Synthflow vs Vapi
Synthflow charges usage-based and Vapi charges usage-based. Here's how they compare on price, features and compliance, using each vendor's own published information.
Checked October 15, 2026 (Synthflow) and October 15, 2026 (Vapi)
| Detail | Synthflow | Vapi |
|---|---|---|
| Charges by | Usage-based | Usage-based |
| Starts at | $2,500/mo | Free tier |
| Includes | — | $5 in free credits; 1 phone number; 4 concurrent calls; 14-day data retention |
| Overage | — | — |
| Per minute | — | $0.05 |
| Free trial | — | $5 in free credits |
| How it works | AI only | AI only |
| Answers inbound calls | Yes | Yes |
| Places outbound calls | Yes | Yes |
| Books appointments | Yes | Yes |
| Warm transfer to a person | Yes | Yes |
| Text follow-up | Yes | Yes |
| Call recording | Yes | Yes |
| Transcripts | Yes | Yes |
| CRM sync | Yes | Yes |
| Keep your number (porting) | Unconfirmed | Unconfirmed |
| Spanish | Yes | Yes |
| Other languages | Yes | Yes |
| Web chat | Yes | Unconfirmed |
| API | Yes | Yes |
| Custom voice | Yes | Yes |
| Signs a HIPAA BAA | Yes | Yes |
| SOC 2 | SOC 2 Type II | SOC 2 Type II |
Integrations
Both list: Google Calendar, Five9, Genesys, Cisco, Avaya, GoHighLevel, Salesforce, HubSpot, Clay, Apollo.io, Twilio, Telnyx, Vonage, Zapier, Make, n8n, Zendesk.
Only Synthflow: Cal.com, Outlook Calendar, 8x8, RingCentral, OpenPhone, Dialpad, 3CX, JustCall, CloudTalk, Intermedia, Zoho CRM, Freshworks, ActiveCampaign, Monday.com, Pipedrive, Jobber, Follow Up Boss, Housecall Pro, Dentrix, Velocify, Practice Better, ServiceTitan, Bitrix24, athenaOne, Gong, Outreach, Asterisk, GoTo, Plivo, Ooma, Activepieces, Intercom, Stripe, Shopify, Airtable, WhatsApp.
Only Vapi: NICE, Talkdesk, Amazon Connect, Google Sheets, Notion, Slack.
Pricing notes
Synthflow: Synthflow's pricing page lists only an Enterprise offering: 'Enterprise contracts start at $30,000 annually' (shown here as $2,500/month, our conversion of the annual minimum). No per-minute rate is published. Telephony (Synthflow native telephony, SIP trunking or approved enterprise telephony), concurrency planning, integrations and launch support are scoped into the contract. The homepage FAQ separately says agents can be built for free and that launched agents move to pay-as-you-go billing for calls and chats. Synthflow's usage docs say calls are billed per second (rounded up), no-answer and voicemail hang-ups count as 5 seconds, failed calls are not billed, usage after a transfer is not counted, and 5 chat messages count as 1 usage minute. Rates come from each customer's agreement.
Vapi: Vapi charges a pre-paid hosting fee of $0.05/min. Transcription, LLM and voice are passed through at provider cost with no markup (calculator ranges: Deepgram transcription about $0.0095-$0.0099/min, OpenAI model about $0.0077-$0.0452/min, ElevenLabs voice about $0.0146-$0.0238/min). Vapi telephony/SIP, WebSockets and Daily WebRTC are free; carrier minutes are charged by the provider (Twilio $0.008/min inbound and $0.014/min outbound, Vonage $0.00814/min, Telnyx $0.0055/min). Vapi's own example for 1,000 minutes/month totals an estimated $82-$129. Add-ons on any package: HIPAA compliance $2,000/month (includes standard DPA and BAA), extra concurrency $10 per line per month, extra organizations $20 per org per month. The Pro package fee is 10% of the hosting fee with a $999/month minimum; it is recorded here at the minimum.