The best alternatives to Sat2.io are ChangeTip, Chain Networking, and Bitwala legacy. If these 3 options don't work for you, we've listed a few more alternatives below.
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Universal-2 by AssemblyAI— Speech-to-Text API for conversational data
Bitsms allows you to send Bitcoin via SMS, without an Internet connection. It is not a wallet. Instead, it is an SMS to Bitcoin relay where you sign a transaction in your wallet and text it to this number.