API reference

Synthesize speech from text

POST /v1/audio/speech request, response, and error contract.

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POST /v1/audio/speech

Converts text to speech. Returns audio binary. Available models: kosmik/tts-kokoro-quality, kosmik/tts-piper-fast

Authentication¶

Send Authorization: Bearer $KOSCOMPUTE_API_KEY.

Request¶

Content type: application/json

Field	Type	Required	Description
`model`	string	Yes	See the endpoint guide for behavior and model support.
`input`	string	Yes	Text to synthesize
`voice`	string	No	Voice identifier
`response_format`	string	No	Values: `wav`, `mp3`, `flac`, `opus`, `pcm`.
`speed`	number	No	See the endpoint guide for behavior and model support.

Examples¶

cURL¶

curl https://api.koscompute.com/v1/audio/speech \
  -H "Authorization: Bearer $KOSCOMPUTE_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model":"kosmik/tts-kokoro-quality","input":"Synthetic example.","response_format":"wav"}'

Python¶

import os
import requests

response = requests.post(
    "https://api.koscompute.com/v1/audio/speech",
    headers={"Authorization": f"Bearer {os.environ['KOSCOMPUTE_API_KEY']}"},
    json={
  "model": "kosmik/tts-kokoro-quality",
  "input": "Synthetic example.",
  "response_format": "wav"
},
)
print(response.json())

JavaScript¶

const response = await fetch("https://api.koscompute.com/v1/audio/speech", {
  method: "POST",
  headers: {
    Authorization: `Bearer ${process.env.KOSCOMPUTE_API_KEY}`,
    "Content-Type": "application/json",
  },
  body: JSON.stringify({"model":"kosmik/tts-kokoro-quality","input":"Synthetic example.","response_format":"wav"}),
});
console.log(await response.json());

Responses¶

Status	Meaning
`200`	Audio binary response
`400`	Bad request — invalid parameters or payload
`401`	Invalid or missing API key
`403`	Model not allowed for this API key
`404`	Public model not found
`413`	Request body exceeds the limit
`429`	Rate limit or admission capacity is full. The message states when to retry; vision saturation also reports active/total vision concurrency.
`502`	Invalid or failed upstream response
`503`	No healthy route
`504`	Backend generation timeout
`500`	Internal server error

Next steps¶

Use the endpoint guide for complete workflows, model capability notes, streaming behavior, and retry advice.