DRAFT Web of Things Working Group Charter

The mission of the Web of Things Working Group is to maintain and extend the family of WoT deliverables with new functionalities to support desired use cases. This work supports the overarching mission of the Web of Things to counteract fragmentation in the Internet of Things (IoT) by providing building blocks that enable seamless integration of devices and services across the IoT ecosystem.

Join the Web of Things Working Group.

This proposed charter is available on GitHub. Feel free to raise issues.

Charter Status See the group status page and detailed change history.
Start date [dd monthname 2026] (date of the "Call for Participation", when the charter is approved)
End date [dd monthname 2028] (Start date + 2 years)
Chairs Sebastian Kaebisch (Siemens) and Michael Koster (Invited Expert)
Team Contacts Dave Raggett (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, usually no more than 3 per year.

Motivation and Background

In recent years, the Web of Things (WoT) Working Group has developed a set of deliverables that address interoperability challenges in the IoT. These deliverables define standardized building blocks, such as the WoT Thing Description, WoT Discovery, and WoT Scripting API, which simplify IoT device on-boarding into target systems and applications, as well as IoT application development, by using well-established Web technologies. The WoT technology has already been deployed in production and is being increasingly adopted by other SDOs.

Newcomers are encouraged to read the Web of Things in a Nutshell documentation where they will find a technical overview of how the various existing deliverables relate to one another.

This new charter adds new work to cover additional features and to address emerging developments such as physical AI.

Scope

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

Increase Descriptiveness of WoT Thing Descriptions:
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.
WoT Bindings & Registry:
The WG will publish a set of protocol bindings that already have stable Editor’s Draft status from the previous WoT charter and will develop new ones. In addition, the Working Group will develop and maintain a registry of WoT bindings that records communication protocol bindings from W3C and external sources.
Update and Refactor Existing Deliverables:
The WG will add new features, maintain and refine the current deliverables, address issues identified during implementation, and reorganize material between documents as appropriate. While this work is not limited to backward‑compatible updates, great care will be taken to minimize the impact on existing implementations.
Developer Guidance:
The WG will develop developer guidance to support developers in designing WoT‑based applications, including best practices, tooling, and examples.
Web of Things Sub-Protocols:
The WG may develop sub‑protocols, for example based on WebSockets, that are specifically designed for the Web of Things and can be used as interfaces for IoT devices or services.

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.

Deliverables

Updated document status is available on the group publication status page.

Draft state indicates the state of the deliverable at the time of the charter approval. Expected completion indicates when the deliverable is projected to become a Recommendation, or otherwise reach a stable state.

Normative Specifications

The Working Group will deliver the following W3C normative specifications:

WoT Thing Description 2.0

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: FPWD

Expected CR Transition:Q4 2027

Expected PR Transition:Q2 2028

Expected REC Transition:June 2028

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.

Registries

To enhance interoperability implementation, the WoT Working Group develops and maintains registries for WoT Bindings.

WoT Binding Registry

Defines a registry of WoT bindings that make it possible to have a record of the different communication protocol bindings. Additionally, it sets the rules that govern this registry to guarantee a quality standard, long lifecycle and ease of use for the developers.

Draft state: Draft Registry

Expected completion:Q1 2027

Tentative Deliverables

Depending on the incubation progress, interest from multiple implementers, and the consensus of the Group participants, the Working Group may adopt the following documents as Rec-track

WoT Thing Protocol

This document defines HTTP and WebSocket sub-protocols for monitoring and controlling connected devices over the World Wide Web. The WoT Thing Protocol is intended as a dedicated protocol for the Web of Things, to enable a WoT Consumer to communicate with one or more WoT Things over an HTTP REST API and/or WebSocket connection.

Draft state: Draft Community Group Report

Informative Specifications

Other non-normative documents may be created or updated such as:

WoT Scripting API

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 Thing Description 2.0 specification. Besides these efforts, alignment with the WoT Discovery specification will be the main topic.

Draft state: Group Note

Expected completion:Q3 2027

WoT Use Cases and Requirements

The work will continuously maintain WoT use cases and requirements in accordance with the WoT Thing Description 2.0 specification.

Draft state: Group Note

Expected completion:Q3 2027

WoT Primer and Best Practice

Document supporting developers in designing WoT‑based applications, including the combination of AI techniques and tooling (e.g, AI Agents and MCP).

Draft state:No draft

Expected completion:Q4 2027

WoT HTTP Binding

Official WoT binding for HTTP

Draft state: Editors Draft

Expected completion:Q4 2026

WoT MQTT Binding

Official WoT binding for MQTT

Draft state: Editors Draft

Expected completion:Q4 2026

WoT Modbus Binding

Official WoT binding for Modbus

Draft state: Editors Draft

Expected completion:Q4 2026

WoT BACnet Binding

Official WoT binding for BACnet

Draft state: Editors Draft

Expected completion:Q4 2026

WoT CoAP Binding

Official WoT binding for CoAP

Draft state: Editors Draft

Expected completion:Q4 2026

WoT PROFINET Binding

Official WoT binding for PROFINET

Draft state: Editors Draft

Expected completion:Q4 2026

WoT LoRaWAN Binding

Official WoT binding for LoRaWAN

Draft state:No Draft

Expected completion:Q4 2026

Other Deliverables

Other non-normative documents may be created or updated such as:

  • Test suite and implementation report for the WoT Thing Description 2.0 specification
  • Test reports for the bindings documents mentioned above
  • Tooling for specification and resource generation
  • Update semantic artefacts for WoT Thing Description 2.0

Timeline

  • June 2026: First teleconference
  • July 2026: Initial contributions for Binding Registry entries
  • October 2026: First face-to-face meeting (TPAC 2026, Dublin, Ireland)
  • Q4 2026: FPWD of WoT Thing Protocol
  • Q4 2026: Publication of HTTP Binding as a Note
  • Q4 2026: Publication of MQTT Binding as a Note
  • Q4 2026: Publication of Modbus Binding as a Note
  • Q4 2026: Publication of BACnet Binding as a Note
  • Q4 2026: Publication of CoAP Binding as a Note
  • Q4 2026: Publication of PROFINET Binding as a Note
  • Q4 2026: Publication of LoRaWAN Binding as a Note
  • Q1 2027: WD of Thing Description 2.0
  • Q1 2027: Publication of Binding Registry as a Note
  • Q3 2027: Updated publication of Scripting API as a Note
  • Q3 2027: Updated publication of Use Cases and Requirements as a Note
  • Q4 2027: Publication of Primer and Best Practice as a Note
  • Q4 2027: CR Transition for Thing Description 2.0
  • June 2028: REC Transition for Thing Description 2.0

Success Criteria

TODO: Needs updating based on Success Criteria in previous charter

In order to advance beyond Candidate 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. In order to advance beyond Candidate Recommendation, each normative specification must have an open test suite of every feature defined in the specification.

There should be testing plans for each specification, starting from the earliest drafts.

Consider adopting a healthy testing policy, such as: To promote interoperability, all changes made to specifications in Candidate Recommendation or to features that have deployed implementations should have tests. Testing efforts should be conducted via the Web Platform Tests project.

Each specification should contain separate sections detailing all known security and privacy implications for implementers, Web authors, and users.

For specifications of technologies that directly impact user experience, such as content technologies, as well as protocols and APIs which impact content: 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.

This group is expected to be guided by the following documents:

Coordination

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:

In addition to the above catch-all reference to horizontal review which includes accessibility review, please check with chairs and staff contacts of the Accessible Platform Architectures Working Group to determine if an additional liaison statement with more specific information about concrete review issues is needed in the list below.

W3C Groups

Web & AI Interest Group
tbd
Autonomous Agents on the Web Community Group
tbd
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.
Web Thing Protocol Community Group
For the incubation of a common protocol for communicating with connected devices over the web, and handing off specifications to the WoT Working Group for formal recommendation track standardization.
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.

Note: Do not list horizontal groups here, only specific WGs relevant to your work.

Note: Do not bury normative text inside the liaison section. Instead, put it in the scope section.

External Organizations

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.
ASHRAE
For coordination on the development of the BACnet (ASHRAE 135-2020) binding for the W3C Web of Things .
IETF
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.
Conexxus
To coordinate retail use cases and show case in PlugFests.
ECLASS
For collaboration and coordination of the technical realization of the use of ECLASS in the W3C Thing Description.
ITU-T
Coordinating smart city and digital twin use cases and aligning terminology definitions.
IEC/SC 3D
Coordination of usage of the IEC Common Data Dictionary (CDD) vocabulary with WoT Thing Descriptions.

Participation

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-participants to make technical contributions for ongoing work, provided they agree to the terms of the W3C Patent Policy.

The Chairs should periodically look through the non-W3C-Member contributors to the Working Group or the [name of an associated Community Group, if any] and consider whether each one should be invited to participate as an Invited Expert. If a non-W3C-Member contributor would like to participate in meetings, they are encouraged to apply to be an Invited Expert.

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

Communication

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 WoT Working Group home page.

Most WoT Working Group teleconferences will focus on discussion of particular specifications, and will be conducted on an as-needed basis.

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-only 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

TODO: Needs updating based on Decision Policy from previous charter

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, any resolution (including publication decisions) taken in a face-to-face meeting or teleconference will be considered provisional. A call for consensus (CfC) will be issued for all resolutions (for example, via email, GitHub issue or web-based survey), with a response period from [pick a duration within:] one week to 10 working days, depending on the chair's 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.

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.

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 May 2025). 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.

Licensing

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

Note:Display this table and update it when appropriate. Requirements for charter extension history are documented in the Charter Guidebook (section 4).

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.
Chair update Michael McCool stepped down as co-Chair on 8 May 2025.
Rechartered [dd monthname yyyy] [dd monthname yyyy]

[description of change to charter, with link to new deliverable item in charter] Note: use the class new for all new deliverables, for ease of recognition.

Change log

Changes to this document are documented in this section.