Web Bluetooth is an API that enables interaction with Bluetooth devices through web browsers.
Until the advent of Web Bluetooth, users could only interact with Bluetooth devices through native apps. Interaction through browsers is a key part of the physical web that adds many possibilities for device interaction.
By serving up a URL to local mobile devices via Web Bluetooth, a device embedded in something as simple as a poster becomes a part of the physical web. The physical web is an unobtrusive way to offer mobile users a way to interact with physical things that are equipped with the technology.
Web Bluetooth has been compared to QR codes. Like QR, these simple Bluetooth LE transmitters present a small amount of information and a URL. This information is broadcast by Bluetooth LE and connection to the Web Bluetooth API enables further control.
An example might be a web enabled vending machine. The machine would a message broadcast by Bluetooth LE the reads, “Ice cold drinks for sale here. http://fakeurltobuy.drink.” The user would click on the URL to leave the physical web for the traditional web, interacting through the webpage to select the drink and pay for it. Drones have already been controlled by Web Bluetooth, too.
Google is a proponent of Web Bluetooth and the physical web. Chrome has supported the physical web and Web Bluetooth, to some degree, since 2016.