For context, here are some similar services:

|| Service || FLOSS client || Notes ||
|| [[https://www.burnerapp.com/|Burner]] || No || Focused on being a "second number" for your phone. ||
|| [[https://www.line2.com/|Line2]] || No || ||
|| [[https://hushed.com/|Hushed]] || No || ||
|| [[https://voice.google.com|Google Voice]] || No || ||
|| [[http://www.coverme.ws/en/index.html|CoverMe]] || No || (it's not..super clear if this is a chat protocol with some sort of weird SMS glue or if it's a genuine bridge) ||
|| [[https://www.sideline.com/|Sideline]] || No || ||
|| [[https://www.textnow.com/|TextNow]] || No || ||
|| [[https://mysudo.com/|MySudo]] || No || ||
|| [[https://voip.ms|VoIP.ms]] || Yes (CSipSimple/[[https://f-droid.org/wiki/page/net.kourlas.voipms_sms|Voip.ms SMS]]) || ||
|| [[http://vitelity.com|Vitelity]] || Yes (SIP/XMPP) || ||