AssemblyAI Voice Agent API vs Vapi
Pricing last verified from each vendor's own site.
Verdict
AssemblyAI bundles the whole agent stack into $4.50/hr (about $0.075/min), billed per second. Vapi is an orchestration platform that bills per minute with transcriber, model and voice costs listed separately, plus $5 free credits.
- Consider AssemblyAI Voice Agent API if: You want a single predictable per-minute price.
- Consider Vapi if: You want to mix providers and use Vapi's tooling.
Factual summary
- Both are listed under Voice AI & Dialers.
- Directly comparable starting prices are not available for both: AssemblyAI Voice Agent API — Voice Agent API $4.50/hr (about $0.075/min) all-in: real-time speech-to-text, turn detection, its Voice Agent LLM, text-to-speech and hosting, billed per second; speech-to-text from $0.15/hr; free tier (no card) includes up to 185 hours of pre-recorded and 333 hours of streaming transcription; volume pricing via sales; Vapi — Usage-based per minute, with transcriber, model and voice costs listed separately; $5 free credits; optional support packages: Core $29/mo, Pro $999/mo minimum.
This is a factual comparison drawn from vendor sites, not a recommendation. Which fits depends on your channels, volume and budget.
| AssemblyAI Voice Agent API | Vapi | |
|---|---|---|
| Summary | Speech-to-text API provider with an all-inclusive Voice Agent API for building AI phone agents. | Developer platform for building voice AI agents. |
| Starting price | See vendor | See vendor |
| Pricing details | Voice Agent API $4.50/hr (about $0.075/min) all-in: real-time speech-to-text, turn detection, its Voice Agent LLM, text-to-speech and hosting, billed per second; speech-to-text from $0.15/hr; free tier (no card) includes up to 185 hours of pre-recorded and 333 hours of streaming transcription; volume pricing via sales | Usage-based per minute, with transcriber, model and voice costs listed separately; $5 free credits; optional support packages: Core $29/mo, Pro $999/mo minimum |
| Model | usage | usage |
| Free trial | — | — |
| Free plan | Yes | — |
| Channels | phone | phone |
| Last verified | 2026-10-27 | 2026-10-28 |
FAQ
What is the difference between AssemblyAI Voice Agent API and Vapi?
AssemblyAI bundles the whole agent stack into $4.50/hr (about $0.075/min), billed per second. Vapi is an orchestration platform that bills per minute with transcriber, model and voice costs listed separately, plus $5 free credits.
Which is cheaper, AssemblyAI Voice Agent API or Vapi?
We can't compare entry prices directly. AssemblyAI Voice Agent API: Voice Agent API $4.50/hr (about $0.075/min) all-in: real-time speech-to-text, turn detection, its Voice Agent LLM, text-to-speech and hosting, billed per second; speech-to-text from $0.15/hr; free tier (no card) includes up to 185 hours of pre-recorded and 333 hours of streaming transcription; volume pricing via sales. Vapi: Usage-based per minute, with transcriber, model and voice costs listed separately; $5 free credits; optional support packages: Core $29/mo, Pro $999/mo minimum.
When should I choose AssemblyAI Voice Agent API over Vapi?
Consider AssemblyAI Voice Agent API if: You want a single predictable per-minute price. Consider Vapi if: You want to mix providers and use Vapi's tooling.
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