Ultra-low latency streaming voice API with recurring monthly developer credits.
Verified free allowance
Free tier includes 20,000 model credits each month plus $1 in Line voice agent credits for prototyping and personal use.
Cartesia builds the Sonic voice synthesis engine, optimized for conversational AI agents and real-time streaming audio with sub-100ms latency. The Free tier provides recurring monthly model credits and voice agent credits for evaluation and personal projects.
The industry benchmark for real-time conversational voice synthesis, offering a no-cost entry point for developers testing low-latency voice agents.
Paid plans: Pro and enterprise plans offer higher credit limits, instant voice cloning, concurrency scaling, and commercial licensing.
These links support the important free-offer claims on this page.
Cartesia offers a $0 Free tier with 20,000 model credits per month and $1 in agent credits with no credit card required to start.
Cartesia documents its Sonic text-to-speech engine, streaming audio latency, and usage limits across Free and Pro tiers.
