JsSIP VS linphone-android

There’s def web clients already out there. I’ve seen satchel, just haven’t come across an actively developed one.

Jssip is a neat library but not a client: https://jssip.net/

Twilio also has a web client.

Taking a cursory search of WebAssembly for voip shows some activity:

Webrtc is a little old and using webassembly to introduce other codecs isn’t entirely new or novel: https://cloudtweaks.com/2020/08/deep-customization-webrtc/

Blazer allows using webassembly to make calls from twilio: https://www.twilio.com/blog/making-phone-calls-from-blazor-w...

Another neat use for webassembly and audio is audio production say for podcasts with multiple callers that makes editing a bit easier. https://superpowered.com/js-wasm-overview

Noise cancellation and other dsp effects are something webassembly can meaningfully help with. https://news.ycombinator.com/item?id=30568164

https://github.com/onsip/SIP.js or https://github.com/versatica/JsSIP combined with a SIP server like Asterisk/FreePBX or Freeswitch/FusionPBX

Well I can tell you that any SIP program can do this, one that comes to mind is Linphone. But you do need a provider. Almost all providers deal with UDP. You might be able to find one that transmits over tcp but that’ll be a very small list. TCP isn’t reliable for VoIP, for media anyway. At best you’ll find one that encrypts the signaling over TLS, which is TCP. But audio, even if encrypted too, is done over UDP. You might have to use a provider that maybe provides WEBRTC. This utilizes VoIP over your browser, to put it simply.

Does Linphone (https://linphone.org/) not meet that need of cross platform (website claims versions for all major OS'es) and open source (https://gitlab.linphone.org/BC/public/linphone-desktop)?

Linphone is good.

Similarly, you can use any SIP (VoIP) provider (e.g. VOIPo Cloud), and configure the SIP account details in your native phone app. This way you will also be able to use a SIP softphone on your computer (e.g. LinPhone on Linux or Telephone on Mac), or even a real SIP phone in your home. Depending on your SIP plan you may or may not be able to make international calls this way.