Compare Lab
Same questions. Your shortlist.
Compare 27 voice AI platforms and components across seven buying contexts, with sourced capabilities, current price captures and visible unknowns.
Test opening hours, booking conflicts and an unanswered transfer.
Retell AIVapi
Decision signals / differences first
Start where the records differ.
Values and evidence states are compared together. Shared facts follow the differences; Unknown never means No.
| Decision point | Retell AI | Vapi |
|---|---|---|
| Billing modelDifferent records | component-stack | platform-plus-pass-through |
| Billing unitShared state | minute | minute |
| Bring your telephonyShared state | Yes | Yes |
| Bring your modelShared state | Yes | Yes |
| Warm transferShared state | Yes | Yes |
| HIPAA pathShared state | Yes | Yes |
Your requirements & next steps
Carried from your shortlist
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Ready-made / AI receptionist · Strict evidence mode
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Unknown ≠ No
Pricing model
Retell AI
component-stack
Reviewed current public offer; retain original billing scope and units.
Vapi
platform-plus-pass-through
Reviewed current public offer; retain original billing scope and units.
Headline / base price
Retell AI
Voice-agent configuration range $0.07–$0.31/min
Reviewed current public offer; retain original billing scope and units.
Vapi
$0.05/min Vapi hosting
Reviewed current public offer; retain original billing scope and units.
Billing unit
Retell AI
minute
Reviewed current public offer; retain original billing scope and units.
Vapi
minute
Reviewed current public offer; retain original billing scope and units.
Platform fee
Retell AI
PAYG $0; optional recurring number/concurrency/KB charges
Zero platform fee is not zero total fixed cost.
Vapi
$0 Usage-only; optional Core $29/mo; Pro 10% hosting spend with $999/mo minimum
Reviewed current public offer; retain original billing scope and units.
Included usage
Retell AI
20 concurrent call slots and first 10 knowledge bases; call usage billed separately
Paid extras$8/slot/month and$8/KB/month; usage separate.
Vapi
Usage-only: 4 concurrent lines for new accounts; this is not included call minutes
Reviewed current public offer; retain original billing scope and units.
Overage
Retell AI
Metered usage; selected model, voice, carrier and add-ons determine rate
Reviewed current public offer; retain original billing scope and units.
Vapi
Usage is metered; extra call lines $10/month each
Reviewed current public offer; retain original billing scope and units.
Pass-through costs
Retell AI
Telephony, selected LLM/TTS, add-ons and concurrency burst can add charges
Reviewed current public offer; retain original billing scope and units.
Vapi
LLM, transcriber, voice and carrier charges; HIPAA add-on $2,000/month
Reviewed current public offer; retain original billing scope and units.
Free offer
Retell AI
$10 free credits
Reviewed current public offer; retain original billing scope and units.
Vapi
$5 free credits
Reviewed current public offer; retain original billing scope and units.
Complete cost ceiling
Retell AI
Unknown
A headline configuration range is not a ceiling on telephony, model, add-on or burst charges.
Vapi
Unknown
Provider choices, tokens, carrier and optional support/compliance fees are not fixed by minutes alone.
What remains unresolved
Retell AI
A headline configuration range is not a ceiling on telephony, model, add-on or burst charges.
Research conclusion about cost completeness, not a vendor capability.
Vapi
Provider choices, tokens, carrier and optional support/compliance fees are not fixed by minutes alone.
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 ↗351 pair views · one market
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Full platforms and components answer different questions. Every pair is browseable; only reviewed editorial pairs enter the index.
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