Mozilla has added support for the Web Serial API to Firefox on desktop with the release of Firefox 151. APIs enable browsers to communicate directly with hardware devices such as microcontrollers, development boards, and other serial-connected devices without the need for additional software.
This update brings Firefox closer to feature parity with Chromium-based browsers, which have supported Web Serials for several years. Mozilla sees this change as primarily useful to developers, manufacturers, teachers, and embedded device communities rather than the general user base.
What does Web Serial API enable in Firefox 151
Web Serial enables web pages to connect and communicate with hardware devices over a serial connection. Common uses include programming microcontrollers directly from the browser, configuring development boards through web-based tools, reading sensor data in web apps, and updating firmware on embedded devices.
Previously, many of these tasks required users to use a Chrome or Chromium-based browser, as Web Serial was not available in Gecko. However, with Firefox 151, these workflows are now possible in Firefox without additional setup for multiple projects.
Adafruit collaboration brings browser-based hardware workflows to Firefox
Mozilla is launching the feature in collaboration with Adafruit, the open-source hardware community known for CircuitPython, programmable microcontrollers, and education-focused electronics kits. Adafruit’s browser-based hardware workflows, including its WebSerial ESPTool, now work directly in Firefox.
Users can experiment with projects involving CircuitPython programming, board flashing, sensor input, and microcontroller communication without leaving the browser or installing dedicated client software.
Mozilla has published a detailed engineering post on Hacks.mozilla.org for developers interested in implementation details of Web Serial support in Gecko.
Availability of Web Serial in Firefox 151
Web Serial support now available Firefox 151 on desktop. Mozilla has not announced whether the API will be added to Firefox on Android or iOS, where browser engine restrictions on iOS limit how Web Serial can be implemented, even if Mozilla decides to include it.
The update also adds other features to Firefox 151, like VPN location selection, expanded language support for Shake to Summarize, and a one-click private browsing reset button.
