The Web Serial API landed in Firefox 151, allowing you to connect directly to microcontrollers, dev boards, 3D printers, power meters, and other serial-connected hardware from the web.
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The Web Serial API landed in Firefox 151, allowing you to connect directly to microcontrollers, dev boards, 3D printers, power meters, and other serial-connected hardware from the web. Here's how it works:
See our announcement post for more detail, demos, and docs https://hacks.mozilla.org/2026/05/web-serial-support-in-firefox/
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The Web Serial API landed in Firefox 151, allowing you to connect directly to microcontrollers, dev boards, 3D printers, power meters, and other serial-connected hardware from the web. Here's how it works:
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The Web Serial API landed in Firefox 151, allowing you to connect directly to microcontrollers, dev boards, 3D printers, power meters, and other serial-connected hardware from the web. Here's how it works:
@firefoxwebdevs what motivated you to implement Web Serial API, after so many years of not implementing it? Also, is this an outlook for Web USB and/or Web Bluetooth?
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The Web Serial API landed in Firefox 151, allowing you to connect directly to microcontrollers, dev boards, 3D printers, power meters, and other serial-connected hardware from the web. Here's how it works:
@firefoxwebdevs so Web Serial is OK but WebHID and WebUSB are not? -
@firefoxwebdevs so Web Serial is OK but WebHID and WebUSB are not?
@hj what do you mean by 'ok' here?
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@hj what do you mean by 'ok' here?
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@firefoxwebdevs what motivated you to implement Web Serial API, after so many years of not implementing it? Also, is this an outlook for Web USB and/or Web Bluetooth?
@Schepp developer feedback, and finding a satisfactory flow that communicates the security and privacy implications.
This is the second API we've done this with, the other being WebMIDI. We're looking at other similar APIs one at a time.
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@hj Web Serial is the second API we've applied this new permission flow to, the other being WebMIDI. We'll continue to look at other APIs on an individual basis.
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@hj Web Serial is the second API we've applied this new permission flow to, the other being WebMIDI. We'll continue to look at other APIs on an individual basis.
@firefoxwebdevs I hope you implement at least WebHID because it's very popular and lack of support for it in Firefox just drives popularity of Electron and Chromium(-based browsers) -
@firefoxwebdevs I hope you implement at least WebHID because it's very popular and lack of support for it in Firefox just drives popularity of Electron and Chromium(-based browsers)
@hj which sites do you use that use it, or what are your use-cases for it as a developer?
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@hj which sites do you use that use it, or what are your use-cases for it as a developer?
@firefoxwebdevs something like https://usevia.app/ https://launcher.keychron.com/
Same idea as Web Serial, just different hardware API. Usecase is the same - controlling and configuring hardware.
VIA and Keychron Launcher let me configure my keyboard and mouse without having to download a windows-only "driver" and run it on wine with terrible results. -
@Schepp developer feedback, and finding a satisfactory flow that communicates the security and privacy implications.
This is the second API we've done this with, the other being WebMIDI. We're looking at other similar APIs one at a time.
@firefoxwebdevs @Schepp
What about restore GUI that follows the system?
Fix printing bugs.
Offer paginated view of a website.
Fix bugs.
Strip all viewers except Web page (no PDF).
Fix bugs.
Fix GUI.
Privacy.I do not want WebApps, or controlling serial or USB devices or MIDI via a web page.
I want a WEB BROWSER. Something that fetches webpages, renders HTML/CSS and allows disabling per item of content not from the domain.
Listen to real users! But it's nearly impossible to send feedback!
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@firefoxwebdevs @Schepp
What about restore GUI that follows the system?
Fix printing bugs.
Offer paginated view of a website.
Fix bugs.
Strip all viewers except Web page (no PDF).
Fix bugs.
Fix GUI.
Privacy.I do not want WebApps, or controlling serial or USB devices or MIDI via a web page.
I want a WEB BROWSER. Something that fetches webpages, renders HTML/CSS and allows disabling per item of content not from the domain.
Listen to real users! But it's nearly impossible to send feedback!
@firefoxwebdevs @Schepp
I write as someone that has developed software, uses real & USB based serial, various USB devices (MTP, Storage, Minidisc, camera, capture, audio), PDFs, built websites, desktop & embedded programs.
Every week there is new garbage program using the Web Browser instead of a sane GUI framework.
A web Browser is now a privacy leaking monster.
Firefox-bin 517.5 MiB one Tab!
That's obscene.
KATE 161.9
Okular with a giant PDF manual: 206 MiB. It's the Swiss Army Knife viewer. -
The Web Serial API landed in Firefox 151, allowing you to connect directly to microcontrollers, dev boards, 3D printers, power meters, and other serial-connected hardware from the web. Here's how it works:
Finally... When WebUSB so I would not need Chromium to configure keyboard?
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The Web Serial API landed in Firefox 151, allowing you to connect directly to microcontrollers, dev boards, 3D printers, power meters, and other serial-connected hardware from the web. Here's how it works:
@firefoxwebdevs
This is what we want!
Not stupid soccer widgets appearing without consent and AI Slop,
but actual features and improvements to the browser!!!You are on thin ice still but more of this and no bs please.
Maybe you might even stop alienating your userbase then
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Finally... When WebUSB so I would not need Chromium to configure keyboard?
@hrw @firefoxwebdevs
No they really need to focus on AI Slop and soccer and weather widget that appear without consent first -
The Web Serial API landed in Firefox 151, allowing you to connect directly to microcontrollers, dev boards, 3D printers, power meters, and other serial-connected hardware from the web. Here's how it works:
@firefoxwebdevs ok, this is actually great news.
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The Web Serial API landed in Firefox 151, allowing you to connect directly to microcontrollers, dev boards, 3D printers, power meters, and other serial-connected hardware from the web. Here's how it works:
@firefoxwebdevs not a security nightmare at all...
/s
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@firefoxwebdevs not a security nightmare at all...
/s
@tasket @firefoxwebdevs How exactly is it a security nightmare when it needs explicit user consent?
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@tasket @firefoxwebdevs How exactly is it a security nightmare when it needs explicit user consent?
@niutech How many users understand what is being asked of them?
How much will these prompts proliferate?
