retell-ai.md
name: Retell AI slug: retell-ai website: https://www.retellai.com/ type: commercial track: users category: voice-ai-agents subcategory: voice-agents status: active description: AI voice agent platform for building human-like conversational agents that handle phone calls autonomously with ~600ms latency pricing_model: usage-based founded_year: 2023 headquarters: San Francisco, CA last_verified: ‘2026-06-09’ confidence_score: 0.95 —
Overview
Retell AI is a 3rd-generation voice AI platform that enables businesses to build and deploy human-like conversational agents for phone call automation. The platform offers industry-leading ~600ms latency with advanced features including real-time function calling, drag-and-drop call flow design, streaming RAG integration, and AI-powered quality assurance. Retell powers autonomous voice agents for appointment booking, lead qualification, customer support, debt collection, and more. Notable customers include Pine Park Health (38% increase in scheduling NPS), SWTCH (50%+ reduction in support costs), and Medical Data Systems (~$280K monthly in AI-processed collections).
The Verdict
Who Should Use Retell AI?
Best For
- Healthcare practices automating appointment scheduling
- Sales teams needing AI-powered outbound calling
- Customer support teams wanting 24/7 coverage
- Debt collection agencies automating follow-ups
- Developers building custom voice agent solutions
- Teams already using Twilio or SIP infrastructure
Not Ideal For
- Enterprise with custom compliance needs (Enterprise plan required)
- Teams needing sub-200ms latency
- Non-English-primary markets (limited language support)
- High-volume operations on pay-as-you-go (costs scale up)
What's Great
- Industry-leading ~600ms latency for natural conversations
- Drag-and-drop agentic framework for call flows
- Real-time function calling and RAG integration
- AI-powered post-call quality assurance
- Pre-built templates to get started quickly
- Integrates with HubSpot, Salesforce, Twilio
- 4.8-star rating from 929 reviews
- $10 free credits to start testing
Watch Out For
- Usage costs add up quickly at scale ($0.07-$0.31/min)
- Concurrency beyond 20 calls costs $8/call/month extra
- Knowledge bases cost $8/month after first 10 free
- Custom SSO and MSA terms require Enterprise plan
- Phone number verification costs $10/month
Pricing
View all features & details
Voice Capabilities
- ~600ms response latency
- Natural human-like conversations
- Inbound and outbound calls
- Call transfer and warm handoff
- Voicemail detection
- Multi-language support
Agentic Framework
- Drag-and-drop call flow builder
- Real-time function calling
- Streaming RAG integration
- Pre-built agent templates
- Custom prompt engineering
- Dynamic conversation paths
Analytics & QA
- AI-powered quality assurance
- Call analytics and transcripts
- Performance monitoring
- Simulation testing
- Webhook notifications
- API access for custom reporting
Integrations
- HubSpot CRM
- Salesforce
- Twilio telephony
- Custom SIP trunks
- Webhooks and API
- Zapier automations
Use Cases
- Appointment scheduling
- Lead qualification
- Customer support
- Debt collection
- Outbound sales calls
- Surveys and feedback
Enterprise Features
- Unlimited concurrent calls
- Custom MSA/DPA terms
- Role-based access control
- Dedicated stable server
- Custom SSO configuration
- 24/7 omnichannel support
How It Compares
| Feature | Retell AI | Bland AI | Synthflow | Voiceflow |
|---|---|---|---|---|
| Latency | ~600ms | Good | <100ms | ~500ms |
| Free Tier | $10 credit | Trial | Free builder | Free |
| Per-Minute Cost | $0.07+ | ~$0.12 | ~$0.08 | Usage-based |
| Drag-and-Drop | Yes | Yes | Yes | Best |
| Concurrent Calls | 20 (free) | High | Scalable | Varies |
| Best For | Healthcare | Scale | Agencies | No-code |