Overview
Retell AI is an enterprise-grade platform for building, testing, deploying, and monitoring hyper-realistic AI voice agents at scale. The platform enables businesses to automate customer interactions through natural-sounding conversations that closely mimic human speech patterns and responsiveness.
Designed for both developers and business teams, Retell AI provides comprehensive infrastructure for creating conversational voice agents capable of handling inbound and outbound calls across multiple industries. The platform integrates with popular telephony providers like Twilio and Vonage, supports custom LLM integration via websocket, and offers real-time transcription with live monitoring capabilities.
Retell AI's architecture delivers end-to-end latencies as low as 600 milliseconds, measured from when the user stops speaking to when the AI agent begins responding. The platform supports over 50 languages and can handle high call volumes. Retell states an average 99.99% uptime with built-in fallback mechanisms. Enterprise compliance is addressed through SOC 2 Type I & Type II reports, HIPAA readiness for healthcare use cases, and GDPR compliance, though Retell does not currently operate services within the European Union.
Key Features
Hyper-Realistic Voice Quality — Delivers natural, human-like conversations through advanced speech synthesis and real-time processing, creating engaging customer experiences that closely approximate human agent interactions.
Ultra-Low Latency Performance — Achieves end-to-end response latencies as low as 600 milliseconds, measured from when the user stops speaking to when the AI agent begins responding. Actual latency varies by configuration and selected models.
Custom LLM Integration — Supports integration of your own large language models via websocket connection, enabling personalized conversational experiences with full control over AI behavior and responses.
Multilingual Support — Supports over 50 languages with voice availability varying by selected provider (ElevenLabs, Cartesia, MiniMax, OpenAI). Agents can be configured with a specific locale or multi mode for automatic language detection.
Enterprise-Grade Scalability — Designed to handle high-volume operations with millions of calls. Pay-as-you-go plans include 20 free concurrent calls, while enterprise plans offer additional included concurrency and custom limits based on volume.
Comprehensive Developer Tools — Offers official SDKs for Node.js and Python with type safety, built-in authentication, structured error handling, plus simulation testing, analytics dashboard, and latency tracking for debugging.
Advanced Security & Compliance — SOC 2 Type I & Type II compliant with HIPAA readiness for healthcare deployments and GDPR compliance. Includes PII redaction features that automatically detect and remove sensitive information from transcripts and recordings.
Real-Time Monitoring — Provides live transcription capabilities, call history with shareable log links for debugging, and analytics dashboard with LLM and websocket roundtrip latency tracking for informed optimization.
Pricing & Plans
Retell AI advertises no platform fees, with usage-based pricing that varies by selected components. New users receive $10 in free credits to explore the platform before committing to paid usage.
Pay-as-You-Go Plan:
- AI Voice Agents: Starting at $0.07+ per minute (varies by voice engine, LLM, and telephony choices)
- AI Chat Agents: Starting at $0.002+ per message for text-based interactions
- Included Features: Pre-built functions, simulation testing, analytics dashboard, 20 free concurrent calls, 10 free knowledge bases
- Free Credits: $10 credit included for platform exploration
- Support: Discord community and email support
Component Pricing:
Total cost is usage-based and typically combines:
- Voice Engines: Pricing varies by provider (ElevenLabs, Cartesia, MiniMax, OpenAI) and model selection
- Large Language Models: Token-based pricing depending on model choice and conversation length
- Telephony Services: Varies by provider, direction (inbound/outbound), and country
- Phone Numbers: Depends on telephony setup. Retell notes no charge for custom phone numbers in certain configurations, though carrier fees may apply
Enterprise Plan:
- Eligibility: Positioned for companies with large call volumes (Retell's pricing page mentions over $3,000 per month as a guideline)
- Pricing: Volume-based discounts customized to usage levels
- Included Benefits: Fully managed agent setup, additional included concurrency and custom concurrent call limits based on volume, early access to beta features, higher limits on knowledge bases
- Premium Support: Dedicated private Slack channel for priority assistance
Pricing Flexibility:
Retell's modular pricing structure allows businesses to optimize costs by selecting specific providers and models for their use case. Final costs depend on your configuration choices and usage volume. Enterprise customers should contact sales for volume discounts and custom deployment options.
Pros & Cons
Pros:
- Natural voice quality with hyper-realistic speech synthesis creates engaging customer interactions
- Ultra-low latency of 600ms enables fluid, natural-feeling conversations
- Comprehensive developer tooling with official Node.js and Python SDKs plus simulation testing
- Enterprise-grade security with SOC 2 Type I & II compliance, HIPAA readiness, and PII redaction features
- Flexible integration options with custom LLM support, Twilio, Vonage, and Zapier
- No platform fees model with transparent component-based pricing
- Multilingual support for 50+ languages with automatic language detection capabilities
Cons:
- Setup and configuration require technical expertise, which can be challenging for non-technical teams
- Deeper customization with custom LLMs and telephony integrations may require developer support
- Usage-based pricing can become expensive at high call volumes
- No current service operations within the European Union, despite GDPR compliance
Best For
- Customer service teams automating high-volume inbound support calls across multiple languages
- Sales organizations conducting outbound calling campaigns with personalized voice interactions
- Healthcare providers requiring HIPAA-ready voice automation for patient communications
- Enterprise development teams building custom voice agent solutions with specific LLM requirements
- Financial services firms needing SOC 2 compliant voice automation for customer interactions
- Businesses scaling from pilot programs to high-volume call operations
- Developer teams requiring comprehensive APIs, SDKs, and real-time debugging tools
FAQ
Is there a free trial available?
Yes, Retell AI provides $10 in free credits to new users upon signup, allowing exploration of the platform's voice agent capabilities and testing of features before committing to paid usage. The pay-as-you-go plan includes 20 free concurrent calls and 10 free knowledge bases.
What languages does Retell AI support?
Retell AI supports over 50 languages. Language availability and voice options vary by selected voice engine (ElevenLabs, Cartesia, MiniMax, OpenAI). Agents can be configured with a specific language/locale, or set to multi mode for multilingual support. Retell's documentation provides up-to-date language lists for each voice engine. The platform can detect and switch to a caller's preferred language in real-time depending on your configuration.
Can I integrate my own language models?
Yes, Retell AI supports custom LLM integration via websocket connection, allowing you to bring your own large language models for personalized conversational experiences. The platform provides official SDKs for Node.js and Python with type safety, built-in authentication, and structured error handling to simplify custom integration.
How does Retell AI handle data security and compliance?
Retell AI is SOC 2 Type I & Type II compliant and positions itself as HIPAA-ready for healthcare use cases. The platform is GDPR compliant through AWS infrastructure, though it does not currently operate services within the EU. All data transmitted during calls is encrypted both in transit and at rest. The platform offers PII redaction features that automatically detect and remove sensitive information such as names, addresses, dates of birth, passwords, and PINs from transcripts and recordings. Organizations with specific compliance requirements should review Retell's compliance documentation and follow the published compliance process for regulated deployments.
What latency can I expect for voice interactions?
Retell AI reports end-to-end latencies as low as 600 milliseconds, measured from when the user stops speaking to when the AI agent begins responding. Actual latency varies by configuration—certain features and model choices may increase response time. The platform provides latency monitoring tools to help track and optimize performance based on your specific setup.
How many concurrent calls can Retell AI handle?
The pay-as-you-go plan includes 20 free concurrent calls, suitable for small to medium deployments. Enterprise plans offer additional included concurrency and custom concurrent call limits based on volume requirements. Retell's infrastructure is designed to handle high-volume operations. Contact sales to discuss custom concurrency limits for large-scale deployments.
What telephony providers does Retell AI integrate with?
Retell AI provides seamless integration with popular telephony platforms including Twilio and Vonage for both inbound and outbound calling capabilities. The platform also integrates with Zapier for workflow automation and offers API-based connections for custom telephony implementations. Enterprise customers can request specific provider integrations.
How quickly can I deploy a voice agent?
Deployment time varies by use case complexity and technical requirements. Simple voice agents can be configured and tested within hours using pre-built functions and templates. More complex implementations requiring custom LLM integration, specific workflow logic, or enterprise compliance review typically require several days to weeks. The platform provides simulation testing tools to identify issues before production deployment, and enterprise customers receive fully managed agent setup support.
