Retell AI

Retell AI is a platform for building and deploying AI voice agents that handle phone calls, answering inbound calls, making outbound calls, booking appointments, qualifying leads, and transferring calls to humans when needed. It delivers roughly 600ms latency conversations with natural turn-taking, a drag-and-drop workflow builder with real-time function calling for appointments and payments, and streaming RAG technology that auto-syncs with website content for knowledge integration. Retell supports batch calling, branded caller ID, verified phone numbers, and SIP trunking, with post-call analysis, AI quality assurance, and 100% call transcription for monitoring. It integrates with Twilio, Vonage, Make, HubSpot, and n8n, and is HIPAA, SOC2 Type II, and GDPR compliant with SSO and data redaction support. New users get $10 of free usage after signup, with enterprise pricing available by contacting sales.