Synthesize

Routes the request to the best TTS provider for your intent, with automatic failover. Returns binary audio. The `Content-Type` header (mirrored in `X-Speko-Audio-Format`) tells you the format.

Authorization

bearerAuth

AuthorizationBearer <token>

In: header

Request Body

application/json

TypeScript Definitions

Use the request body type in TypeScript.

text*string

Length1 <= length <= 50000

intent*

voice?string

Provider-specific voice id. Speko falls back to a sane default per provider when omitted.

model?string

Optional upstream model name (e.g. eleven_multilingual_v2, sonic-2, gpt-4o-mini-tts, qwen3-tts-flash). When set, overrides the selector's chosen model on the primary candidate only — failover candidates still use the selector's model so a model intended for provider A is not sent to provider B.

Length1 <= length <= 128

speed?number

Range0.5 <= value <= 2

constraints?

Response Body

`application/octet-stream`

`application/json`

"string"

{
  "error": "Invalid request body",
  "code": "VALIDATION_ERROR"
}

{
  "error": "Unauthorized",
  "code": "UNAUTHORIZED"
}

{
  "error": "All providers failed",
  "code": "SYNTHESIZE_FAILED"
}

Authorization

Request Body

Response Body

200application/octet-stream

400application/json

401application/json

500application/json

`application/octet-stream`

`application/json`

`application/json`

`application/json`