What is Cartesia?
Cartesia is a real-time voice AI platform that provides speech models and managed voice agents for developers building live conversational applications. Cartesia is built on State Space Model architectures, including Mamba and H-Nets, and delivers text-to-speech, speech-to-text, and voice agent tooling through a single API designed for low-latency conversation.
Key Features
- Sonic text-to-speech: A fast, ultra-realistic voice synthesis model that converts text into speech at speeds suitable for live conversation. Sonic is the speech generation layer that voice agents and applications call through the Cartesia API.
- Ink speech-to-text: A streaming transcription model positioned as the fastest and most accurate in the Cartesia lineup. Streaming transcription supports real-time understanding of caller or user speech during a live session.
- Managed Agents: A platform for building and shipping enterprise voice agents, powered by Cartesia's own speech models. Managed Agents is described as the fastest and most customizable way to build voice agents on the platform.
- 44-language support: Cartesia's speech models cover 44 languages, according to the site's meta description, which matters for products serving multilingual users.
- State Space Model research foundation: Cartesia's team pioneered state space models, Mamba, and H-Nets, and the production models run on this architecture for low latency at scale. The research mission centers on AI that learns through real-world interaction.
- Flexible deployment: The same models and agents run across cloud, on-premise, and on-device. Cloud inference uses regional API endpoints for in-region processing, which helps with latency targets, data residency obligations, and compliance frameworks.
- Single API for models and agents: Developers can either build a voice agent or call the speech models directly through the API. The site states that going live takes minutes.
- Voice library and demos: Cartesia offers a voices catalog and interactive demos, including a sample agent named Skylar, so teams can evaluate voice quality before committing.
Use Cases
- Customer support and outbound calling: Teams can deploy voice agents that answer and make calls. EliseAI runs more than 5 million voice calls per month on Cartesia, which illustrates the platform at production scale.
- Real-time transcription pipelines: Developers building live captioning, call analytics, or conversational interfaces can use Ink for streaming speech-to-text rather than batch transcription.
- Voice-enabled applications: Product teams that need lifelike speech output in 44 languages can call Sonic directly through the API without building their own synthesis stack.
- Regulated and latency-sensitive deployments: Organizations with data residency or compliance requirements can run Cartesia models in-region via cloud endpoints, or move to on-premise and on-device deployment.
- Enterprise voice agent programs: Companies that want a customizable agent platform rather than raw model access can build on Managed Agents and contact Cartesia's sales team for rollout guidance.
Who It Is For
Cartesia targets developers and product teams building real-time voice experiences: voice agent developers, AI engineers, and enterprise teams that need production-grade speech synthesis and streaming transcription. It solves the latency and infrastructure problem that makes live voice conversation difficult, by combining speech models and agent tooling in one API and offering deployment options across cloud, on-premise, and on-device. Teams that need multilingual speech output or strict data residency controls are also a fit.
Pricing
Cartesia lists a Pricing page on its site, but the source material does not state specific plans, prices, or whether a free tier exists. Prospective users should check the Pricing page or contact sales for current terms.
Frequently Asked Questions
What is Cartesia used for?
Cartesia is used to build real-time voice AI: production voice agents that answer and make calls, lifelike text-to-speech through the Sonic model, and streaming speech-to-text through the Ink model. Developers access these capabilities through a single API.
Is Cartesia free?
The source material does not state whether Cartesia offers a free tier or trial. Cartesia's site includes a Pricing page and a "Try Cartesia" option, so pricing details should be confirmed there or with the sales team.
What models does Cartesia offer?
Cartesia offers two core speech models: Sonic for text-to-speech and Ink for speech-to-text. On top of these, Cartesia provides Managed Agents, a platform for building voice agents powered by the same models.
How does Cartesia reduce latency for voice applications?
Cartesia runs its models on State Space Model architectures, including Mamba and H-Nets, which the company describes as enabling low latency at scale. Cartesia also offers regional cloud API endpoints so inference runs in-region, keeping applications within their latency envelope.
Can Cartesia be deployed on-premise or on-device?
Yes. Cartesia states that the same models and agents can be deployed across cloud, on-premise, and on-device. This supports data residency obligations and compliance frameworks in addition to latency requirements.
