# Sonic 3 (Cartesia) — API pricing and providers

> Low-latency text to speech. Model id `cartesia/sonic-3`. Audio model by Cartesia.

- Page: https://infro.io/models/cartesia/sonic-3
- Vendor: Cartesia (https://infro.io/models/cartesia)
- Modality: Audio
- Endpoint through INFRO: `POST /v1/audio/speech` at https://api.infro.io/v1
- List rate: $55 per 1M characters
- Rates checked: 2026-10-05

Rates are Cartesia's published list price: what the customer's own provider account bills, not an INFRO charge. INFRO is a BYOK control plane; it charges a software subscription and adds 0% to model spend.

## Providers that serve it

| Provider | Model id sent |
| --- | --- |
| Together AI | `cartesia/sonic-3` |

## Questions

### How much does the Sonic 3 API cost?

Cartesia's published list rate for Sonic 3 is $55 per 1M characters (checked 2026-10-05). The provider account you connect bills you at the rate on that account, so a negotiated rate replaces the list rate. INFRO adds 0% to model spend.

### Which providers serve Sonic 3?

In INFRO's provider registry, Sonic 3 can be served by Together AI. You connect your own account with any of them, and INFRO routes and fails over between the ones you connect.

### What is the Sonic 3 model ID?

Request it from INFRO as "cartesia/sonic-3". INFRO sends each provider its own id: Together AI "cartesia/sonic-3".

### How do I call Sonic 3 through an OpenAI-compatible API?

Point an OpenAI SDK, or any HTTP client, at https://api.infro.io/v1 with an INFRO gateway key and send model "cartesia/sonic-3" to POST /v1/audio/speech. INFRO runs the request on a provider account you connected and returns the provider's response with an estimated cost.

### Does INFRO mark up Sonic 3 usage?

No. Cartesia or the provider you connect bills model usage to your own account. INFRO charges a software subscription for routing, failover, observability, budgets and policy, and takes 0% of model spend.