Zonos v0.1 Transformer

The pure-transformer Zonos variant — same voice coverage, different architecture.

POST/v1/media/queue

$0.0148/1K chars

Overview

Zonos v0.1 Transformer is Zyphra's pure-transformer text-to-speech model. It offers the same American and British English voice coverage as the Hybrid variant at the same price; pick whichever produces the delivery you prefer for your copy.

Property	Value
Model ID	`zyphra/zonos-v0.1-transformer`
Alias	`zonos-transformer`
Upstream Model	`zyphra/zonos-v0.1-transformer`
Category	Text to Speech
Languages	English (American and British accents)
Output	`mp3` (default) or `pcm`
Pricing	$0.0148 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: 'zyphra/zonos-v0.1-transformer',
    prompt: 'Your text to speak goes here.',
    options: { voice: 'american_female' },
  }),
});
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": "zyphra/zonos-v0.1-transformer", "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.mp3', Buffer.from(job.result.audio.base64, 'base64'));

Request Body

Parameter	Type	Required	Description	Default
`model`	`string`	Yes	`zyphra/zonos-v0.1-transformer`	—
`prompt`	`string`	Yes	The text to speak (max 50,000 bytes)	—
`options.voice`	`string`	No	Voice identifier	`american_female`
`options.outputFormat`	`string`	No	`mp3` (default) or `pcm`	`mp3`
`options.speed`	`number`	No	Playback speed multiplier. Honoured only by models that support it	`1.0`

Voices

american_female is used when options.voice is omitted. 5 voices available:

american_female
american_male
british_female
british_male
random

Features

Same voice coverage as Zonos Hybrid
Pure transformer architecture
American and British accents, male and female
random voice for varied batch output

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

Zonos v0.1 Transformer

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