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Cartesia vs Retell AI
Cartesia is positioned as speech models for teams assembling a voice stack, with a separate managed-agent product. Retell AI is positioned as a configurable call-agent platform with visual flows, APIs and integrated call operation
Cartesia is positioned as speech models for teams assembling a voice stack, with a separate managed-agent product. Retell AI is positioned as a configurable call-agent platform with visual flows, APIs and integrated call operations. Start by deciding who owns the missing layers, then inspect the documented differences below.
Voice Engines and Full Platforms are different product categories. An underlying engine or framework is not a complete substitute for a deployed agent workflow.
13 jointly documented catalog fields. This measures evidence coverage, not equivalent quality or an overall winner.
Test opening hours, booking conflicts and an unanswered transfer.
Start where the records differ.
Values and evidence states are compared together. Shared facts follow the differences; Unknown never means No.
| Decision point | Cartesia | Retell AI |
|---|---|---|
| Billing unitDifferent records | TTS/STT credits; Managed Agents conversation minutes | minute |
| Bring your telephonyDifferent records | Yes | Yes |
| Bring your modelDifferent records | Yes | Yes |
| Warm transferDifferent records | Unknown | Yes |
| Billing modelShared state | component-stack | component-stack |
| HIPAA pathShared state | Yes | Yes |
Your requirements & next steps
Your requirements
Ready-made / AI receptionist · Strict evidence mode
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TTS/STT credit subscriptions and Managed Agents minute charges remain separate.
Reviewed current public offer; retain original billing scope and units.
Speech model credits and selected LLM/evaluation charges have separate scope.
Reviewed current public offer; retain original billing scope and units.
Product-specific units preserved.
Reviewed current public offer; retain original billing scope and units.
Plan allowances include separate agent prepayment; do not double-count as universal included voice minutes.
Zero platform fee is not zero total fixed cost.
Separate credit and agent budgets; no arbitrary cross-product minute conversion.
Paid extras$8/slot/month and$8/KB/month; usage separate.
Free allowances and product rates are available; old changelog, bandwidth trial and speech volume controls do not establish these current billing terms.
Reviewed current public offer; retain original billing scope and units.
LLM promotion ends October 1, 2026; quoted model/usage mix determines bill.
Reviewed current public offer; retain original billing scope and units.
Not yet researched against this buyer-critical field standard.
Reviewed current public offer; retain original billing scope and units.
Product mix, LLM promotion expiry, carrier routing and other metered components prevent a universal all-in ceiling.
A headline configuration range is not a ceiling on telephony, model, add-on or burst charges.
Product mix, LLM promotion expiry, carrier routing and other metered components prevent a universal all-in ceiling.
Research conclusion about cost completeness, not a vendor capability.
Anyone with this link can view the encoded decision criteria.
Vendor documentation establishes a claim. Public model benchmarks are separate context, not measurements of these platforms.
Open saved comparison ↗What to verify together.
Cartesia
A speech credit plan is not a complete phone-call bill.
Managed Agents $0.06/min; Cartesia-provided-number telephony $0.014/min · V3.3 evidence review · Managed Agents base rate; carrier/model charges and prepaid plan balances separate
Excluded / confirm: Complete cost cannot be established from this reference. Product mix, LLM promotion expiry, carrier routing and other metered components prevent a universal all-in ceiling. · LLM tokens after promotional coverage; telephony and evaluation usage
TTS/STT credit subscriptions and Managed Agents minute charges remain separate.
Retell AI
The advertised price band is not a ceiling for every model configuration.
Voice-agent configuration range $0.07–$0.31/min · V3.3 evidence review · Published configured-agent range lower reference; not a guaranteed all-in floor or ceiling
Excluded / confirm: Complete cost cannot be established from this reference. A headline configuration range is not a ceiling on telephony, model, add-on or burst charges. · Telephony, selected LLM/TTS, add-ons and concurrency burst can add charges
Reviewed current public offer; retain original billing scope and units.
The evidence overlap.
Both records have documented values for Product type, Technical setup, Pricing model, Published numeric pricing, Cartesia TTS, Function / tool calling, Silence handling, Webhooks, Published included concurrency at least, Local number availability, Official product documentation, Checked within 30 days and additional fields shown in Compare. Matching availability does not measure behavior under your call conditions.
Run the same booking, tool failure and unsuccessful human-transfer cases. Record both outcomes and billable units before signing a deployment agreement.
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