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
At a glance
| Attribute | Retell AI | Synthflow |
|---|---|---|
| Category | Voice | Voice |
| Pricing | FREEMIUM | FREEMIUM |
| License | Proprietary | Proprietary |
| Deployment | Cloud | Cloud |
| Platforms | Web, API | Web, API |
| Model support | Multi-model | Multi-model |
| Vendor (differs) | Retell AI | Synthflow AI |
| Capabilities (differs) |
|
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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
When to pick which
Both cover Voice agent.
Pick Retell AI if you need Tool / function calling and AI app builder.
- Tool / function calling (secondary capability)
- AI app builder (primary capability)
Pick Synthflow if you need Workflow orchestration, Calendar scheduling, and CRM automation.
- Workflow orchestration (primary capability)
- Calendar scheduling (secondary capability)
- CRM automation (secondary capability)