AI Voice: ElevenLabs & OpenAI TTS API Guide
Transform text into natural-sounding speech with our enterprise-ready Voice Synthesis API. Perfect for developers, content creators, and businesses looking to add professional voice capabilities to their applications. Our API supports leading AI models from ElevenLabs and OpenAI, offering 30+ premium voices, multilingual support, and advanced customization options with enterprise-grade reliability.
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For detailed information about using models with APIpie, check out our Models Overview and Completions Guide.
🎙️ Voice Synthesis Overview
The Voice Synthesis API allows developers to convert text into high-quality speech using state-of-the-art AI models. The API supports both ElevenLabs and OpenAI voice models, providing:
- 30+ premium voices across multiple languages and accents
- Advanced voice customization and style control
- Real-time voice generation with low latency
- Enterprise-grade reliability and scalability
- Comprehensive usage analytics and monitoring
- Secure API access with rate limiting
🎯 Model Comparison and Capabilities
Model Feature Comparison
| Feature | ElevenLabs | OpenAI TTS |
|---|---|---|
| Voice Quality | High fidelity with emotion control | Professional studio quality |
| Language Support | 30+ languages | Primary focus on English |
| Generation Speed | Variable (Flash to Standard) | Consistently fast |
| Customization | Extensive voice settings | Basic voice selection |
| Cost Efficiency | Pay per character | Pay per character |
| Real-time Generation | Yes (with Flash models) | Yes |
| Voice Cloning | Available | Not available |
| Enterprise Support | Yes | Yes |
ElevenLabs Models
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Visit our Models Overview for the most up-to-date list of supported voice models and their capabilities.
| Model | Description | Max Tokens | Provider |
|---|---|---|---|
| eleven_multilingual_v2 | Latest multilingual model with enhanced quality | 5000 | elevenlabs |
| eleven_multilingual_v1 | First generation multilingual model | 5000 | elevenlabs |
| eleven_monolingual_v1 | English-optimized model | 5000 | elevenlabs |
| eleven_turbo_v2 | Fast generation model | 5000 | elevenlabs |
| eleven_turbo_v2_5 | Enhanced turbo model | 5000 | elevenlabs |
| eleven_flash_v2 | Ultra-fast generation | 5000 | elevenlabs |
| eleven_flash_v2_5 | Latest ultra-fast model | 5000 | elevenlabs |
OpenAI Models
| Model | Description | Provider |
|---|---|---|
| tts-1-hd | High-definition voice models | openai |
| tts-1-1106 | Standard voice models | openai |
🗣️ Available Voices
Technical Specifications
| Specification | Details |
|---|---|
| Audio Format | MP3, WAV |
| Sample Rate | 16kHz - 48kHz |
| Bit Depth | 16-bit, 24-bit |
| Channels | Mono, Stereo |
| Latency | 200ms - 2000ms |
| Max Input Length | 5000 tokens |
| Rate Limiting | Yes (configurable) |
ElevenLabs Voices
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Browse more voices in the ElevenLabs Voice Library
Professional Narration
- Rachel: Young female, American accent, calm tone - ideal for narration
- Drew: Middle-aged male, American accent - perfect for news reading
- Antoni: Young male, American accent - well-rounded narrator
- Thomas: Young male, American accent - calm meditation voice
- Bill: Older male, American accent - trustworthy narration
Character Voices
- Clyde: Middle-aged male, American accent - war veteran character
- Dave: Young male, British-Essex accent - conversational gaming voice
- Fin: Older male, Irish accent - sailor character
- Glinda: Middle-aged female, American accent - witch character
- Charlotte: Young female, Swedish accent - seductive character
News & Media
- Paul: Middle-aged male, American accent - ground reporter
- Sarah: Young female, American accent - soft news voice
- Daniel: Middle-aged male, British accent - authoritative news
- Alice: Middle-aged female, British accent - confident news
- Joseph: Middle-aged male, British accent - field reporter
OpenAI Voices
HD Voices
- Shimmer: Clear and expressive
- Alloy: Versatile and balanced
- Echo: Warm and natural
- Fable: Engaging storyteller
- Onyx: Deep and authoritative
- Nova: Bright and energetic
📝 API Parameters and Configuration
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For detailed API documentation and integration guides, visit our API Reference.
Required Parameters
- model: The AI model to use for voice generation
- voice: The specific voice to use
- input: The text to convert to speech
Optional Parameters (ElevenLabs)
- stability (0-1): Controls voice stability
- similarity_boost (0-1): Enhances similarity to the original voice
- style (0-1): Adjusts speaking style intensity
- use_speaker_boost (boolean): Enhances speaker clarity
💡 Example API Calls
ElevenLabs Example
curl -X POST 'https://apipie.ai/v1/audio/speech' \
-H 'Content-Type: application/json' \
-H 'Authorization: Bearer YOUR_API_KEY' \
--data-raw '{
"model": "eleven_multilingual_v2",
"voice": "Rachel",
"input": "Hello! This is a test of the ElevenLabs text to speech API.",
"voice_settings": {
"stability": 0.5,
"similarity_boost": 0.75
}
}'
OpenAI Example
curl -X POST 'https://apipie.ai/v1/audio/speech' \
-H 'Content-Type: application/json' \
-H 'Authorization: Bearer YOUR_API_KEY' \
--data-raw '{
"model": "tts-1-hd",
"voice": "shimmer",
"input": "Hello! This is a test of the OpenAI text to speech API."
}'
📊 Response Examples
ElevenLabs Response
{
"created": 1729535643,
"audio": {
"content_type": "audio/mpeg",
"url": "https://example.com/generated-audio.mp3"
},
"usage": {
"text_characters": 57,
"cost": 0.004275,
"latency_ms": 1200
}
}
OpenAI Response
{
"created": 1729535643,
"audio": {
"content_type": "audio/mpeg",
"url": "https://example.com/generated-audio.mp3"
},
"usage": {
"text_characters": 52,
"cost": 0.003500,
"latency_ms": 800
}
}
🎯 Common Use Cases
-
Content Creation
- Audiobook production
- Podcast generation
- Video narration
- E-learning content
-
Entertainment
- Game character voices
- Animation dubbing
- Interactive storytelling
- Voice-enabled NPCs
-
Business Applications
- IVR systems
- Virtual assistants
- Customer service
- Corporate training
-
Accessibility
- Screen readers
- Text-to-speech for visually impaired
- Language learning tools
- Reading assistance
⚡ Best Practices
-
Model Selection
- Use multilingual models for multiple language support
- Use turbo/flash models for faster generation
- Use HD models for highest quality output
-
Voice Selection
- Choose voices based on use case
- Consider accent and age appropriate for content
- Test multiple voices to find the best fit
-
Text Preparation
- Use punctuation to control pacing
- Break long text into natural segments
- Include phonetic spelling for unusual words
-
Performance Optimization
- Cache frequently used audio
- Implement proper error handling
- Monitor usage and costs
⚠️ Error Handling
Common errors and solutions:
{
"error": {
"code": "invalid_voice",
"message": "The specified voice is not available for this model."
}
}
Solution: Verify voice compatibility with chosen model.
{
"error": {
"code": "text_too_long",
"message": "Input text exceeds maximum length for selected model."
}
}
Solution: Break text into smaller segments.
🔒 Security and Ethics
- Voice generation requires responsible use
- Implement appropriate content filtering
- Monitor for potential misuse
- Secure API access and authentication
- Respect voice rights and permissions