Cartesia vs Inworld AI
Cartesia's Sonic 3.6 rates higher than every Inworld AI model.
Sierra, Decagon, and Quora run their production voice agents on Cartesia. One model, 40+ languages, first audio in under 90ms.
Provider Voice Arena Elo
Higher is better
Voice quality
Cartesia rates first on independent blind listening tests
- Cartesia's Sonic 3.6 ranks first of the 94 models on Artificial Analysis's Provider Voice Arena.
- Every Inworld AI Realtime TTS model rates below it.
Reasons why companies choose Cartesia over Inworld AI
Human-like naturalness
Intonation, pacing, pronunciation, emotion, and audio quality that drive higher completion rates
Cartesia1282 EloAugust 2026
Inworld AI1199 EloRealtime TTS 1.5 Max1187 EloRealtime TTS-21134 EloRealtime TTS 1.5 MiniAugust 2026
Languages
Comprehension and trust across a global customer base.
Cartesia40+ production languages from one model, best-in-class quality on each oneInworld AI15 production languages. Everything past that is experimental.Model maturity
Whether the model you benchmark is the model you can ship on.
CartesiaSonic 3.5 is generally available, on the public API, on every tierInworld AITheir highest-scoring model is a research previewDeployment
Decides whether regulated teams can use it at all.
CartesiaOn-prem and air-gapped, already running at government, healthcare, and financial institutions, behind a 99.9% uptime SLAInworld AIOn-prem, SLA, DPA, and data residency are Enterprise-tier onlyCustom voices
How much audio you have to collect before a custom voice is usable.
Cartesia3 seconds of audioInworld AI5 to 15 seconds of reference audioEnd-to-end stack
How many vendors it takes to run one call.
CartesiaTTS, STT, and Agents from one vendor, on one API. The only provider ranked first on both speech and transcriptionInworld AITTS, STT, and a realtime router
Frequently asked questions
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