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Retell AI vs Synthflow

A side-by-side comparison of Retell AI and Synthflow, two Voice tools, drawn from Ignaite's continuously-verified listings.

Compared from listings verified as of

Retell AI

Voice

Build, test, and deploy AI voice agents for phone calls.

View Retell AI

Synthflow

Voice

No-code platform for AI voice agents that automate phone calls.

View Synthflow

At a glance

Feature comparison of Retell AI and Synthflow
AttributeRetell AISynthflow
CategoryVoiceVoice
PricingFREEMIUMFREEMIUM
LicenseProprietaryProprietary
DeploymentCloudCloud
PlatformsWeb, APIWeb, API
Model supportMulti-modelMulti-model
Vendor (differs)Retell AISynthflow AI

The honest brief

Retell AI

Bring your own LLM behind the voice agent, so it isn't locked to a single model like most all-in-one voice platforms.

  • Inbound and outbound call handling
  • SIP/Twilio telephony built in
  • Low-latency turn-taking model
  • No-code builder plus API
  • Per-minute costs stack with LLM/TTS
  • Voice quality depends on chosen vendors
  • Cloud-only, no self-host

Synthflow

Tuned for high-volume contact-center phone automation, with a choice of LLM and TTS providers per agent.

  • No-code visual flow designer
  • In-house telephony, 200+ integrations
  • Pay-as-you-go, free to build and test
  • Real-time call monitoring
  • Focused on phone/voice, not broad chat
  • Public pricing requires contacting sales
  • Advanced features gated to higher tiers