AI voice agents
AI receptionists and voice agents: Retell, Vapi and the rest, costed per call minute.
3 tools comparedPrices verified on September 23, 2026
| Tool | Stacknota score | From | Free plan | Data in the EU | Best for | Link |
|---|---|---|---|---|---|---|
 VapiOur pick | 3.7 | $29per month, on top of usage | ✓ Yes | ✓ Yes | Developers and product teams that want to build their own voice agents via API and pick each component (model, voice, transcription). | Try |
 Retell AI | 3.6 | $0.07/min | ✓ Yes | ✗ No | Teams that want to launch AI phone agents on a per-minute basis, without an annual contract, and without an EU hosting requirement. | Try |
 Synthflow | 2.9 | $30,000/yr | ✗ No | Not published | Large companies and contact centers that want to deploy voice agents with full support and a substantial annual budget. | Try |
- From
- $29 per month, on top of usage
- Free plan
- ✓ Yes
- Data in the EU
- ✓ Yes
- Retell AI3.6
- From
- $0.07/min
- Free plan
- ✓ Yes
- Data in the EU
- ✗ No
- Synthflow2.9
- From
- $30,000/yr
- Free plan
- ✗ No
- Data in the EU
- Not published
Stacknota score: Price 25 %, Free plan and trial 15 %, Ease of use 20 %, Features 25 %, Data and GDPR 15 %. Our scoring grid
Guides
ReviewSynthflow review: enterprise contracts from $30,000 a year in 2026Synthflow now sells enterprise contracts only, from $30,000 a year. What that covers, who it fits, and what a small business can use instead.GuideVapi pricing: what a minute of calls costs and what the plans addVapi charges $0.05 a minute for hosting, plus provider costs passed through. Core runs $29 a month, Pro starts at $999, and sign up gives $5 in credits.ReviewRetell AI review: strengths, limits, and who it fitsOur documented Retell AI review: $0.07 to $0.31 per call minute, US-only hosting, the technical calls you have to make, and the limits to know first.GuideAI customer service by phone: what an AI voice agent can actually handleWhat an AI voice agent handles alone, when it must transfer, the per minute price at Retell AI and Vapi, and where your call data lives.GuideRetell AI pricing in 2026: what a minute of calls really costsRetell AI pricing is per minute: $0.07 to $0.31 depending on model and voice, $10 in free credits, phone numbers at $2 a month, and data held in the US.GuideAI Receptionist: How It Works and What It Costs Per MinuteWhat an AI receptionist really does on a call, the building blocks behind the price of a minute, and the data questions to ask before you sign anything.ComparisonAI receptionist platforms compared: Retell AI, Vapi and Synthflow in 2026Retell AI, Vapi and Synthflow let you build an AI receptionist or voice agent. Verified per-minute prices, data hosting and who each one suits.