I'm building a PWA with Nuxt.js that uses the Web Serial API to communicate with our proprietary hardware. It works as expected (i.e. the port will be available without user action the next time you load the web app unless the browser security is reset) on Windows 10/11 and macOS devices, but the device this application will be running on is a Raspberry Pi 4 running the latest stable Rasbian release. On the only two browsers I've found that can run on the Raspberry Pi and support the Web Serial API are Chromium and Vivaldi. In both of those browser, there is an issue remembering which port(s) the user has already allowed access to.
In Chromium, even a page refresh will cause the port permissions to reset, requiring the user grant access to the serial port again. In Vivaldi, the permissions can survive a page refresh, but restarting to browser will cause it to forget any prior port authorizations.
I have not been able to find any option to whitelist websites in the browser settings the way you can for some other security/privacy options, like you can with things like website clipboard access, nor any way to disable the security feature altogether.
This will be running on custom hardware that ships with the software, so there are no limitations to what can be modified to resolve or work around this. The device is touchscreen only, and the app will be running in a fullscreen kiosk mode at boot. There just needs to be some way to prevent the user from needing to select a port like /dev/s0 and grant the web app access to it every single time they turn the device on.
