Retell AI

Free tier

#1 AI Voice Agent Platform for Automating Phone Calls

Free tier available·All audiences·Powered by Multiple (OpenAI GPT, Anthropic Claude, Google Gemini, Custom LLM)·API available

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Key strengths

Low-latency (~600ms) voice AI orchestrationHigh workflow accuracy (95.7% in independent benchmark)No-code drag-and-drop agent builderEnterprise-grade compliance (HIPAA, SOC2 Type II, GDPR, ISO 27001)Outbound campaign dialer built-inAI Quality Assurance up to 100% of callsOn-premises deployment option

Free tier + paid plans

Self-hostable

Facts verified against retellai.com on Oct 5, 2026

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Retell AI — Developer Docs & Integration

Retell AI exposes a REST API for full programmatic control over agent configuration, call initiation, campaign management, and analytics retrieval. Developers can integrate Retell AI into existing stacks or build net-new voice automation pipelines.

Integration surface:

Telephony: Native integrations with Twilio, Vonage, Telnyx, and SIP trunking for BYOC (Bring Your Own Carrier) setups
Automation platforms: Make and n8n for workflow orchestration
CRM: HubSpot and Go High Level for lead and contact management
Custom LLM support: Connect your own LLM endpoint alongside hosted options (OpenAI GPT, Anthropic Claude, Google Gemini)

Deployment options:

Cloud-hosted (managed)
On-premises / self-hosted for organizations with strict data residency or compliance requirements

Compliance certifications available: HIPAA, SOC2 Type II, GDPR, ISO 27001 — relevant for enterprise procurement and security reviews.

Pricing model: Usage-based with no annual contract. $0.07–$0.31/min (Voice Agents); $0.002+/msg (Chat Agents). $10 free credits on signup. Enterprise tier available with custom pricing.

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