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AssemblyAI vs Speechmatics
AssemblyAI is positioned as transcription APIs for live and recorded audio, with model-specific language and analysis options. Speechmatics is positioned as recognition APIs with cloud and private-deployment choices for transcript
AssemblyAI is positioned as transcription APIs for live and recorded audio, with model-specific language and analysis options. Speechmatics is positioned as recognition APIs with cloud and private-deployment choices for transcription-heavy products. Start by deciding who owns the missing layers, then inspect the documented differences below.
10 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 | AssemblyAI | Speechmatics |
|---|---|---|
| Billing unitDifferent records | Async audio hours; streaming connection hours; agent session minutes; gateway tokens | Credits (1 credit = $1); product-specific per-hour rates, calculated to the second |
| Bring your telephonyDifferent records | Yes | Unknown |
| Bring your modelDifferent records | Yes | Not applicable |
| HIPAA pathDifferent records | Yes | Yes |
| Billing modelShared state | component-stack | component-stack |
| Warm transferShared state | Unknown | Unknown |
Your requirements & next steps
Your requirements
Ready-made / AI receptionist · Strict evidence mode
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STT hours/session duration, agent minutes, gateway tokens and add-ons remain distinct.
Credit billing: one credit equals $1; usage measured by product hours/seconds. This does not mean a character-priced TTS rate or flat agent minute rate.
Model rates are scoped; add-ons stack; reference states updated May 29, 2026 and conflicts are retained.
Price page exposes a Pro 0.129 figure without a clear unit in captured content; exact model rate and enterprise commitment require confirmation.
Idle streaming connection duration is billable. No fabricated all-in phone cost per minute.
Billing currency versus usage unit kept distinct.
SSO costs $199 per connection per month; do not mistake no base fee for no fixed optional charges.
No fixed subscription number inferred from credit billing.
Not a fixed monthly audio allowance; credits do not expire.
Existing pre-August accounts have different transition grant.
No invented bundle overage.
No forced per-minute bundle conversion.
Component choices and call mix must be specified.
Buyer-selected component costs sit outside speech API usage.
Not yet researched against this buyer-critical field standard.
Not yet researched against this buyer-critical field standard.
No complete phone bill ceiling from minutes alone; carrier, model and addon scope vary.
Speech component credits and contract-specific workloads do not determine full voice-agent cost; external LLM/hosting/telephony unknown.
No complete phone bill ceiling from minutes alone; carrier, model and addon scope vary.
Speech component credits and contract-specific workloads do not determine full voice-agent cost; external LLM/hosting/telephony unknown.
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.
AssemblyAI
A transcription hour is not a complete agent hour.
Universal-2 async / Universal-Streaming $0.15/hour; U3.5 Pro async $0.21/hour; U3 realtime $0.45/hour; Voice Agent $0.075/min · V3.3 evidence review · Voice Agent API reference; standalone STT is hourly; transport/add-ons separate
Excluded / confirm: Complete cost cannot be established from this reference. No complete phone bill ceiling from minutes alone; carrier, model and addon scope vary. · Twilio carrier; optional custom/Gateway LLM; standalone STT add-ons and per-channel billing
STT hours/session duration, agent minutes, gateway tokens and add-ons remain distinct.
Speechmatics
The lowest advertised batch price is not a real-time price.
Pro self-serve PAYG; Enterprise contract billing · V3.3 evidence review · STT exact-second metering billed in audio hours; no verified current complete rate schedule
Excluded / confirm: Complete cost cannot be established from this reference. Speech component credits and contract-specific workloads do not determine full voice-agent cost; external LLM/hosting/telephony unknown. · External LLM, orchestrator, telephony and application hosting
Credit billing: one credit equals $1; usage measured by product hours/seconds. This does not mean a character-priced TTS rate or flat agent minute rate.
The evidence overlap.
Both records have documented values for Product type, Technical setup, Pricing model, Published numeric pricing, Free trial, Realtime / streaming audio, Transcripts, Published included concurrency at least, 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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