<p>Firefox 151 for desktop now supports the <a href="https://developer.mozilla.org/en-US/docs/Web/API/Web_Serial_API" target="_blank" rel="noopener nofollow">Web Serial API</a>, letting web apps talk directly to serial-connected hardware without any native software installed. That means microcontrollers, development boards, 3D printers, USB power meters, and similar devices can be accessed straight from the browser.</p>
<p>Mozilla worked with Adafruit to test and validate the implementation against real-world workflows. Adafruit’s browser-based tools — including the WebSerial ESPTool used to flash ESP32 boards — now work in Firefox. CircuitPython workflows on devices like Raspberry Pi Pico and LEGO hardware are supported as well.</p>
<h2>Security model</h2>
<p>Firefox won’t silently enumerate connected devices. Access requires an explicit user permission prompt, and the implementation uses add-on gating to prevent fingerprinting exposure. Enterprise deployments have Web Serial disabled by default, with policy controls available for IT administrators who want to manage access.</p>
<h2>Standardization</h2>
<p>Mozilla is also pushing to get the Web Serial API standardized through WHATWG. Chrome has supported the API for a while, so Firefox 151 closes a meaningful gap for makers, educators, and embedded-device communities who’ve been waiting to use browser-based hardware tools without switching browsers.</p>


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Firefox 151 adds support for the Web Serial API, enabling web apps to communicate directly with serial-connected hardware like microcontrollers, 3D printers, and development boards without native software. Mozilla collaborated with Adafruit to validate the implementation, which now supports tools like WebSerial ESPTool for ESP32 flashing and CircuitPython workflows on Raspberry Pi Pico and LEGO hardware. The security model requires explicit user permission and uses add-on gating to prevent fingerprinting. Enterprise deployments have the API disabled by default. Mozilla is also pushing for WHATWG standardization, closing a gap with Chrome that has supported the API for some time.

Firefox 151 adds Web Serial API support for hardware communication

<p>Nice to see Firefox finally adding Web Serial. I’ve had to switch browsers a few times just to flash boards and test hardware, so this removes a lot of unnecessary friction for makers and students.</p>


<p>Cool. Maybe WebMIDI is somewhere on the drawing board as well? Keeping my fingers crossed. 😉</p>
<p>EDIT: Actually… 😁 It seems I’ve been keeping my fingers crossed for so long without checking that it got implemented over 40 versions ago, in 108. 😅</p>
