Compare Lab
Cartesia vs Hermes
Cartesia is positioned as speech models for teams assembling a voice stack, with a separate managed-agent product. Hermes is positioned as an agency operations layer bundling voice providers, client workspaces and billing. Start b
Cartesia is positioned as speech models for teams assembling a voice stack, with a separate managed-agent product. Hermes is positioned as an agency operations layer bundling voice providers, client workspaces and billing. 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.
5 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 | Hermes |
|---|---|---|
| Billing modelDifferent records | component-stack | monthly-bundle |
| Billing unitDifferent records | TTS/STT credits; Managed Agents conversation minutes | month |
| Bring your telephonyDifferent records | Yes | Unknown |
| Bring your modelDifferent records | Yes | Unknown |
| HIPAA pathDifferent records | Yes | Unknown |
| WebhooksDifferent records | YesAPI / webhook | YesAPI / webhook |
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.
Reviewed current public offer; retain original billing scope and units.
Separate credit and agent budgets; no arbitrary cross-product minute conversion.
Reviewed current public offer; retain original billing scope and units.
Free allowances and product rates are available; old changelog, bandwidth trial and speech volume controls do not establish these current billing terms.
Official overage rates conflict, messaging pass-through varies and beta account terms need confirmation.
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.
Official overage rates conflict, messaging pass-through varies and beta account terms need confirmation.
Product mix, LLM promotion expiry, carrier routing and other metered components prevent a universal all-in ceiling.
Official overage rates conflict, messaging pass-through varies and beta account terms need confirmation.
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.
Hermes
The service is advertised as a private beta with public launch pending.
Starter $149/month · V3.3 evidence review · Starter private beta subscription; unresolved overage scope
Excluded / confirm: Complete cost cannot be established from this reference. Official overage rates conflict, messaging pass-through varies and beta account terms need confirmation. · A2P messaging pass-through and customer billing configuration vary
Reviewed current public offer; retain original billing scope and units.
The evidence overlap.
Both records have documented values for Product type, Pricing model, Published numeric pricing, Checked within 30 days, Retained price snapshot. 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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