Retell AI
#1 AI Voice Agent Platform for Automating PHONE Calls
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.
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| Plan | Price | Included | Notable |
|---|---|---|---|
| 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 |
| Enterprise | Custom, volume-based | 50+ 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 claimRetell 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 claimVendor 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 readPricing 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 readPlatforms 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.
Appears in comparison shortlists
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).
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.
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.
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.
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.
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