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Side-by-side facts to help you choose between voice agents or platforms.
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Voice Agent Platform
AssemblyAI
Voice AI infrastructure and managed Voice Agent API for production real-time voice agents.
Developer API
Deepgram
Developer voice AI platform with a unified Voice Agent API for building real-time conversational agents.
Highlighted rows differ between these picks
| Attribute | AssemblyAI | Deepgram | Synthflow |
|---|---|---|---|
| Platform type | Voice Agent Platform | Developer API | AI Receptionist |
| Pricing | $0.075/min $4.50/hour ($0.075/min) | $0.075/min $4.50/hour ($0.075/min) for Voice Agent API | Enterprise pricing Enterprise contracts from $30,000/year; no self-serve plan |
| Test it | Open live demo | Open live demo | (740) 284-8845 |
| Calls | Inbound, Outbound | Inbound, Outbound | Inbound, Outbound |
| Human handoff | No | Yes | Yes |
| Setup difficulty | Technical | Technical | Easy |
| Use cases | Customer Support Appointment Scheduling Lead Qualification Healthcare Intake | Customer Support Appointment Scheduling Lead Qualification Order Taking | AI Receptionists Appointment Scheduling Lead Qualification Customer Support |
| Useful for |
|
|
|
| Integrations | |||
| WebSocket API | — | ||
| Custom API | — | ||
| Twilio | — | ||
| Tool calling | — | — | |
| LLM Gateway | — | — | |
| Guardrails | — | — | |
| Function calling | — | — | |
| BYO LLM | — | — | |
| BYO TTS | — | — | |
| HubSpot | — | — | |
| +4 more across these tools — see each profile for the full list. | |||
Platform type
- AssemblyAI
- Voice Agent Platform
- Deepgram
- Developer API
- Synthflow
- AI Receptionist
Pricing
- AssemblyAI
$0.075/min
$4.50/hour ($0.075/min)
- Deepgram
$0.075/min
$4.50/hour ($0.075/min) for Voice Agent API
- Synthflow
Enterprise pricing
Enterprise contracts from $30,000/year; no self-serve plan
Test it
- AssemblyAI
- Open live demo
- Deepgram
- Open live demo
- Synthflow
- (740) 284-8845
Calls
- AssemblyAI
- Inbound, Outbound
- Deepgram
- Inbound, Outbound
- Synthflow
- Inbound, Outbound
Human handoff
- AssemblyAI
- No
- Deepgram
- Yes
- Synthflow
- Yes
Setup difficulty
- AssemblyAI
- Technical
- Deepgram
- Technical
- Synthflow
- Easy
Use cases
- AssemblyAI
- Customer SupportAppointment SchedulingLead QualificationHealthcare Intake
- Deepgram
- Customer SupportAppointment SchedulingLead QualificationOrder Taking
- Synthflow
- AI ReceptionistsAppointment SchedulingLead QualificationCustomer Support
Useful for
- AssemblyAI
- • Developer teams
- • Real-time voice agents
- • Streaming speech accuracy
- Deepgram
- • Developer teams
- • Real-time voice agents
- • Enterprise voice infrastructure
- • Teams wanting a unified voice stack
- Synthflow
- • No-code setup
- • AI receptionists
- • Appointment workflows
Integrations
| AssemblyAI | Deepgram | Synthflow | |
|---|---|---|---|
| WebSocket API | — | ||
| Custom API | — | ||
| Twilio | — | ||
| Tool calling | — | — | |
| LLM Gateway | — | — | |
| Guardrails | — | — | |
| Function calling | — | — | |
| BYO LLM | — | — | |
| BYO TTS | — | — | |
| HubSpot | — | — |
+4 more across these tools — see each profile for the full list.
What would these cost to run?
Enter your call volume once and see AssemblyAI, Deepgram and Synthflow priced at the same usage, ranked alongside every other platform.