Retell AI vs Synthflow
A side-by-side comparison of capabilities, autonomy, integrations, and pricing to help you choose.
Short answer: choose Retell AI if you want platform to build, test, deploy, and monitor ai voice agents for calls (Autonomous agent, usage); choose Synthflow if you want no-code platform to build and run ai voice agents for phone calls (Autonomous agent, usage).
| Retell AI | Synthflow | |
|---|---|---|
| What it is | Platform to build, test, deploy, and monitor AI voice agents for calls | No-code platform to build and run AI voice agents for phone calls |
| Type | platform | platform |
| Autonomy | Autonomous agent | Autonomous agent |
| Pricing | usage · $0.07/min voice engine (model + telephony billed on top); Enterprise from $8,000 | usage · ~$0.09/min voice engine (LLM + telephony billed on top); free PAYG tier |
| Best for | developers, smb, mid-market, enterprise | smb, mid-market, enterprise, developers |
| Deployment | saas, api | saas, api |
| Modalities | voice, text, api | voice, text, api |
| Models | model-agnostic, gpt, claude | model-agnostic, gpt, proprietary |
| Protocols | rest-api, function-calling | rest-api, function-calling |
| Integrations | Twilio, Telnyx, Vonage, ElevenLabs, PlayHT | Twilio, Telnyx, RingCentral, Vonage, Salesforce, HubSpot |
| Capabilities | 4 documented | 4 documented |
Retell AI
- +Provider-flexible: bring your own telephony, voices, and LLM, or use Retell's built-in carrier
- +Structured Conversation Flow Agents (nodes and transitions) give fine control alongside looser prompt-based agents
- +Usage-based pricing with no mandatory base subscription and free credits to start; built-in testing and monitoring
- -Advertised $0.07/min covers only the voice engine; LLM, telephony, and international add to real per-minute cost
- -Building reliable structured flows for complex calls takes meaningful human setup
Synthflow
- +Genuinely no-code visual builder with fast setup, a common point of praise in reviews
- +In-house telephony plus broad SIP and CRM integration, with a white-label and reseller program for agencies
- +Natural low-latency voices (ElevenLabs) and a free pay-as-you-go tier to start
- -Per-minute cost adds up at volume once LLM and telephony are stacked on the voice-engine rate
- -LLM choice is OpenAI-centric in practice rather than fully model-agnostic
Which should you choose?
Retell AI is platform to build, test, deploy, and monitor ai voice agents for calls, best for developers, smb, mid-market, enterprise. Synthflow is no-code platform to build and run ai voice agents for phone calls, best for smb, mid-market, enterprise, developers. The right choice depends on the autonomy level you want, your existing integrations, and your budget, all compared above.
This comparison is generated from the sourced Retell AI and Synthflow profiles. Open either profile to review its evidence and last-reviewed date.