Text-to-speech playground

GPT-4o mini TTS API

OpenAI low-latency, steerable text-to-speech.

GPT-4o mini TTS is a text-to-speech model from OpenAI, available on OttoPort's OpenAI-compatible API as the model ID gpt-4o-mini-tts at $13.80 / 1M characters as of 2026-10-14.

Provider

OpenAI

Price

$13.80 / 1M characters

Model ID

gpt-4o-mini-tts

Type

text-to-speech model

VoiceoversProduct narrationConversational audio

Create with GPT-4o mini TTS

tts

ScriptVoice (optional)

Your result appears here

Start with the example prompt or make it your own. Your OttoPort account is used securely for generation.

Pricing

GPT-4o mini TTS API pricing

What OttoPort bills for GPT-4o mini TTS, and what that works out to per unit. Rates are read from the same catalog the gateway meters against, and were current on 2026-10-14.

Per 1M characters	$13.80
1,000 characters	$0.0138	roughly 150 spoken words
A 500-word script	$0.038	about 2,750 characters
Characters per $1	72,463

No subscription and no minimum — OttoPort bills prepaid credits against usage. See the full rate card.

Quickstart

Call GPT-4o mini TTS in three lines

Send "model": "gpt-4o-mini-tts" to POST https://ottoport.ai/api/v1/audio/speech with an OttoPort key. No OpenAI account, no waitlist, no separate SDK.

curl https://ottoport.ai/api/v1/audio/speech \
  -H "Authorization: Bearer $OTTOPORT_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "gpt-4o-mini-tts",
    "input": "Welcome to OttoPort.",
    "format": "mp3"
  }' --output speech.mp3

import requests

audio = requests.post(
    "https://ottoport.ai/api/v1/audio/speech",
    headers={"Authorization": "Bearer " + API_KEY},
    json={"model": "gpt-4o-mini-tts", "input": "Welcome to OttoPort.", "format": "mp3"},
)
open("speech.mp3", "wb").write(audio.content)

const res = await fetch("https://ottoport.ai/api/v1/audio/speech", {
  method: "POST",
  headers: {
    Authorization: `Bearer ${API_KEY}`,
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    model: "gpt-4o-mini-tts",
    input: "Welcome to OttoPort.",
    format: "mp3",
  }),
});
const buffer = Buffer.from(await res.arrayBuffer());

Before you start

1. Create a key at /api-keys.
2. Top up credits — the smallest pack is $25.
3. Paste the request. It returns on the same request.

Full reference at /docs, or drive it from an agent with the MCP server and CLI.

Reference

Request parameters

The body POST https://ottoport.ai/api/v1/audio/speech accepts for GPT-4o mini TTS.

Field	Type	Required	Notes
model	string	Yes	Always gpt-4o-mini-tts for GPT-4o mini TTS.
input	string	Yes	Text to speak. Characters are the billed unit.
voice	string	No	Provider voice identifier.
format	string	No	Audio container, e.g. `mp3`.

Comparison

GPT-4o mini TTS direct vs through OttoPort

GPT-4o mini TTS is the same model either way — what changes is how many accounts, keys, and integrations you carry to reach it.

	OpenAI direct	Via OttoPort
Accounts and keys	An OpenAI account, plus one more for every other model you add	One OttoPort account and one key for the whole catalog
Request shape	OpenAI's own SDK and response format	OpenAI-compatible — point baseURL at OttoPort and change the model string
Switching models	A new integration per provider	Replace gpt-4o-mini-tts with any other model ID in the catalog
Billing	A separate invoice and contract per provider	Prepaid credits, no subscription, one usage ledger
Provider outages	Your call fails	Configured backup routes are tried in order on provider failure

Write for the ear, not the page.

Use punctuation to guide pauses.

Keep each generation focused on one tone.

FAQ

GPT-4o mini TTS API questions

Cost, keys, and model IDs for GPT-4o mini TTS on OttoPort.

How much does the GPT-4o mini TTS API cost?

On OttoPort, GPT-4o mini TTS costs $13.80 / 1M characters as of 2026-10-14. For scale, a 500-word script: $0.038. Billing is prepaid usage with no subscription and no minimum, and the current rate is always published at ottoport.ai/pricing.

How do I get a GPT-4o mini TTS API key?

You do not need an OpenAI key. Create an OttoPort account, generate a key at ottoport.ai/api-keys, and send it as "Authorization: Bearer <key>" to POST https://ottoport.ai/api/v1/audio/speech with "model": "gpt-4o-mini-tts". The same key reaches every other model in the catalog.

What is the model ID for GPT-4o mini TTS?

The OttoPort model ID for GPT-4o mini TTS is gpt-4o-mini-tts. Pass it as the model field on POST https://ottoport.ai/api/v1/audio/speech, or list it programmatically from GET https://ottoport.ai/api/v1/models.

Do I need an OpenAI account to use GPT-4o mini TTS?

No. OttoPort connects to OpenAI on your behalf, so one OttoPort account covers GPT-4o mini TTS and every other model in the catalog — no per-provider contracts, keys, or invoices.

Alternatives

Other text-to-speech models on the same API

Same endpoint, same key — swapping model is a one-string change from gpt-4o-mini-tts.

MiniMax Speech 2.8 Turbo API

MiniMax

$72.79 / 1M characters

MiniMax Speech 2.8 HD API

MiniMax

$121.32 / 1M characters

Seed Audio 1.0 API

ByteDance

$0.329 / request

ElevenLabs v3 API

ElevenLabs

$103.50 / 1M characters

Gemini 2.5 Flash TTS API

Google

$11.50 / 1M characters

ElevenLabs Turbo 2.5 API

ElevenLabs

$51.75 / 1M characters

Browse the full catalog — every model with its provider and per-unit price.