Cartesia Voice Agent stack

by Cartesia

Cartesia's Sonic TTS plus partner ASR/LLM for low-latency voice agents.

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TL;DR

Best for developers prioritizing sub-100ms TTS first-byte latency in agents. Pricing: see vendor pricing.

Category
Transcription APIs
License
—
Stars
—
Last push
—
Pricing
see vendor pricing
Platforms
Cloud, API

What it is

Cartesia ships the Sonic family of state-space TTS models claimed to deliver sub-100ms first-audio latency. Combined with Deepgram or AssemblyAI ASR plus an LLM, Cartesia powers a popular low-latency voice-agent stack widely deployed in Pipecat, LiveKit Agents, and Vapi configurations.

Best for: Developers prioritizing sub-100ms TTS first-byte latency in agents.
Watch out for: TTS-led; needs paired ASR and LLM providers.

Features

Speaker diarizationNo
Word-level timestampsNo
Streaming / real-timeNo
Languages supportedNone
HIPAA eligibleNo

Cartesia Voice Agent stack vs Whipscribe

FeatureCartesia Voice Agent stackWhipscribe
CategoryTranscription APIsTranscription APIs
PricingNot verified$4–$24 one-time packs (credits never expire) · $2 single unlock · 60 min free on signup
Speaker diarizationNot verifiedYes
Word timestampsNot verifiedYes
StreamingNot verifiedNo
Languages—99
PlatformsCloud, APIWeb, API, MCP

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