OpenAI TTS - Text-to-Speech

Cloud-based Text-to-Speech API O AI Processing & RAG

Basic Information

Product Description

OpenAI TTS is a text-to-speech API service provided by OpenAI, offering multiple high-quality preset voices and multilingual output. The gpt-4o-mini-tts model, launched in 2025, introduces enhanced steerability, allowing developers to control speech styles through instructions, supporting 13+ preset voices and various audio output formats. When combined with OpenAI's STT and GPT models, it enables the creation of complete voice dialogue systems.

Core Features/Characteristics

  • Three Model Options:
  • TTS Standard: Cost-effective standard quality
  • TTS HD: High-definition audio, more natural speech
  • gpt-4o-mini-tts: Latest multimodal model with instruction control
  • 13+ Preset Voices: Alloy, Ash, Ballad, Coral, Echo, Fable, Nova, Onyx, Sage, Shimmer, Verse, etc.
  • Steerability: gpt-4o-mini-tts supports describing speech styles through instructions
  • Multi-format Output: MP3, Opus, AAC, FLAC, WAV, PCM
  • Real-time Streaming: Supports real-time audio stream output
  • Multilingual Support: Automatically adapts to the language of the input text

Business Model

  • TTS Standard: $15 per million characters
  • TTS HD: $30 per million characters
  • gpt-4o-mini-tts: Input $0.60 per million tokens + Audio output $12 per million tokens
  • Free Quota: $5 free quota for new accounts (no credit card required)

Target Users

  • Developers needing voice output for applications
  • Teams building voice assistants and chatbots
  • Accessibility application developers
  • Content creators (audiobooks, podcasts, etc.)
  • Education and language learning applications

Competitive Advantages

  • Deep integration with OpenAI GPT and STT ecosystem
  • Unique steerability feature of gpt-4o-mini-tts
  • High-quality preset voices, no additional training required
  • Simple and developer-friendly API
  • Transparent pricing, no hidden fees

Competitive Disadvantages

  • Does not support voice cloning
  • Limited variety of preset voices
  • Emotional expressiveness not as strong as ElevenLabs v3

Relationship with OpenClaw Ecosystem

OpenAI TTS is the foundational choice for voice output on the OpenClaw platform, working alongside Whisper STT and GPT series models to form a complete OpenAI voice dialogue stack. The instruction steerability of gpt-4o-mini-tts allows OpenClaw to customize speech styles for different agent roles (e.g., polite customer service tone, concise assistant style) without additional training, enabling personalized voice output.