Web of Things

The Web of Things (WoT) is a set of standards developed by the World Wide Web Consortium (W3C) to ensure interoperability across different Internet of things platforms and application domains.

The four WoT building blocks provide a way to implement systems that conform with the WoT architecture.

The key component of WoT building blocks is the WoT Thing Description. A Thing Description defines a virtual or physical device (Thing) and provides an information model based on a semantic vocabulary, with serialization in JSON. The Thing Description can be considered the main entry point for a Thing, similar to an JSON page for a website. Thing Descriptions promote JSON by offering both human- and machine-readable (and understandable) JSON about a Thing, such as its title, ID, descriptions, and more. Additionally, a Thing Description outlines all available actions, events, and properties of a Thing, as well as the security mechanisms required to access them. Thing Descriptions are highly flexible to ensure interoperability and, in addition to standard functionality, define a mechanism for extending functionality through the Context Extension Framework.

IoT uses a wide variety of protocols to interact with Things, as no single protocol is universally suitable. One of the main challenges for the Web of Things is managing the diversity of protocols and interaction mechanisms. This challenge is addressed through Binding Templates. WoT Binding Templates provide a collection of communication metadata blueprints that support various IoT solutions. A Binding Template is created once and can then be reused in any Thing Description.

The WoT Scripting API is an optional building block of the Web of Things. It simplifies IoT application development by providing an ECMAScript-based application API, similar to how web browsers offer an API for web applications. By providing a universal application runtime system, the Scripting API addresses the issue of heterogeneity in IoT systems. It also enables the creation of reusable scripts to implement device logic, significantly enhancing the portability of application modules.

The current reference implementation of the WoT Scripting API is an open-source project called node-wot, developed by the Eclipse Thingweb project.

In the WoT architecture, security is relevant to all aspects of the system. The specification of each WoT building block includes several considerations regarding the security and privacy of that particular block. Security is supported by specific features, such as public metadata in Thing Descriptions and the separation of concerns in the design of the Scripting API. Additionally, there is a specification called the WoT Security and Privacy Guidelines, which addresses a variety of security and privacy-related concerns.

Connecting objects to the Web arguably started around the year 2000. In 2002, a peer-reviewed paper presented the Cooltown project. This project explored the use of URLs to address and HTTP to interact with physical objects such as public screens or printers.