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AssemblyAI vs Speechify
AssemblyAI is positioned as transcription APIs for live and recorded audio, with model-specific language and analysis options. Speechify is positioned as a developer TTS API under SpeechifyAI, distinct from the consumer reading su
AssemblyAI is positioned as transcription APIs for live and recorded audio, with model-specific language and analysis options. Speechify is positioned as a developer TTS API under SpeechifyAI, distinct from the consumer reading subscription. Start by deciding who owns the missing layers, then inspect the documented differences below.
STT and Voice Engines are different product categories. An underlying engine or framework is not a complete substitute for a deployed agent workflow.
8 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 | Speechify |
|---|---|---|
| Billing modelDifferent records | component-stack | character-credit |
| Billing unitDifferent records | Async audio hours; streaming connection hours; agent session minutes; gateway tokens | Monthly plan + character-based synthesis debited from USD usage balance |
| Bring your telephonyDifferent records | Yes | Unknown |
| Bring your modelDifferent records | Yes | Unknown |
| Warm transferDifferent records | Unknown | Not applicable |
| HIPAA pathDifferent records | Yes | 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.
Paid monthly subscription includes USD usage balance consumed by character-priced synthesis. Agent quote separate.
Model rates are scoped; add-ons stack; reference states updated May 29, 2026 and conflicts are retained.
Captured pricing summary does not provide complete per-character rate/balance table; full pricing evidence requested. Do not use consumer reader plans.
Idle streaming connection duration is billable. No fabricated all-in phone cost per minute.
Enterprise agent pricing excluded from this ladder.
SSO costs $199 per connection per month; do not mistake no base fee for no fixed optional charges.
Included USD usage balance and per-character usage, not all-in agent minutes.
Not a fixed monthly audio allowance; credits do not expire.
Captured pricing summary does not provide complete per-character rate/balance table; full pricing evidence requested. Do not use consumer reader plans.
No invented bundle overage.
In-flight requests continue and small overshoot is possible; not a guaranteed complete monthly ceiling.
Component choices and call mix must be specified.
Separate provider credentials and buyer deployment.
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.
Self-serve TTS balance does not determine telephony, recognition, LLM and hosting spend; enterprise agent quote unknown.
No complete phone bill ceiling from minutes alone; carrier, model and addon scope vary.
Self-serve TTS balance does not determine telephony, recognition, LLM and hosting spend; enterprise agent quote 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.
Speechify
Consumer and API plans are different products.
Free $0; Starter $10; Pro $99; Scale $499 per month · V3.3 evidence review · Starter TTS API plan; credit/character schedule unresolved; Enterprise Agents separate quote
Excluded / confirm: Complete cost cannot be established from this reference. Self-serve TTS balance does not determine telephony, recognition, LLM and hosting spend; enterprise agent quote unknown. · External STT, LLM, orchestrator, carrier and hosting
Paid monthly subscription includes USD usage balance consumed by character-priced synthesis. Agent quote separate.
The evidence overlap.
Both records have documented values for Product type, Technical setup, Pricing model, Published numeric pricing, Realtime / streaming audio, 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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