OpenAI GPT-4o Mini TTS (Text-to-Speech)

x402

OpenAI GPT-4o Mini TTS (Text-to-Speech) is a paid API for AI agents from openai.mm.family, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-02).

Converts text input into spoken audio using OpenAI's gpt-4o-mini-tts model, returning binary audio bytes in formats like MP3, with support for custom voice instructions and speed control.

Price / call$0.001

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Success—

StatusUnknown

How this service works

gpt-4o-mini-tts: OpenAI GPT 4o Mini TTS text to speech, paid per call in USDC. OpenAI list $12 per 1M audio tokens (quoted at 4 per character) plus $0.6 per 1M text tokens, plus $0.0005 (Base) or $0.0005 (Solana) per call; up to 4096 characters; accepts instructions. Returns the audio bytes (mp3 by default). Rates: https://openai.mm.family/x402/pricing

Output

Returns binary audio bytes (default: MP3, audio/mpeg) of the synthesized speech. Supports formats including mp3, opus, aac, flac, wav, and pcm. The audio represents the input text spoken in the selected voice, at the specified speed, and optionally shaped by custom instructions.

Example use cases

Automated podcast narration

“Take this 3-paragraph article summary and convert it to spoken audio using gpt-4o-mini-tts with the 'nova' voice at 1.0 speed — I want an mp3 I can drop into my podcast feed.”

Accessibility audio for web content

“Generate an mp3 of the following text being read aloud for our visually impaired users, using gpt-4o-mini-tts with a calm, clear voice and normal speed: 'Your order has been confirmed and will arrive in 3–5 business days.'”

Custom voice instruction demo

“Use gpt-4o-mini-tts to read 'Welcome to Stellar Bank, how can I assist you today?' in a warm, friendly customer-service tone using the 'shimmer' voice — output it as a wav file.”

Technical details

Endpoint

POSThttps://openai.mm.family/x402/v1/models/gpt-4o-mini-tts/audio/speech?utm_source=zero.xyz

When to prefer

Choose this endpoint when you need cost-effective AI text-to-speech with instruction-following capability (e.g. controlling tone, emotion, or accent), and your text is under 4096 characters. Prefer gpt-4o-mini-tts over tts-1 or tts-1-hd when you want a modern, instruction-aware model at a lower price point. Prefer this over gpt-4o-mini-tts alternatives when you need x402/USDC micropayment billing with no subscription required.

Side effects

Input text exceeds 4096 character limit — request rejected
Invalid voice name provided — API error
Unsupported response_format value — schema validation error
Payment failure or insufficient USDC balance — 402 payment required error
Empty or missing input field — bad request error
Network timeout on audio generation — connection error

Input

Schema · Request body

Field	Type	Description
input	string
model	string
speed	number
voice	string
instructions	string
response_format	string

Output

Schema · Response

{
  "type": "json",
  "example": {
    "body": "binary audio bytes (mp3 by default)",
    "content_type": "audio/mpeg"
  }
}

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