What Retell AI does
Retell AI is a developer platform for customer-facing voice and chat agents, combining speech, language models, telephony, knowledge, integrations, testing, and analytics.
Retell provides the orchestration layer for real-time voice and chat agents. Builders can choose models and voices, connect telephony, add knowledge and functions, simulate conversations, define transfers and guardrails, and inspect transcripts, analytics, and webhooks. Cost and behavior depend on each selected component.
Pay-as-you-go starts with free credits and currently lists AI voice agents at roughly $0.07 to $0.31 per minute and chat from $0.002 per AI message. Model, voice, telephony, knowledge, denoising, PII removal, QA, phone numbers, SMS, and concurrency can each add cost. Enterprise is custom.
A voice agent can mishear identity, disclose information, make an unauthorized promise, fail during an emergency, or violate consent and calling rules. Disclose automation where required, verify identity before account actions, minimize recording, configure redaction and retention, test adversarial and accessibility cases, offer immediate human transfer, and review legal requirements by jurisdiction.
How Retell AI works
A builder configures prompts, a language model, voice or speech-to-speech engine, phone or chat channel, knowledge sources, functions, transfer rules, and webhooks. During a call, Retell streams audio through speech and conversation components, invokes tools when configured, produces synthesized speech, and records analytics or transcripts according to settings. Humans monitor calls, handle escalation, and audit outcomes.
How to set up Retell AI
Define a permitted call
Document purpose, audience, consent and recording rules, prohibited actions, identity checks, escalation, hours, and success measures.
Build with least privilege
Choose a model and voice, provide narrow knowledge, use restricted tool credentials, and separate read actions from consequential writes.
Design failure paths
Add confirmation for names and amounts, silence and interruption handling, voicemail rules, human transfer, emergency language, and safe fallback responses.
Simulate difficult calls
Test accents, noise, latency, prompt injection, sensitive requests, repeated failure, accessibility, tool outages, and cost per completed outcome.
Launch gradually
Start with low-risk traffic, monitor transcripts and redaction, sample outcomes, track complaints and transfers, and keep a human shutdown owner.
Retell AI FAQs
How much does Retell AI cost?
Voice agents currently range from about $0.07 to $0.31 per minute before optional components; chat and enterprise pricing use separate rates.
Are failed calls billed?
Retell says failed connections are not billed, while connected voicemail time and silence or hold time can be billed while the agent is active.
Can Retell transfer to a person?
Yes. Transfer logic can hand a call to a human; the AI agent fee stops after transfer, though telephony charges can continue.
Is Retell automatically compliant for healthcare or calling laws?
No. Features and enterprise agreements can support a compliant deployment, but the customer must configure consent, contracts, access, retention, and workflows correctly.
Can voice agents take payments or change accounts safely?
Only with strong identity checks, scoped tools, confirmations, logging, limits, and human escalation. High-risk actions should not rely on conversational confidence alone.
Listing reviewed 2026-07-23. Product details and pricing can change; verify important terms on the provider's website.
Related Automation AI tools
Related AI guides
Reviews
Tell the community what you made, what worked, and what you wish you knew before starting.