Synthflow vs Vapi (2026): which should you pick?

Pick Synthflow if

• Fits if you want white-label voice agents under one annual contract
• Makes sense if you use Five9, Salesforce or HubSpot

Look elsewhere if

• Not for you if you want to try it, as the page says no free plan and no trial
• Skip it if you are a small business, since every deployment starts on an Enterprise contract
• Not for you if you want per-minute pricing, because the page says there is none
• Watch out: HIPAA is self-attested in the vendor's own Trust Center summary

Pick Vapi if

• Fits if you are a developer who wants to choose each voice and model provider
• Makes sense if you want to pay for minutes as you use them

Look elsewhere if

• Pricey if you want one price, as model, voice and call charges sit on top of the $0.05 hosting
• Watch out: HIPAA-eligible handling is a $2,000 a month add-on
• Pricey if you grow, since Pro has a $999 a month minimum
• Watch out: extra lines cost $10 each and extra organisations $20 each a month

Synthflow

• No prices are published. The pricing page says it is an annual enterprise agreement with no free plan, no trial and no per-minute rate.
• Every new deployment starts on an Enterprise contract, so it is not set up for self-serve small-business use.
• HIPAA is listed as self-attested in the vendor's own Trust Center summary.

Vapi

• Without a success package, hosting is $0.05 per minute, pre-paid, and Deepgram, model and voice costs are added on top; the page's 1,000-minute estimate is $82 to $129 a month.
• HIPAA-eligible data handling is a $2,000 per month add-on.
• Extra concurrent lines cost $10 per line per month and extra organizations $20 per organization per month.
• Twilio, Vonage and Telnyx call charges are billed by those providers, such as $0.008 per minute for Twilio inbound.

Synthflow

Voice agents for calls

Agents handle customer service, reception, answering service, concierge, appointment booking and IVR use cases over the phone.

Telephony options

The contract can use Synthflow Native Telephony, SIP trunking or approved enterprise telephony, with routing, escalation and fallback logic.

White label

BPOs and software platforms can run it under their own brand, with a workspace per client and one analytics dashboard across them.

Launch support

Where the agreement includes it, Synthflow's forward-deployed engineers implement, test and launch agents with your team. Deployments go live in weeks.

Security and compliance

The Trust Center lists SOC 2 Type 2, ISO 27001, GDPR, HIPAA (self-attested) and PCI DSS v4.0.1, with ISO 42001, DORA and the EU AI Act in progress.

Vapi

Voice agent orchestration

Configure voice, conversation flow, telephony and integrations for an agent, then deploy it behind a phone number or an API.

Choice of providers

The pricing calculator lets you pick the transcriber, language model and voice, for example Deepgram, OpenAI and ElevenLabs. Models are passed through at cost.

Testing and simulation

Calls can be simulated before they reach customers, and monitoring flags issues in live calls.

Telephony options

Vapi telephony and SIP, WebSockets and Daily WebRTC are listed as free transport; Twilio, Vonage and Telnyx are charged by those providers.

Enterprise controls

The site lists SSO, OAuth, RBAC and AI guardrails, and says SOC 2, HIPAA and PCI compliance are supported.

Synthflow

Pricing could not be confirmed. See synthflow.ai.

Vapi

• Core$29

  per month, pre-paid, auto-renew

  2 organizations, 5 included phone numbers, 10 concurrent calls, 30 days of raw data retention and email support.

• Pro$999

  per month minimum, 10% of the hosting fee

  10 organizations, 30 concurrent calls, 180 days retention, RBAC, a dedicated Slack channel and a 99% uptime SLA.

• PremierCustom

  Direct sales only: higher limits, named support team, 99.9% uptime SLA, SSO and dedicated SIP.