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Comparison LabCompare 27 voice AI platforms and components across seven buying contexts, with sourced capabilities, current price captures and visible unknowns.Voice AI Price Index: prices, evidence and historyUnderstand the complete voice-agent cost stack: models, voice, transcription, telephony, subscriptions, capacity and add-ons.Know the cost before the first callEstimate monthly voice-agent costs, AI minutes, setup expenses and volume scenarios using your own transparent assumptions.AI voice agents for dentalAppointments, rescheduling and after-hours calls—with a person ready for clinical questions. Explore call flows, safe automation, integrations, tests and cost considerations.

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Fish Audio vs Hermes

Fish Audio is positioned as a developer speech API and creative voice workspace; paid TTS usage is metered in UTF-8 bytes. Hermes is positioned as an agency operations layer bundling voice providers, client workspaces and billing.

The decision in context

Fish Audio is positioned as a developer speech API and creative voice workspace; paid TTS usage is metered in UTF-8 bytes. 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.

6 jointly documented catalog fields. This measures evidence coverage, not equivalent quality or an overall winner.

Compare for the job

Test opening hours, booking conflicts and an unanswered transfer.

2 of 4 slots
Fish AudioHermes
Decision signals / differences first

Start where the records differ.

6 of 8 priority fields differ

Values and evidence states are compared together. Shared facts follow the differences; Unknown never means No.

Selected platforms: buyer-critical differences before detailed dimensions
Decision pointFish AudioHermes
Billing modelDifferent records
component-stackVerified Yes · 2026-09-28
monthly-bundleVerified Yes · 2026-09-28Documented product/configuration only; see research notes · Private beta; Starter
Billing unitDifferent records
TTS: million UTF-8 bytes; ASR: audio hours; Agents: conversation minutesVerified Yes · 2026-09-28
monthVerified Yes · 2026-09-28Documented product/configuration only; see research notes · Private beta; Starter
Bring your telephonyDifferent records
YesVerified Yes · 2026-09-28
UnknownUnknown after research · 2026-09-28Documented product/configuration only; see research notes
Bring your modelDifferent records
YesVerified Yes · 2026-09-28
UnknownUnknown after research · 2026-09-28Documented product/configuration only; see research notes
Warm transferDifferent records
YesConditional · 2026-09-28Phone transport and carrier-dependent transfer
UnknownUnknown after research · 2026-09-28Documented product/configuration only; see research notes
WebhooksDifferent records
YesVerified Yes · 2026-09-28API / webhook
YesVendor claim · 2026-09-28API / webhookDocumented product/configuration only; see research notes
Your requirements & next steps
Carried from your shortlist

Your requirements

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Ready-made / AI receptionist · Strict evidence mode

No personal requirements yet. Add criteria in Advanced Filter to prioritize this comparison.

Unknown ≠ No
Evidence, side by sideNo benchmark scores
Fish AudioVoice Engines
HermesFull Platforms
Pricing model
Fish Audio
component-stackVerified Yes · 2026-09-28

TTS uses UTF-8 bytes, ASR audio hours, Agents minutes plus carrier/model/add-ons. Multiple products must not share a fabricated normalized unit.

Hermes
monthly-bundleVerified Yes · 2026-09-28

Reviewed current public offer; retain original billing scope and units.

Documented product/configuration only; see research notes · Private beta; Starter
Headline / base price
Fish Audio
TTS $15/M UTF-8 bytes; ASR $0.36/audio hour; Agents $0.06/min + applicable surchargesVerified Yes · 2026-09-28

Free TTS model and Agents promotional basic LLM scope are separate.

Hermes
Starter $149/monthVerified Yes · 2026-09-28

Reviewed current public offer; retain original billing scope and units.

Documented product/configuration only; see research notes · Private beta; Starter
Billing unit
Fish Audio
TTS: million UTF-8 bytes; ASR: audio hours; Agents: conversation minutesVerified Yes · 2026-09-28

Each product keeps its own billing unit.

Hermes
monthVerified Yes · 2026-09-28

Reviewed current public offer; retain original billing scope and units.

Documented product/configuration only; see research notes · Private beta; Starter
Platform fee
Fish Audio
No API subscription fees or monthly minimumsVerified Yes · 2026-09-28

API access; managed numbers have separate rental and enterprise agreement may differ.

Hermes
Starter $149; Business $399; Agency $699/month; Enterprise customVerified Yes · 2026-09-28

Reviewed current public offer; retain original billing scope and units.

Documented product/configuration only; see research notes · Private beta; Starter
Included usage
Fish Audio
One-time $5 Agents trial balance; preview calls freeVerified Yes · 2026-09-28

Real sessions consume balance including relevant carrier/model charges; no monthly included minutes.

Hermes
Starter 300; Business 1,000; Agency 1,650 minutesVerified Yes · 2026-09-28

Reviewed current public offer; retain original billing scope and units.

Documented product/configuration only; see research notes · Private beta; Starter
Overage
Fish Audio
Metered charges debit prepaid API credit after trial balanceVerified Yes · 2026-09-28

Destination, transfer and selected model affect cost; no complete ceiling.

Hermes
UnknownConflicting evidence · 2026-09-28

Official overage rates conflict, messaging pass-through varies and beta account terms need confirmation.

Documented product/configuration only; see research notes · Private beta; Starter
Pass-through costs
Fish Audio
Phone destination surcharge, $1.20/month managed number, cold $0.015/min or warm $0.025/min post-transfer, non-basic LLM tokens; BYO carrier separateVerified Yes · 2026-09-28

Rates have explicit event/destination scope, not a single maximum.

Hermes
A2P messaging pass-through and customer billing configuration varyVerified Yes · 2026-09-28

Reviewed current public offer; retain original billing scope and units.

Documented product/configuration only; see research notes · Private beta; Starter
Free offer
Fish Audio
UnknownNot researched

Not yet researched against this buyer-critical field standard.

Hermes
UnknownUnknown after research · 2026-09-28

Official overage rates conflict, messaging pass-through varies and beta account terms need confirmation.

Private beta; Starter
Complete cost ceiling
Fish Audio
UnknownUnknown after research · 2026-09-28

Call mix, destination, transfer time, selected model/token usage and separate speech products prevent a universal complete monthly/minute ceiling.

Hermes
UnknownUnknown after research · 2026-09-28

Official overage rates conflict, messaging pass-through varies and beta account terms need confirmation.

Documented product/configuration only; see research notes · Private beta; Starter
What remains unresolved
Fish Audio
UnknownUnknown after research · 2026-09-28

Call mix, destination, transfer time, selected model/token usage and separate speech products prevent a universal complete monthly/minute ceiling.

Hermes
Official overage rates conflict, messaging pass-through varies and beta account terms need confirmation.Verified Yes · 2026-09-28

Research conclusion about cost completeness, not a vendor capability.

Documented product/configuration only; see research notes · Private beta; Starter

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.

Fish Audio

UTF-8 bytes and characters are not interchangeable for multilingual scripts.

TTS $15/M UTF-8 bytes; ASR $0.36/audio hour; Agents $0.06/min + applicable surcharges · V3.3 evidence review · TTS API reference; Voice Agents beta has separate minute-based billing

Excluded / confirm: Complete cost cannot be established from this reference. Call mix, destination, transfer time, selected model/token usage and separate speech products prevent a universal complete monthly/minute ceiling. · Phone destination surcharge, $1.20/month managed number, cold $0.015/min or warm $0.025/min post-transfer, non-basic LLM tokens; BYO carrier separate

component-stackVerified Yes · 2026-09-28

TTS uses UTF-8 bytes, ASR audio hours, Agents minutes plus carrier/model/add-ons. Multiple products must not share a fabricated normalized unit.

Read the complete profile →

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

monthly-bundleVerified Yes · 2026-09-28

Reviewed current public offer; retain original billing scope and units.

Documented product/configuration only; see research notes · Private beta; Starter
Read the complete profile →

The evidence overlap.

Both records have documented values for Product type, Pricing model, Published numeric pricing, Twilio, 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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Editorial index gate: noindex-cross-category. Different product layers. This pair is useful for architecture inspection, not a like-for-like purchase ranking.