
Build, deploy, and manage human-like AI voice agents for automated phone call and chat automation.
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Retell AI offers a generous free tier with optional paid upgrades for advanced features.
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Retell AI utilizes a proprietary turn-taking model that intelligently determines when to speak and when to listen, mimicking human conversational flow. This prevents the awkward pauses or interruptions often found in older IVR or IVA systems, contributing to a smoother, more natural interaction.
Yes, Retell AI supports real-time function calling. You can add built-in or custom functions directly into call flows, enabling agents to execute tasks such as booking appointments, processing payments, updating customer records, or transferring calls, all within the conversation.
Streaming RAG (Retrieval Augmented Generation) allows Retell AI agents to access and utilize a knowledge base in real-time during conversations. This knowledge base automatically syncs with your latest website content, ensuring that the AI agent provides accurate and current answers to customer inquiries.
Retell AI supports both warm and cold call transfers. A cold transfer instantly redirects a call to a live agent without added context, ideal for quick redirects. A warm transfer includes a contextual briefing for the receiving agent, building trust and reducing repetition for the customer, perfect for high-touch service or escalations.
Retell AI offers SIP Trunking, allowing businesses to connect their existing phone numbers or VOIP providers. This ensures compatibility with current telephony setups and enables seamless integration without requiring a complete overhaul of communication infrastructure.
The pricing calculator allows users to select various LLMs (e.g., GPT-5, Claude 3.7 sonnet, Gemini 2.0 Flash) and different tiers (e.g., Fast Tier) which directly influence the 'LLM Cost' component of the total per-minute charge. This enables users to estimate costs based on their preferred AI model and performance requirements.
Source: retellai.com