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Retell AI

#1 AI Voice Agent Platform for Automating PHONE Calls

Visit Retell AI

Retell AI is a platform to build, test, deploy, and monitor AI voice and chat agents, with telephony, prompts, tools, and analytics built in. It targets phone-based use cases like appointment booking, lead qualification, call transfers, and IVR navigation, marketing ~600ms response latency.

Vendor's own claim
activation/deliveryorchestration/agent runtime

Core capabilities

Vendor's own claim
  • Two agent-building modes: node-based conversation flow and single-prompt agents
  • Voice and chat modalities, plus SMS and API access
  • Real-time function calling, appointment booking, lead qualification, call transfers
  • Call center features: warm transfer, IVR, DTMF
  • Knowledge base with website crawling and document upload, auto-synced
  • Batch calling
  • Post-call analysis with sentiment scoring and AI quality assurance
  • Live call monitoring, custom analytics, and A/B testing for agents
  • MCP server to manage agents from Cursor, Claude Desktop, and other MCP clients

API & agent surface

From official docs
Authentication
Bearer token: "Authorization: Bearer <RETELL_API_KEY>", same scheme for REST API and MCP server
Base URL
https://api.retellai.com
Rate limits
Documented only as a 429 "Account rate limited, please throttle your requests" response; specific request-per-minute thresholds are not published in the docs pages checked.
Notable endpoints
  • Create/list/get/delete phone or web calls
  • Create/update/publish/version agents
  • Import/provision/list phone numbers
  • Create knowledge bases, attach/remove sources
  • List voices, clone voices, search community voices
  • Create/assign/terminate chats
  • Create test cases, run QA, submit scores
  • Create/list alert rules and incidents, test webhooks
Machine-readable spec
OpenAPI spec retrieved

Pricing

From official docs
PlanPriceIncludedNotable
Pay-as-you-go$0.07-$0.31/min for voice agents (component-priced: voice infrastructure $0.055/min, TTS $0.015/min, LLM $0.003-$0.16/min, US telephony via Twilio $0.015/min, add-ons +$0.005-$0.01/min each); AI chat agents $0.001-$0.052/message$10 free credits, 20 concurrent calls
n/a
Full platform access, Pre-built agent templates, Call analytics and transcripts
EnterpriseCustom, volume-based50+ concurrent calls, no cap
n/a
24/7 omnichannel support with dedicated portal, Dedicated implementation support, Custom MSA/DPA terms

Checked 2026-08-03 against their pricing page. Vendors change pricing without notice.

What is Retell AI

Vendor's own claim

Retell AI is a voice/chat AI agent platform aimed at automating phone-based workflows for sectors like healthcare, financial services, insurance, logistics, retail, travel/hospitality, and debt collection.

Ideal customer profile

Vendor's own claim

Vendor markets to companies automating high-volume phone workflows - healthcare, financial services, insurance, logistics, retail, travel/hospitality, and debt collection - spanning both startups building on the pay-as-you-go plan and enterprises needing dedicated infrastructure, SSO, and custom terms.

Who should look elsewhere

Our read

Pricing is usage-based and stacks multiple metered components (voice infrastructure $0.055/min, TTS $0.015/min, LLM $0.003-$0.16/min, telephony $0.015/min, plus optional add-ons), so a team wanting a single flat per-minute number for budgeting has to model several line items rather than one price. Charges continue while the caller is silent because speech-to-text stays active, which penalizes use cases with long holds or pauses. Teams above 20 concurrent calls pay an extra $8/call/month for capacity on the pay-as-you-go tier, and anything beyond that (50+ concurrent, SSO, custom MSA/DPA) requires moving to custom Enterprise pricing rather than a published rate.

Retell AI alternatives

Our read

Platforms for building and running conversational voice agents that place or answer phone calls.

Category: Voice AI agents. Membership is decided by 2 stated tests, not by category tags — see them and the full comparison.

Retell AI FAQ

How is Retell AI priced?

Usage-based per minute, billed to the nearest second, built from separately metered components: voice infrastructure ($0.055/min), text-to-speech ($0.015/min for Retell voices), LLM ($0.003-$0.16/min depending on model), and telephony ($0.015/min for US via Twilio), plus optional add-ons. Chat agents are billed per message ($0.001-$0.052).

From official docs
Is there a free tier or trial?

New accounts get $10 in free credits with no commitment required; there is no separate time-boxed trial documented beyond that.

From official docs
Does the bill keep running if a caller goes silent?

Yes - per the pricing page, charges continue during silence because speech-to-text remains active; charges for the AI agent stop once a call is transferred to a human.

From official docs
What happens above 20 concurrent calls?

The pay-as-you-go plan includes 20 concurrent calls free; additional concurrency costs $8/call/month. Enterprise plans start at 50+ concurrent calls with no cap, at custom pricing.

From official docs

Verify before you buy

  • A GitHub org link confirmed from Retell's own site or docs (a plausible org exists but was not reached via a vendor-controlled link)
  • A specific official video URL/title from Retell's YouTube channel (channel link is in the vendor's own footer, but no specific video was verified)
  • Named MCP tool identifiers (docs describe functional areas, not individual tool names)
  • Numeric API rate-limit thresholds (only the 429 error behavior is documented)
  • Named MCP repo or agent-skill repo published by the vendor

Need help setting it up?

This page tells you whether Retell AI fits. Cheetah builds and runs the system it goes into — enrichment, sequencing, CRM and the joins between them.

Book a call →

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