Sonic-3.6 🧠 Model Freemium

What it is

Sonic is Cartesia's text-to-speech family. It is built on state space models (SSMs) rather than transformers, which makes it very fast. Sonic-3.6, generally available since 27 August 2026, is the current version. Cartesia also makes Ink-2, a streaming speech-to-text model. Cartesia pitches Sonic mainly at real-time voice agents, but it also works for narration and voiceovers.

Key features

• Sub-90 ms latency, built for streaming
• 44 languages, newly including Odia and Urdu, plus expanded Hinglish
• Natural pacing and disfluencies (such as 'uhm') for conversational delivery
• Instant voice cloning (Pro) and professional cloning (Startup and up)
• Volume, speed and emotion controls through API parameters and SSML

Where you can use it

The Cartesia playground and API, plus cloud marketplaces such as AWS SageMaker JumpStart for Sonic 3. We found no creator app in our directory that documents Sonic by name. Most use comes through developer and voice-agent platforms.

Pricing and rights

Cartesia's Free plan gives 20,000 credits a month. Pro costs $5 a month for 100,000 credits and adds a commercial licence and instant voice cloning. Startup costs $49 and adds professional cloning. Scale costs $299. Commercial use starts on Pro.

Who it is for

Developers building voice agents, apps and games, and budget-minded creators who want a cheap commercial licence for narration.

Verdict

Sonic-3.6 is one of the fastest natural-sounding TTS models, and $5 a month is a low price for commercial use. It is built for agents first. There is no long-form editor like ElevenLabs Studio, and there are fewer ready-made creator integrations.