Text to speech | Respan Docs

Convert text to speech through the Respan gateway with automatic logging.

Authentication

AuthorizationBearer

Use your Respan API key for Respan API authentication. Enter only the Respan API key value; clients send Authorization: Bearer <RESPAN_API_KEY>. For /api/responses, OpenAI or Azure OpenAI provider credentials go in Settings -> Providers or the request body credential_override field, not in this auth field.

Headers

X-Data-Respan-ParamsstringOptional

Base64-encoded JSON object of Respan parameters. Legacy X-Data-Keywordsai-Params is still accepted.

Request

This endpoint expects an object.

modelenumRequired

TTS model.

Allowed values:

inputstringRequired

Text to generate audio for. Max 4096 characters.

voiceenumRequired

Voice to use.

response_formatenumOptionalDefaults to mp3

Audio output format.

speeddoubleOptionalDefaults to 1

Audio speed (0.25 to 4.0).

customer_credentialsobjectOptional

Per-customer LLM provider credentials.

disable_logbooleanOptionalDefaults to false

When true, omits input/output from the log. Metrics still recorded.

metadataobjectOptional

Custom key-value metadata.

customer_identifierstringOptional

End user identifier.

thread_identifierstringOptional

Conversation thread ID.

Response

Audio content in the requested format.

Errors

401

Unauthorized Error

$	curl -X POST https://api.respan.ai/api/audio/speech \
>	-H "Authorization: Bearer <respanApiKey>" \
>	-H "Content-Type: application/json" \
>	-d '{
>	"model": "tts-1",
>	"input": "Hello, how are you?",
>	"voice": "alloy"
>	}'