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Browser Diagnostics Web Serial serial port UART

WebSerial Test

Check Web Serial availability and optionally pick a port. Desktop Chromium primarily; no data is read or written.

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Interactive tool

Run the test

Runs in your browser

Checks Web Serial support (mainly desktop Chrome/Edge). Safari, Firefox, and most phones do not support it. You can open the port picker; this page does not read or write data.

No ports listed yet.

Checking Web Serial support…

Permission status

Checked in your browser. DeviceHub does not store permission grants.

  • Special permission Not required

Live results

Metrics update as you run the test. Nothing is uploaded.

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Waiting for interactive tool output…

Device information

Labels and capability details reported by your browser.

No device details yet.

Description

About WebSerial Test

Introduction

This page checks whether Web Serial exists and can open the port picker. Support is mainly desktop Chrome/Edge. The page does not read or write bytes on the port.

What this tool does

It reports API presence, lists ports previously allowed for this site when available, and can request a new port. It does not open a data session.

When to use it

Use it before debugging a serial web app on Chromium desktop.

How it works

Supported: Chrome/Edge on desktop over HTTPS. Unsupported: Safari, Firefox, and most mobile browsers. Why: serial port access is powerful and limited to a few engines. Permissions: you approve a port in the picker. Hardware: a USB-serial device if you use the picker. Expected: available/unsupported and an optional picker — no console traffic from this page.

Step-by-step instructions

  1. Open Web Serial Test in desktop Chrome or Edge.
  2. Read availability.
  3. Optionally request a port or cancel.

Common problems

Unsupported on Safari/Firefox/mobile is expected. Drivers must still work at the OS level for real apps.

Privacy explanation

No serial bytes are read or uploaded.

Runtime principles

Built for the browser

What happens when you run this test — without downloads or accounts.

  1. 01

    Runs in your browser

    WebSerial Test uses standard web APIs — no install, extension, or desktop app required.

  2. 02

    Reads what the browser allows

    Results come from events and capability signals the web platform exposes for this session.

  3. 03

    Private by default

    Input and diagnostic values stay in your browser session for display — nothing is sold as media.

Compatibility

Supported browsers

Expected support for modern engines. Individual APIs may still vary by device.

  • Chrome

    supported

    Latest stable

  • Firefox

    supported

    Latest stable

  • Safari

    supported

    Latest stable

  • Edge

    supported

    Latest stable

Devices

Supported devices

Hardware and form factors this browser test is designed to exercise.

  • Desktop browsers

    Chrome, Firefox, Safari, and Edge on Windows, macOS, Linux.

  • Laptops

    Reports identity and feature signals for the active session.

  • Phones & tablets

    Mobile browsers with web platform capability probes.

Privacy

Your data stays with you

WebSerial Test is built privacy-first. Diagnostics run in your browser session whenever web APIs allow.

Read our privacy policy

Troubleshooting

Common problems

Quick fixes before you dig into FAQs.

serial API missing
Web Serial targets Chromium on HTTPS; Safari and Firefox often lack it entirely.
Port not listed
Confirm USB-serial drivers, cable, and that another app is not exclusively locking the port.
Works in native terminal but not browser
Browser pickers expose only compatible ports; OS permissions and driver class still matter.

FAQ

Frequently asked questions

Structured answers for users and FAQ rich results.

Browse FAQs
Does this send data to my serial device?
No. It only checks support and may open the port picker.
What do browsers expose?
A Web Serial API and user-approved port picker in Chromium desktop.
What do they not expose?
Serial access in Safari/Firefox/most mobile browsers.
Which browsers work?
Primarily desktop Chrome and Edge.
Permissions or hardware?
Port approval in a prompt. A serial device is optional unless you use the picker.
What should I expect?
Available or unsupported, plus an optional picker with no data transfer.

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Release notes

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