Is texting back someone who called you TCPA-compliant?

Yes, and it's the foundation of the product: someone calling your business number expresses prior consent to be contacted back about that same need — exactly the frame the TCPA recognizes for responses initiated by the caller. The message stays in that frame: it answers the call, identifies your business and offers help — no unsolicited advertising, no list signup behind their back. Every send is timestamped and tied to the call that triggered it, so proof of consent exists for every text. And the moment the person says STOP, the opt-out registry blocks them within 24 h, permanently.