Cartesia vs PolyAI
A side-by-side comparison of capabilities, autonomy, integrations, and pricing to help you choose.
Short answer: choose Cartesia if you want low-latency voice ai models and a platform for real-time voice agents (Assistant, freemium); choose PolyAI if you want enterprise voice ai agents that answer and resolve customer calls (Supervised agent, usage).
| Cartesia | PolyAI | |
|---|---|---|
| What it is | Low-latency voice AI models and a platform for real-time voice agents | Enterprise voice AI agents that answer and resolve customer calls |
| Type | platform | platform |
| Autonomy | Assistant | Supervised agent |
| Pricing | freemium · Free (20K credits/mo); Pro $5/mo | usage |
| Best for | developers, enterprise | enterprise, mid-market |
| Deployment | saas, api, self-hosted, on-prem | saas, api |
| Modalities | text, voice, api, code | voice, text, api |
| Models | proprietary | proprietary |
| Protocols | rest-api, function-calling | mcp, rest-api, function-calling |
| Integrations | LiveKit, Twilio, Pipecat, Vapi | Five9, NICE CXone, Twilio, Amazon Connect, Genesys, Salesforce |
| Capabilities | 4 documented | 4 documented |
Cartesia
- +Genuinely differentiated state-space-model tech with best-in-class latency and on-device efficiency
- +Full stack (TTS, STT, cloning, and the Line agent platform) plus deep ecosystem integrations and self-hosted/VPC options
- +Strong technical credibility and capital, including NVIDIA backing
- -Younger and less battle-tested than ElevenLabs and Deepgram; the Line agent platform is barely a year old
- -Closed, proprietary models (no open weights for production Sonic/Ink), creating lock-in
PolyAI
- +Strong, natural voice quality proven on hard and regulated call types
- +Deep CCaaS and CRM integration plus a proprietary model stack with enterprise compliance
- +Real enterprise traction and NVIDIA backing
- -Opaque, high-floor pricing inaccessible to SMBs
- -Historically heavy managed-service implementation; the self-serve story is newer
Which should you choose?
Cartesia is low-latency voice ai models and a platform for real-time voice agents, best for developers, enterprise. PolyAI is enterprise voice ai agents that answer and resolve customer calls, best for enterprise, mid-market. The right choice depends on the autonomy level you want, your existing integrations, and your budget, all compared above.