Skip to main content
Best AI Tools FreeBest AI Tools Free
Retell AI - Free AI Tool

Retell AI

Conversational voice AI API for developers to build voice agents.

4.7(333 reviews)
Paid
Featured
Trending
What is Retell AI?
Retell AI is a platform for building production-ready AI voice agents for automated phone calls. Its proprietary voice orchestration engine enables conversations with a ~600ms response time, managed by a model that knows when to listen. The system offers a configurable agentic framework with drag-and-drop design, real-time function calling for booking appointments, and streaming RAG for knowledge base integration. It connects with tools like Twilio, Hubspot, and Make, providing call analytics and transcripts for review and offering full API access for custom development. The service is built for developers and operations managers in sectors such as healthcare, financial services, and logistics. Common applications include deploying AI receptionists for appointment setting, automating lead qualification calls, or running high-volume survey campaigns. Users deploy agents from pre-built templates or integrate them into existing CRMs and support stacks via API and webhooks. This allows human teams to offload repetitive call tasks and focus on complex customer interactions that require direct intervention.

Related AI Tools

Nanonets

Nanonets

AI-based OCR software to automate data capture from documents.

UiPath Document Understanding

UiPath Document Understanding

AI-powered document processing for RPA workflows.

Ajelix

Ajelix

Ajelix is an agentic AI chatbot for professionals that turns data into completed projects, generating formulas, scripts, dashboards, and presentations from plain English requests.

DocsBot AI

DocsBot AI

Create AI chatbots and content from your documentation.

Alby.email

Alby.email

Build and run AI agents you own on your Mac or server. Connect to WhatsApp, Instagram, email, and more. Free, no cloud, no account.

Bland AI

Bland AI

Platform to build, test, and scale AI phone calling bots.

Datacap

Datacap

IBM's cognitive capture software for document processing.

SuperChat.ai

SuperChat.ai

SuperChat.ai is an AI-driven assistant that manages tasks like booking flights, handling calls, and managing payments. It integrates various functions to streamline daily activities and save time.

Key Benefits & Features
✓
Proprietary Voice AI Orchestration delivering human-quality, low-latency phone conversations at scale
✓
Lowest latency with ~600ms response time
✓
Ultra realistic voice built from real performance data and human-guided training
✓
Proprietary turn-taking model that knows when to stop and listen
✓
Highly configurable agentic framework with drag-and-drop design, built-in guardrails, and full control over agent behavior
✓
Real-time function calling with preset functions for booking appointments, processing payments, updating records, and transferring calls
✓
Streaming RAG for knowledge base integration
✓
Pay-as-you-go pricing with no annual contracts, starting at $0 with $10 free credits
✓
Full platform access, pre-built agent templates, call analytics and transcripts, simulation testing, webhooks and API access, 20 free concurrent calls
✓
Enterprise plan with dedicated implementation support, custom MSA/DPA terms, role-based access control, dedicated stable server, custom SSO, high cap on concurrent calls, and 24/7 omnichannel support
Retell AI Pricing
Pricing modelPaid
Starting price$0.07 / Minute
Free planNo
Free trialNo
Billing—

Detailed Pricing Info

Retell AI is available under a Paid model. Check their official website for detailed subscription tiers and latest offers.
Pros & Cons of Retell AI
Pros
  • Engineered for low-latency responses, achieving under 800ms to enable more natural, human-like conversations.
  • Provides developers with SDKs and an API to integrate various LLMs and text-to-speech providers.
  • Agents can ingest knowledge from website URLs or sitemaps to answer questions from existing documentation.
Cons
  • Pricing is complex; the final per-minute cost depends on a combination of infrastructure, LLM, and telephony fees.
  • Requires significant developer effort to configure advanced workflows, making it less accessible for non-technical users.
Frequently Asked Questions

What is Retell AI?

Retell AI is a voice-first conversational AI platform that allows you to build, deploy, and manage AI voice agents for automating phone calls. It uses LLMs to create human-like conversations and supports complex, multi-turn interactions.

What are the primary use cases for Retell AI?

Retell AI is used for various applications such as receptionist services, appointment setting, lead qualification, customer service, debt collection, and surveys.

How does Retell AI handle unexpected inputs during calls?

Retell AI is designed to handle edge cases and unexpected inputs with its advanced LLM-based voice agents, ensuring smooth and natural conversations.

Can I test Retell AI before deploying it?

Yes, you can test Retell AI in text or real audio, manually or automatically, before an agent takes a real call. This helps in catching regressions and comparing agents or prompts.

Does Retell AI offer a pay-as-you-go pricing model?

Yes, Retell AI offers a pay-as-you-go pricing model where you only pay for the minutes you use, starting at $0.07 per minute.
Classification

Main Categories

AI Agents & Automation

Related Topics

#customer
#ai
#2026
User Reviews & Ratings
4.7(333 reviews)

Write a Review

Community Feedback (0)

Ready to try Retell AI?

CategoryAI Agents & Automation
Pricing ModelPaid
Global Rating4.7 / 5.0
Free Plan AvailableNo
Last Updated8/26/2026
Strong Similar Tools
Nanonets

Nanonets

AI-based OCR software to automate data capture from documents.

UiPath Document Understanding

UiPath Document Understanding

AI-powered document processing for RPA workflows.

Ajelix

Ajelix

Ajelix is an agentic AI chatbot for professionals that turns data into completed projects, generating formulas, scripts, dashboards, and presentations from plain English requests.

DocsBot AI

DocsBot AI

Create AI chatbots and content from your documentation.

Alby.email

Alby.email

Build and run AI agents you own on your Mac or server. Connect to WhatsApp, Instagram, email, and more. Free, no cloud, no account.

Related Tools
Bland AI

Bland AI

Platform to build, test, and scale AI phone calling bots.

Datacap

Datacap

IBM's cognitive capture software for document processing.

SuperChat.ai

SuperChat.ai

SuperChat.ai is an AI-driven assistant that manages tasks like booking flights, handling calls, and managing payments. It integrates various functions to streamline daily activities and save time.