Gemini 3.8 Flash TTS

Google's successor to Gemini 3.1 Flash TTS — the creative tier of the 3.8 TTS family, 30 voices.

POST/v1/media/queue

$0.0527/1K chars

Overview

Gemini 3.8 Flash TTS is a text-to-speech model from Google and the successor to Gemini 3.1 Flash TTS. It is the creative tier of the Gemini 3.8 TTS family, with 30 named voices, and returns raw PCM at 24 kHz.

Property	Value
Model ID	`google/gemini-3.8-flash-tts`
Alias	`gemini-3-8-tts`
Upstream Model	`google/gemini-3.8-flash-tts`
Category	Text to Speech
Output	`pcm` only
Pricing	$0.0527 per 1,000 characters

Usage

All media models use the async job queue. Submit a job, then poll for the result.

Step 1: Submit Job

const res = await fetch('https://api.yepapi.com/v1/media/queue', {
  method: 'POST',
  headers: {
    'x-api-key': 'YOUR_API_KEY',
    'Content-Type': 'application/json',
  },
  body: JSON.stringify({
    model: 'google/gemini-3.8-flash-tts',
    prompt: 'Your text to speak goes here.',
    options: { voice: 'Zephyr' },
  }),
});
const { data } = await res.json();
// data.jobId — use this to poll for results

curl -X POST https://api.yepapi.com/v1/media/queue \
  -H "x-api-key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model": "google/gemini-3.8-flash-tts", "prompt": "Your text to speak goes here."}'

Step 2: Poll for Result

const status = await fetch(`https://api.yepapi.com/v1/media/status/${data.jobId}`, {
  headers: { 'x-api-key': 'YOUR_API_KEY' },
});
const { data: job } = await status.json();
// job.status — "pending" | "processing" | "completed" | "failed"
// job.result.audio — { mimeType, base64 } when completed

curl https://api.yepapi.com/v1/media/status/JOB_ID \
  -H "x-api-key: YOUR_API_KEY"

Write the audio to a file:

import { writeFileSync } from 'node:fs';

writeFileSync('speech.pcm', Buffer.from(job.result.audio.base64, 'base64'));

Request Body

Parameter	Type	Required	Description	Default
`model`	`string`	Yes	`google/gemini-3.8-flash-tts`	—
`prompt`	`string`	Yes	The text to speak (max 50,000 bytes)	—
`options.voice`	`string`	No	Voice identifier	`Zephyr`
`options.outputFormat`	`string`	No	`pcm` only	`pcm`
`options.speed`	`number`	No	Playback speed multiplier. Honoured only by models that support it	`1.0`

Voices

Zephyr is used when options.voice is omitted. 30 voices available (10 of 30 shown):

Zephyr
Puck
Charon
Kore
Fenrir
Leda
Orus
Aoede
Callirrhoe
Autonoe

Features

Successor to Gemini 3.1 Flash TTS
Creative tier of the Gemini 3.8 TTS family
30 named voices
Returns raw PCM only (see the note below)

Warning

This model returns raw PCM only — requesting outputFormat: "mp3" is rejected at submit time. job.result.audio.mimeType carries the sample rate, e.g. audio/pcm;rate=24000;channels=1, and the audio is headerless: wrap it in a WAV container or feed it to an audio pipeline directly.

Billing

Speech is billed on the length of the input text, in UTF-8 bytes — for English text one byte is one character. The cost is known before synthesis starts, so the balance check at submit time quotes the exact final charge. Jobs have a $0.01 minimum.

Under the Hood

Gemini 3.8 Flash TTS

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