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Side-by-side facts to help you choose between voice agents or platforms.
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Voice Agent Platform
Retell AI
Voice AI platform for building low-latency phone agents across support, scheduling, and sales workflows.
AI Receptionist
Synthflow
No-code AI voice agent platform for business call automation, now sold through enterprise contracts.
Highlighted rows differ between these picks
| Attribute | Retell AI | Synthflow | Vapi |
|---|---|---|---|
| Platform type | Voice Agent Platform | AI Receptionist | Developer API |
| Pricing | $0.07-$0.31/min $0.07-$0.31/min; custom pricing available | Enterprise pricing Enterprise contracts from $30,000/year; no self-serve plan | $0.13-$0.33/min $0.05/min hosting + provider costs |
| Test it | Free trial | (740) 284-8845 | Free trial |
| Calls | Inbound, Outbound | Inbound, Outbound | Inbound, Outbound |
| Human handoff | Yes | Yes | Yes |
| Setup difficulty | Medium | Easy | Technical |
| Use cases | Customer Support Appointment Scheduling Lead Qualification AI Receptionists | AI Receptionists Appointment Scheduling Lead Qualification Customer Support | Customer Support Appointment Scheduling Lead Qualification Outbound Calling |
| Useful for |
|
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| Integrations | |||
| Zapier | |||
| Twilio | — | ||
| Custom API | — | ||
| CRM | — | ||
| Calendar | — | ||
| HubSpot | — | — | |
| Calendly | — | — | |
| Google Calendar | — | — | |
| Webhooks | — | — | |
Platform type
- Retell AI
- Voice Agent Platform
- Synthflow
- AI Receptionist
- Vapi
- Developer API
Pricing
- Retell AI
$0.07-$0.31/min
$0.07-$0.31/min; custom pricing available
- Synthflow
Enterprise pricing
Enterprise contracts from $30,000/year; no self-serve plan
- Vapi
$0.13-$0.33/min
$0.05/min hosting + provider costs
Test it
- Retell AI
- Free trial
- Synthflow
- (740) 284-8845
- Vapi
- Free trial
Calls
- Retell AI
- Inbound, Outbound
- Synthflow
- Inbound, Outbound
- Vapi
- Inbound, Outbound
Human handoff
- Retell AI
- Yes
- Synthflow
- Yes
- Vapi
- Yes
Setup difficulty
- Retell AI
- Medium
- Synthflow
- Easy
- Vapi
- Technical
Use cases
- Retell AI
- Customer SupportAppointment SchedulingLead QualificationAI Receptionists
- Synthflow
- AI ReceptionistsAppointment SchedulingLead QualificationCustomer Support
- Vapi
- Customer SupportAppointment SchedulingLead QualificationOutbound Calling
Useful for
- Retell AI
- • Fast voice prototypes
- • Support call automation
- • Scheduling workflows
- Synthflow
- • No-code setup
- • AI receptionists
- • Appointment workflows
- Vapi
- • Developer teams
- • Custom call workflows
- • Voice AI prototypes
Integrations
| Retell AI | Synthflow | Vapi | |
|---|---|---|---|
| Zapier | |||
| Twilio | — | ||
| Custom API | — | ||
| CRM | — | ||
| Calendar | — | ||
| HubSpot | — | — | |
| Calendly | — | — | |
| Google Calendar | — | — | |
| Webhooks | — | — |
What would these cost to run?
Enter your call volume once and see Retell AI, Synthflow and Vapi priced at the same usage, ranked alongside every other platform.