Retell AI

Retell AI — Technical Overview

Retell AI is a voice AI orchestration platform purpose-built for automating inbound and outbound phone call workflows at scale. It supports multiple LLM backends — including OpenAI GPT, Anthropic Claude, Google Gemini, and custom LLMs — giving developers flexibility in model selection without being locked into a single provider.

Key architectural highlights:

• ~600ms end-to-end voice latency, enabling natural, real-time conversational experiences
• 95.7% workflow accuracy in independent benchmarking
• REST API for programmatic agent creation, call management, and analytics
• No-code drag-and-drop agent builder alongside full API access, supporting both low-code and code-first workflows
• On-premises / self-hosted deployment option for data-sensitive environments
• Enterprise-grade compliance: HIPAA, SOC2 Type II, GDPR, and ISO 27001 certified
• AI Quality Assurance capable of analyzing up to 100% of call volume automatically
• Built-in outbound campaign dialer for high-volume calling operations

Integrations: Make, n8n, Twilio, Vonage, Telnyx, Go High Level, HubSpot, and SIP trunking.

Pricing: Usage-based at $0.07–$0.31/min for AI Voice Agents; $0.002+/msg for AI Chat Agents. Pay-as-you-go with $10 free credits at signup. Enterprise custom pricing available. No annual contract required.