Firefox can now connect directly to microcontrollers, development boards, 3D printers, power meters, and other serial-connected hardware from the web. Starting in Firefox 151 for Desktop, support for the Web Serial API allows web applications to communicate with compatible devices without requiring native software.

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Ports are allowed on a per-site and per-port basis. The Web Serial API requires websites to call navigator.serial.requestPort(), which lets the user choose which port to allow access to, or disallow all access entirely. This means websites do not receive a list of connected devices and there is no useful fingerprinting information outside of the port the user selects.

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While Web Serial still resides in the Web Incubator Community Group (WICG), we’re optimistic there’s a path to standardization given its scope and long-running incubation. We are pursuing standardizing the Web Serial API in the WHATWG in a new Workstream proposal and are excited to work with ecosystem partners and standards bodies to help shape access to peripherals on the web.