Head to head · updated July 2026
Synthflow AI vs Retell AI: What You Need to Know
Synthflow's productized (but $2,000/mo) whitelabel vs Retell's wrapper-it-yourself economy — agencies pay the agency tax either way.
Synthflow AI
Synthflow AI is a no-code voice-agent builder for phone-based receptionist and appointment-booking use cases.
Best for: Non-technical teams launching phone agents from templates
Pricing: Usage-based from ~$0.08–$0.09/min + LLM & telephony add-ons; whitelabel listed at $2,000/mo or enterprise contracts from ~$30k/yr
STRONGEST WHEN
- +You want a mature template library for pure phone agents
- +Your clients' CRM/calendar stack is settled and staying
- +You can absorb the whitelabel add-on price at your scale
Retell AI
Retell AI is developer infrastructure for building voice and chat AI agents, priced per minute from unbundled components.
Best for: Developers building custom voice/chat agents on API rails
Pricing: $0.07–$0.31/min all-in, plus per-minute add-ons (KB, guardrails, PII, QA) and monthly fees per number
STRONGEST WHEN
- +You're a developer who values itemized infrastructure pricing
- +You're building your own product on voice rails, not delivering client front offices
- +You want granular control of every pipeline component
Synthflow AI vs Retell AI vs SeldonFrame
| Features | Synthflow AI | Retell AI | SeldonFrame |
|---|---|---|---|
| Best for | Non-technical teams launching phone agents from templates | Developers building custom voice/chat agents on API rails | Agencies & builders running AI front offices for clients |
| Pricing model | Usage-based from ~$0.08–$0.09/min + LLM & telephony add-ons; whitelabel listed at $2,000/mo or enterprise contracts from ~$30k/yr | $0.07–$0.31/min all-in, plus per-minute add-ons (KB, guardrails, PII, QA) and monthly fees per number | $29/mo flat — unlimited workspaces, no per-feature add-ons |
| AI receptionist (calls, SMS, chat) | Yes — no-code voice agents with booking flows | Voice + chat agents via API — you build the receptionist yourself | Native — AI receptionist answers, qualifies & books across voice, SMS & web chat |
| Website, CRM & booking behind the agent | None — voice agent only; CRM, website and calendar live elsewhere | None — no CRM, website or booking calendar | Included — multi-page website, CRM, booking calendar, intake forms, review requests in every workspace |
| Whitelabel & client workspaces | Yes, but as a $2,000/mo add-on or enterprise bundle | None native — third-party wrapper products fill the gap | Included — whitelabel client portal, per-client workspaces, custom domains, one-click multi-client deploy |
| AI usage costs | Per-minute, with engine/LLM/telephony components stacking | Metered per minute per component | BYOK — bring your own AI (and Twilio) keys and pay providers at raw cost, zero markup |
| Sell / resell what you build | Yes — via the (paid) whitelabel program | Certified-partner referrals, but no native whitelabel product | Built in — publish agents to the marketplace or rent them via MCP (5% marketplace fee) |
Need what both Synthflow AI and Retell AI do?
Most people running this comparison actually need the outcome underneath both tools: calls and chats answered, leads qualified, jobs booked into a real calendar and CRM, on a site the client owns. SeldonFrame ships that whole front office from one conversation — $29/mo flat, unlimited workspaces, your own AI keys at raw cost, whitelabel included.