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GPT-4o Mini TTS

openaiopenai/gpt-4o-mini-tts

Media Generation Capabilities

tts
output_formats
  • mp3
  • opus
  • aac
  • flac
voices
  • alloy
  • ash
  • ballad
  • coral
  • echo
  • fable
  • onyx
  • nova
  • sage
  • shimmer
  • verse
defaults
voice
alloy

API guide

Text-to-speech (streaming)

GPT-4o Mini TTS uses the standard OpenAI speech endpoint. Call it via TheRouter's unified API β€” the model supports synchronous and streaming modes with steerable instructions for tone control.

cURL
curl https://api.therouter.ai/v1/audio/speech \
  -H "Authorization: Bearer $THEROUTER_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "openai/gpt-4o-mini-tts",
    "input": "Welcome to TheRouter β€” your unified API for all AI models.",
    "voice": "nova",
    "instructions": "Speak warmly and professionally, like a friendly customer service agent.",
    "response_format": "mp3"
  }' \
  --output speech.mp3

Streaming TTS

For real-time voice applications, stream audio chunks as they are generated. GPT-4o Mini TTS sends binary audio chunks via SSE, with the first chunk arriving in under 500ms in typical conditions.

cURL
curl https://api.therouter.ai/v1/audio/speech \
  -H "Authorization: Bearer $THEROUTER_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "openai/gpt-4o-mini-tts",
    "input": "This is a streaming voice demo using TheRouter API.",
    "voice": "echo",
    "response_format": "pcm"
  }' \
  --output - | ffplay -f s16le -ar 24000 -ac 1 -
Fact ledger β€” every claim on this page traces here
sourceURLretrieved
Release dateopenai.com β†—2026-05-28verified
Base architectureopenai.com β†—2026-05-28verified
Endpointdevelopers.openai.com β†—2026-05-28verified
Voicesdocs.aimlapi.com β†—2026-05-28verified
Supported languagestokenmix.ai β†—2026-05-28verified
Context windowtokenmix.ai β†—2026-05-28to verify
Output formatsdevelopers.openai.com β†—2026-05-28verified
Steerabilitysimonwillison.net β†—2026-05-28verified
Steerability benchmark (Simon Willison)simonwillison.net β†—2026-05-28verified
Standard TTS benchmarksopenai.com β†—2026-05-28unknown
OpenAI launches gpt-4o-mini-tts alongside new speech-to-text modelsopenai.com β†—2026-05-28verified
What voices are available with gpt-4o-mini-tts?docs.aimlapi.com β†—2026-05-28to verify
How does the instructions parameter work?simonwillison.net β†—2026-05-28to verify
What languages does gpt-4o-mini-tts support?tokenmix.ai β†—2026-05-28to verify
How does pricing work exactly? Token-based vs per-minute?tokenmix.ai β†—2026-05-28to verify
Can I use gpt-4o-mini-tts through TheRouter?api.therouter.ai β†—2026-05-28to verify
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