Does Retell work with my existing phone number?

Yes. Retell supports SIP trunking, allowing you to connect and use your existing business phone numbers and telephony infrastructure.

Can the AI transfer calls to a human agent?

Yes. The platform supports agentic human handoffs where the AI can brief a human, confirm readiness, and seamlessly transfer the call.

What is the core technology stack behind the voice agent?

It uses a proprietary orchestration layer combining real-time ASR, an LLM for conversation management and function calling, and a TTS engine optimized for low latency (~600ms). It also includes a custom turn-taking model.

How does the AI Quality Assurance work?

It transcribes 100% of calls and uses AI to analyze transcripts for compliance, sentiment, and issue patterns, surfacing insights across your entire call volume rather than a manual sample.

What's the difference between the 'Pay as you go' and 'Enterprise' plans?

Pay-as-you-go has per-minute pricing with full platform access but community support. Enterprise offers custom volume pricing, dedicated support, SLAs, advanced security features like custom SSO and on-prem deployment.

Directory/Automation/AI Assistants/Retell AI

Retell AI

Retell AI is a conversational AI platform for building, deploying, and managing voice AI agents that handle phone calls. It provides a no-code studio for designing complex call flows with drag-and-drop tools, integrating with telephony systems (SIP, Twilio, Vonage), and connecting to CRMs, calendars, and knowledge bases. The platform is built for production call centers, handling inbound/outbound calls, lead qualification, appointment setting, customer service, and dispatch, with features like agentic handoffs, batch campaigns, and real-time monitoring. The core tech features proprietary voice AI orchestration with low latency (~600ms), ultra-realistic TTS, and turn-taking models. It supports multilingual conversations, compliance (HIPAA, SOC2, GDPR), and enterprise security. Developers can use APIs, SDKs, and CLI for deep control, while business teams manage agents via the dashboard.

Automation

Visit website

Added on

Sep 22, 2026

Voice Agent PlatformNo-Code BuilderBatch CallingAI QAReal-Time AnalyticsHIPAA CompliantSIP TrunkingCustom LLM Support

Product information

Everything worth knowing about Retell AI

The complete picture — from everyday features to the technical detail builders and IT folks dig for.

Core features

What it actually does

Drag-and-Drop Conversation Builder

Design complex call flows visually on a canvas, adding functions, integrations, transfers, DTMF, SMS, and custom logic.

AI Voice Agent & Chat Agent Deployment

Deploy AI agents for phone calls, web chat, and SMS from a single platform.

Call Transfer & Human Handoff

Seamlessly switch conversations between AI and human agents, with AI briefing the human on context.

Post-Call Analysis & AI Quality Assurance

QA up to 100% of calls, transcribe conversations, and analyze metrics to improve performance at scale.

Batch Calling for Outbound Campaigns

Run high-volume outbound campaigns with scheduling, pacing, retries, and voicemail detection.

Technical capabilities

Proprietary Low-Latency Voice Orchestration

Achieves ~600ms latency with proprietary turn-taking models for human-like conversation flow.

SIP Trunking Integration

Connect to custom telephony providers and existing phone numbers via SIP trunking.

Must watch videos

How to Build Smarter AI Voice Agents in Minutes with Retell AI Conductor

7:00

Tutorial7:00

How to Build Smarter AI Voice Agents in Minutes with Retell AI Conductor

Build and improve AI voice agents faster with Retell AI Conductor. Create, test, analyze, and optimize your voice agents from one contextual AI assistant. Retell AI lets you build and optimize AI voice agents with Conductor, without jumping between tools. Try Retell AI free → https://dashboard.retellai.com/?utm_source=youtube&utm_medium=organic_video&utm_campaign=conductor_education&utm_content=description_cta&utm_term=ai_voice_agent In this tutorial: * Build an AI voice agent from a prompt with Retell AI Conductor * Optimize AI voice agent prompts, conversation flows, and latency * Create simulation tests and test real edge cases * Analyze failed calls and production call history * Build voice agent analytics dashboards and compare agent performance Timestamps 0:00 - Retell AI Conductor overview 0:40 - Open Conductor in the Retell dashboard 0:50 - Build an AI voice agent from a prompt 1:45 - Plan your agent and optimize latency 2:08 - Improve conversation flows with sub-agents 3:03 - Create and run AI voice agent simulation tests 3:50 - Analyze failed calls and call history 4:25 - Build an analytics dashboard with Conductor 6:12 - Get guided help with Retell features 7:03 - Conductor shortcuts and contextual actions 8:08 - Conductor best practices and next steps Resources * Conductor documentation → https://docs.retellai.com/conductor/overview?utm_source=youtube&utm_medium=organic_video&utm_campaign=conductor_education&utm_content=description_docs&utm_term=ai_voice_agent * What is an AI voice agent? → https://www.retellai.com/blog/what-is-an-ai-voice-agent?utm_source=youtube&utm_medium=organic_video&utm_campaign=conductor_education&utm_content=description_blog&utm_term=ai_voice_agent * Community → https://community.retellai.com/ Related * Retell AI Conductor: The Copilot for Building Voice Agents → https://www.youtube.com/watch?v=gQGNOyHLXxk * Conductor is Everywhere: AI Voice Agent Observability on Every Page → https://www.youtube.com/watch?v=Ym_nTGIs804 #aivoiceagent #voiceai #retellai

Conductor is Everywhere: AI Voice Agent Observability on Every Page

0:51

Tutorial0:51

Conductor is Everywhere: AI Voice Agent Observability on Every Page

Conductor is now available at every stage of your Retell agent's lifecycle. AI voice agent observability is now available on every page. Ask anything, debug faster, and ship better voice agents. Meet Conductor is Everywhere, the new way to monitor, debug, and improve your AI voice agents in Retell AI. No more digging through Call History, Analytics, and AI QA tabs. Just ask in plain language. Conductor can filter calls, identify why calls fail, explain metric drops, and build dashboard charts for you. In this 51-second launch video, see how Conductor works where you already work. It understands your page context, reads transcripts and workflow nodes, summarizes AI QA cohorts, and gives you recommended next steps with your approval. No production changes happen without you. Perfect for builders, ops teams, and QA leads reviewing high volumes of AI calling agent calls. What you'll see: 0:00 - Conductor is now analytical 0:12 - Ask "Why are calls failing?" and the dashboard auto-filters 0:24 - 35 calls identified + root-cause summary 0:39 - Select unsuccessful calls + Improve using failures 0:50 - Conductor is Everywhere on Retell AI Try Retell AI: https://www.retellai.com/?utm_source=youtube&utm_medium=video&utm_campaign=conductor_is_everywhere Read the launch blog: http://retell.com/blog/conductor-is-everywhere/ #RetellAI #AIVoiceAgent #ConductorIsEverywhere

Retell AI Workflows: Orchestrate Your Voice Agent

0:57

Tutorial0:57

Retell AI Workflows: Orchestrate Your Voice Agent

Try Retell Workflows now: https://docs.retellai.com/integrations/overview#run-tools-before-or-after-the-call-or-chat Learn how to use it: https://www.youtube.com/watch?v=qe9nx250-bs Join the Community • Retell Forum - https://community.retellai.com/ • Discord - https://discord.com/invite/Wrnu4aMZy7 Docs & Resources: • Retell AI Docs → https://docs.retellai.com/ Connect with Retell AI • LinkedIn - https://www.linkedin.com/company/retellai • Instagram - https://www.instagram.com/retell_ai/ • X - https://x.com/retellai About Retell Retell AI is an enterprise-grade voice AI platform for building intelligent phone agents that can handle real business calls. Developers and teams use Retell to build, test, deploy, and monitor AI voice agents that are fast, natural, and reliable.

Who uses it

Real use cases, no hype

AI Receptionist

Automate front-desk calls, handle inquiries, and route calls to the right department.

Lead Qualification

Score and qualify inbound/outbound leads automatically via voice conversation.

Appointment Setting

Check availability, book, confirm, and reschedule appointments in real-time.

AI Customer Service

Resolve routine support tickets, check order status, and answer FAQs 24/7.

Outbound Campaigns

Run high-volume outbound dialing for surveys, debt collection, or telemarketing.

Dispatch Service

Handle dispatch coordination and updates for logistics, field services, or emergency support.

What's great

Industry-leading low latency (~600ms) for natural conversation flow
No-code visual builder for complex call flows and workflows
Built-in outbound campaign and batch calling capabilities
Real-time live monitoring and human takeover during calls
Extensive integrations with CRMs, telephony (Twilio, Vonage), and automation tools

Technical strengths

Proprietary turn-taking model for more human-like interaction
100% call QA and transcription for full performance analytics
HIPAA, SOC2 Type II, GDPR compliant with enterprise-grade security features

Where it falls short

Per-minute pricing can become expensive at high call volumes without enterprise contract
Initial setup requires understanding of telephony concepts (SIP, IVR) for complex integrations
Free tier is limited; full feature unlock requires paid plan or enterprise deal

Technical limitations

Vendor lock-in risk due to proprietary orchestration and workflow engine
Advanced customization may require deep API/SDK usage beyond the no-code dashboard
Performance dependent on underlying LLM and TTS model choices

For technical folks

The deep-dive specs

FAQ

Includes technical Q&A

You can sign up, use the pre-built templates, and have a basic agent testing in under 15 minutes. Production deployment with full integration takes longer.