Head to head
Vapi vs Synthflow
Written By Research Team
AI Outbound Calling
Fact Checked
All pricing verified against vendor documentation
Updated
Higher score
Vapi
The cheapest published platform rate and the most developer-flexible — if you can live with the compliance gap.
At $0.05/min Vapi has the lowest published platform rate here, and bringing your own model keys can take model cost to zero. For engineering teams it is the most composable option. But read the compliance row carefully: the self-serve Build tier has no SOC 2, no SSO and no RBAC, HIPAA is a $2,000/mo add-on, zero data retention is another $1,000/mo, and call history is kept only 14 days. Those controls arrive on the annual Scale contract.
Synthflow
Enterprise-only voice AI with ISO 27001 and EU hosting — and a $30,000 annual floor.
Synthflow has moved upmarket and now sells enterprise contracts only, starting at $30,000 per year. To its credit it publishes that floor, which most sales-gated vendors will not do. The compliance stack is the strongest here alongside Bland — SOC 2, HIPAA, GDPR and ISO 27001, with EU or US hosting. But there is no self-serve path at all: you cannot place a test call without going through sales.
Side by side
| Criterion | Vapi | Synthflow |
|---|---|---|
| Overall score | 76/100 | 69/100 |
| Rank | #5 | #8 |
| Type | Autonomous AI agent | Autonomous AI agent |
| Pricing model | Published | Sales-gated |
| Headline cost | $0.05/min on Build, plus model costs at cost (or $0 with your own keys) | Enterprise contracts start at $30,000 annually |
| Concurrency | 10 included, +$10/line/mo; custom on Scale | Custom concurrency planning with routing and escalation paths |
| Free trial | No stated trial credits; signup via dashboard | None |
| Certifications | SOC 2 (Scale tier only), HIPAA ($2,000/mo add-on), PCI (Scale), SSO & RBAC (Scale only) | SOC 2, HIPAA, GDPR, ISO 27001, EU and US hosting options, MSA/DPA support |
Score by criterion
| Criterion | Max | Vapi | Synthflow |
|---|---|---|---|
| Pricing transparency | 20 | 15 | 8 |
| Outbound capability | 20 | 16 | 15 |
| Compliance & security | 20 | 12 | 19 |
| Integrations & extensibility | 15 | 14 | 14 |
| Time to first call | 15 | 11 | 4 |
| Scale & reliability | 10 | 8 | 9 |