accessibility, and support for new capabilities that help leverage WoT connectivity and sensor networks for accessibility support in public and private spaces is needed.
Privacy Interest Group
In addition to horizontal review, during development of deliverables such as discovery and information lifecycle that require the development of a privacy-preserving architecture, close technical collaboration with the Privacy Interest Group will be needed.
Schema Extensions for IoT Community Group
For collaboration on extensions to Schema.org for IoT use cases.
Autonomous Agents on the Web Community Group
For collaboration on application of Web of Things in Agent-based systems in the Web.

External Organizations

To succeed in establishing inter-platform standards, W3C needs to coordinate with IoT alliances and standards development organizations. A longer list is available on the Interest Group wiki that includes cooperations partners from former Web of Things charters.

List of active and new liaisons:

OPC Foundation
For coordination on the development of the OPC UA binding for the W3C Web of Things. A formal agreement between the OPC Foundation and the W3C is being considered to establish an official relationship.
ECHONET Consortium
For collaboration on integrating ECHONET Consortium based platforms within the Web of Things, including platform metadata and approaches for enabling semantic interoperability, and end to end security across platforms.
Industrial Digital Twin Association
For coordination on the use of TDs and bindings in the Asset Interface Description (AID) submodel for the Asset Administration (AAS) specification. Additionally, the AAS submodels can be used for Digital Nameplate (DNP) and Product Carbon Footprint (PCF) to form the Digital Product Passport (DPP) of products that the European Commission is demanding each product to supply (DPP4.0). Also see the related GitHub comment.
For coordination on the development of the BACnet (ASHRAE 135-2020) binding for the W3C Web of Things .
Coordinate common interests related to Internet of Things and Web of Things, e.g., issues such as serialization, security, and trustworthiness.
IRTF Thing to Thing Research Group
For coordination of matters of mutual interest in relation to the Web of Things, such as data modelling, discovery, directory services, and IoT semantics.
Connectivity Standards Alliance (CSA)
To coordinate smart home use cases and to develop a potential Matter binding.
One Data Model
For coordination of Semantic Definition Format (SDF) with the Thing Description.
Open Geospatial Consortium (OGC)
To coordinate geolocation use cases and potential geo-based definitions for Thing Models and Thing Descriptions.
To coordinate retail use cases and show case in PlugFests.
For collaboration and coordination of the technical realization of the use of ECLASS in the W3C Thing Description.
Coordinating smart city and digital twin use cases and aligning terminology definitions.


To be successful, this Working Group is expected to have 6 or more active participants for its duration, including representatives from the key implementors of this specification, and active Editors and Test Leads for each specification. The Chairs, specification Editors, and Test Leads are expected to contribute half of a working day per week towards the Working Group. There is no minimum requirement for other Participants.

The group encourages questions, comments and issues on its public mailing lists and document repositories, as described in Communication.

The group also welcomes non-Members to contribute technical submissions for consideration upon their agreement to the terms of the W3C Patent Policy.

Participants in the group are required (by the W3C Process) to follow the W3C Code of Ethics and Professional Conduct.


Technical discussions for this Working Group are conducted in public: the meeting minutes from teleconference and face-to-face meetings will be archived for public review, and technical discussions and issue tracking will be conducted in a manner that can be both read and written to by the general public. Working Drafts and Editor's Drafts of specifications will be developed in public repositories and may permit direct public contribution requests. The meetings themselves are not open to public participation, however.

Information about the group (including details about deliverables, issues, actions, status, participants, and meetings) will be available from the Web of Things (WoT) Working Group home page.

Most Web of Things (WoT) Working Group teleconferences will focus on discussion of particular specifications, and will be conducted on an as-needed basis. However, one teleconference will be held weekly to coordinate activities among the task forces responsible for each specification.

This group primarily conducts its technical work on GitHub issues, using a main repository for general topics and more specific repositories for individual specifications. The public is invited to review, discuss and contribute to this work.

The group may use a Member-confidential mailing list for administrative purposes and, at the discretion of the Chairs and members of the group, for member-only discussions in special cases when a participant requests such a discussion.

Decision Policy

This group will seek to make decisions through consensus and due process, per the W3C Process Document (section 5.2.1, Consensus). Typically, an editor or other participant makes an initial proposal, which is then refined in discussion with members of the group and other reviewers, and consensus emerges with little formal voting being required.

However, if a decision is necessary for timely progress and consensus is not achieved after careful consideration of the range of views presented, the Chairs may call for a group vote and record a decision along with any objections.

To afford asynchronous decisions and organizational deliberation, resolutions both proposed and taken in a face-to-face meeting or teleconference will be considered provisional. A call for consensus (CfC) will be issued for all such resolutions (via email) with a response period from 5 to 10 working days, depending on the Chairs' evaluation of the group consensus on the issue. If no objections are raised by the end of the response period, the resolution will be considered to have consensus as a resolution of the Working Group.

In some cases, resolutions can be announced and proposed in advance, by circulating an email to the group with concrete proposed text for the resolution. In these cases, the announcement can be considered the call for consensus (CfC) and when the resolution is made by the group, it can be considered final, at the discretion of the Chairs, if sufficient time (5 to 10 working days, at the discretion of the Chairs, as above) has been allowed for asynchronous input. This process will be followed especially for publication decisions which are then effective immediately.

All decisions made by the group should be considered resolved unless and until new information becomes available or unless reopened at the discretion of the Chairs or the Director.

This charter is written in accordance with the W3C Process Document (Section 5.2.3, Deciding by Vote) and includes no voting procedures beyond what the Process Document requires.

Patent Policy

This Working Group operates under the W3C Patent Policy (Version of 15 September 2020). To promote the widest adoption of Web standards, W3C seeks to issue Web specifications that can be implemented, according to this policy, on a Royalty-Free basis. For more information about disclosure obligations for this group, please see the licensing information.


This Working Group will use the W3C Software and Document license for all its deliverables.

About this Charter

This charter has been created according to section 3.4 of the Process Document. In the event of a conflict between this document or the provisions of any charter and the W3C Process, the W3C Process shall take precedence.

Charter History

The following table lists details of all changes from the initial charter, per the W3C Process Document (section 4.3, Advisory Committee Review of a Charter):

Charter Period Start Date End Date Changes
Initial Charter 27 December 2016 31 December 2018
Charter Extension 30 June 2019 Removed staff contact Yingyong Chen
Chair update Matthias Kovatsch changed his affiliation and re-appointed as co-Chair on 13 February 2019.
Chair update Kazuo Kajimoto stepped down as co-Chair on 4 April 2019.
Charter Extension 31 December 2019 Charter period extended till 31 December 2019
Charter Extension 31 January 2020 Charter period extended till 31 January 2020
Rechartered 31 January 2020 31 January 2022

New charter. Deliverables include updates to existing documents (Thing Description 1.1 and Architecture 1.1), extensions to existing documents (Thing Description 2.0) and new deliverables (Interoperability Profiles and Discovery)

Charter Extension 31 May 2022 Charter period extended till 31 May 2022
Charter Extension 31 July 2022 Charter period extended till 31 July 2022
Rechartered 28 July 2022 31 January 2023

New charter: Charter period extended until 31 January 2023; Switch to the Patent Policy 2020.

Charter Extension 31 July 2023 Charter period extended until 31 July 2023
Charter Extension 30 Sepbember 2023 Charter period extended until 30 September 2023
Rechartered 3 October 2023 2 October 2025
  • New charter.
  • Added Michael Koster to the co-Chairs.
  • Removed Team Contact, Dave Raggett.
  • Added further clarification on the motivation and background.
  • Simplified the description on the scope.
  • Updated the descriptions on the normative deliverables: Architecture (Update), Discovery (Update), Thing Description (Update), Profile and Profile (Update).
  • Updated the list of the coordination on W3C groups and external standardization organizations based on the recent situation.

Change log

Changes to this document are documented in this section.