Need help with your APIs? I offer API discovery, governance & evangelism services. Explore services →
API Evangelist API Evangelist
Discovery
Learnings
Guidance
Toolbox
Alignment
API Evangelist LLC

Cartesia Speech-to-Text API

Batch transcription of an audio file of any length.

Cartesia Speech-to-Text API is one of 21 APIs that Cartesia publishes on the APIs.io network, described by a machine-readable OpenAPI specification.

Tagged areas include Speech-to-Text. The published artifact set on APIs.io includes an OpenAPI specification, API documentation, and an API reference.

This API exposes 1 operation across 1 path, and defines 3 schemas. It is described by OpenAPI 3.0.3, at version 2026-03-01.

Requests are made against a single base URL, https://api.cartesia.ai.

1 operations 1 paths 3 schemas 1 POST

Metadata

The identity and technical contract details declared by the specification.

Specification
OpenAPI 3.0.3
API Version
2026-03-01
Base URL
https://api.cartesia.ai
Authentication
HTTP Bearer
Contact
Resource Areas
1

Authentication & Security 1

Cartesia Speech-to-Text API declares 1 security scheme for authenticating requests. It accepts HTTP bearer tokens (sk_car_... API key or short-lived access token) (bearerAuth). By default, every request must be authenticated.

  • bearerAuth — Cartesia API key (skcar...) or a short-lived access token minted via POST /access-token, passed as Authorization: Bearer . Every request also requires the Cart…

Paths & Operations 1

Across 1 path, the API surfaces 1 operation — 1 POST. Each is listed below with its method, path, parameters, and response codes.

Speech-to-Text 1

Batch transcription of an audio file of any length.

POST
/stt
Batch Speech-to-Text
transcribe 3 params body → 200401422

Schemas 3

The contract defines 3 schemas that model the data the API accepts and returns. The most detailed are Error (6 properties), TranscriptResponse (6 properties), WordTiming (3 properties). Each schema is shown below with its type and property counts.

TranscriptResponse
object
6 properties 2 required
WordTiming
object
3 properties
Error
object
6 properties

Specification

The full machine-readable OpenAPI contract behind this narrative.

Source

cartesia-ai-speech-to-text-api-openapi.yml Raw ↑

Other APIs Cartesia publishes across the network.

Cartesia TTS WebSocket API
Cartesia STT WebSocket API
Cartesia Agents API
Cartesia API Keys API
Cartesia Auth API
Cartesia Calls API
Cartesia Datasets API
Cartesia Deployments API
Cartesia Infill API
Cartesia Knowledge Base API
Cartesia Metrics API
Cartesia Phone Numbers API