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Google modelsaudio generation api

google/gemini-3.1-flash-tts

Gemini 3.1 Flash Tts by Google - convert text to natural-sounding speech with AI. Supports multiple voices, languages, emotions, and speaking styles for content creation and accessibility.

Input
The text to convert to speech. Gemini 3.1 Flash TTS supports natural-language prompting for style, pace, accent, and emotional expression — include delivery instructions inline with the text (e.g. 'Say cheerfully: Have a wonderful day!'). Supports expressive audio tags like [sigh], [laughing], [whispering], [short pause] for fine-grained control over delivery. For multi-speaker synthesis, prefix lines with speaker aliases defined in the speakers field (e.g. 'Alice: Hello!\nBob: Hi!').
Audio output format. mp3: compressed, small file size (recommended). wav: uncompressed PCM wrapped in WAV (24 kHz, 16-bit mono). ogg_opus: Ogg container with Opus codec, good quality-to-size ratio. Allowed values: wav, mp3, ogg_opus.
02
Controls the randomness of the speech output. Higher values produce more creative and varied delivery, while lower values make the output more predictable and focused. Range: 0 to 2.
Multi-speaker voice configuration. When set, enables multi-speaker synthesis where different parts of the text are spoken by different voices. Each speaker needs a voice and a speaker_id (alias) that matches prefixes in the prompt.
Language for multilingual synthesis. When set, steers the model to speak in the specified language. If not set, the model auto-detects the language from the text. Allowed values: Arabic (Egypt), Bangla (Bangladesh), Dutch (Netherlands), English (India), English (US), French (France), German (Germany), Hindi (India), Indonesian (Indonesia), Italian (Italy), Japanese (Japan), Korean (South Korea), Marathi (India), Polish (Poland), Portuguese (Brazil), Romanian (Romania), Russian (Russia), Spanish (Spain), Tamil (India), Telugu (India), Thai (Thailand), Turkish (Turkey), Ukrainian (Ukraine), Vietnamese (Vietnam), Afrikaans (South Africa), Albanian (Albania), Amharic (Ethiopia), Arabic (World), Armenian (Armenia), Azerbaijani (Azerbaijan), Basque (Spain), Belarusian (Belarus), Bulgarian (Bulgaria), Burmese (Myanmar), Catalan (Spain), Cebuano (Philippines), Chinese Mandarin (China), Chinese Mandarin (Taiwan), Croatian (Croatia), Czech (Czech Republic), Danish (Denmark), English (Australia), English (UK), Estonian (Estonia), Filipino (Philippines), Finnish (Finland), French (Canada), Galician (Spain), Georgian (Georgia), Greek (Greece), Gujarati (India), Haitian Creole (Haiti), Hebrew (Israel), Hungarian (Hungary), Icelandic (Iceland), Javanese (Java), Kannada (India), Konkani (India), Lao (Laos), Latin (Vatican City), Latvian (Latvia), Lithuanian (Lithuania), Luxembourgish (Luxembourg), Macedonian (North Macedonia), Maithili (India), Malagasy (Madagascar), Malay (Malaysia), Malayalam (India), Mongolian (Mongolia), Nepali (Nepal), Norwegian Bokmal (Norway), Norwegian Nynorsk (Norway), Odia (India), Pashto (Afghanistan), Persian (Iran), Portuguese (Portugal), Punjabi (India), Serbian (Serbia), Sindhi (India), Sinhala (Sri Lanka), Slovak (Slovakia), Slovenian (Slovenia), Spanish (Latin America), Spanish (Mexico), Swahili (Kenya), Swedish (Sweden), Urdu (Pakistan).
Voice preset for single-speaker synthesis. 30 distinct voices are available. Ignored when speakers is set. Popular choices: Kore (strong, firm female), Puck (upbeat, lively male), Charon (calm, professional male), Zephyr (bright, clear female), Aoede (warm, melodic female). Allowed values: Achernar, Achird, Algenib, Algieba, Alnilam, Aoede, Autonoe, Callirrhoe, Charon, Despina, Enceladus, Erinome, Fenrir, Gacrux, Iapetus, Kore, Laomedeia, Leda, Orus, Pulcherrima, Puck, Rasalgethi, Sadachbia, Sadaltager, Schedar, Sulafat, Umbriel, Vindemiatrix, Zephyr, Zubenelgenubi.
Optional style and delivery instructions prepended to the prompt. Controls expressiveness, accent, pace, tone, and emotional expression using natural language. Use this to separate style control from the text content. Examples: 'Speak warmly and slowly', 'Read this as a dramatic newscast', 'Use a British accent with a cheerful tone', 'Whisper mysteriously'.
Idle

Example output — click Run to generate your own

API README

Gemini 3.1 Flash Tts

google/gemini-3.1-flash-tts turns written content into expressive spoken audio with the speed profile of the Gemini 3.1 Flash family. It follows performance instructions for tone, pacing, emotion, pronunciation, and speaker behavior instead of treating the script as neutral narration. This combination makes the model a practical choice when the creative outcome depends on those qualities rather than on a generic media conversion.

For production work, thirty voice choices, broad automatic or explicit language selection, multi-speaker mapping, and WAV, MP3, or Ogg Opus delivery support both conversational prototypes and finished speech assets. The result is most reliable when the source material and creative brief clearly describe the intended subject, progression, visual or sonic character, and the qualities that must remain unchanged.

Highlights

Expressive instruction following shapes tone, pace, emotion, and speaking style from text.

Multi-speaker synthesis gives named speakers distinct voices within one performance.

Broad multilingual delivery speaks scripts across a large set of supported languages.

Natural prosody produces fluid emphasis and cadence rather than word-by-word reading.

Pricing

Prompt allowancePrice
Each started 1,000 characters$0.150

When to Use

✅ Good fit❌ Consider alternatives
The model's named workflow matches the source material and intended outputA different input modality or model route is required
A managed asynchronous result is suitable for the production pipelineA synchronous, interactive editor is essential
The documented controls cover the required duration, framing, or formatThe project needs controls outside this endpoint's schema
Creative iteration benefits from a repeatable request structureExact deterministic pixels, frames, geometry, or samples are mandatory
A finished downloadable media asset is the desired deliverableEditable source layers or a native project file are required

Prompt Guide

For speech synthesis, state the intended result first, then add the subject or source treatment, progression, style, and delivery constraints. Keep one creative variable per phrase, use the documented field names for controls, and change one setting at a time when comparing results.

{
  "output_format": "mp3",
  "prompt": "I can't believe it worked! [laughing] After all those hours of debugging [sigh] it was just a missing semicolon."
}

Technical Specs

SpecValue
Model IDgoogle/gemini-3.1-flash-tts
Inputslanguage_code, output_format, prompt, speakers, style_instructions, temperature, voice
Required inputsprompt
Output fieldscontent_type, url
ExecutionAsync (submit, then poll for result)
Output Formatwav / mp3 / ogg_opus

Related Models

Related Models

google/lyria-2Lyria 2 is Google's AI audio generation model. Produce high-quality music tracks, sound effects, and audio landscapes from natural language prompts.google/gemini-ttsGemini TTS by Google - convert text to natural-sounding speech with AI. Supports multiple voices, languages, emotions, and speaking styles for content creation and accessibility.