Type
Spec
Rate
Input
per 1M prompt tokens
$2.60
Output
per 1M generated tokens
$52.00
Gemini 3.1 Flash TTS and Gemini 2.5 Flash TTS side by side: specs, capabilities, parameters, and live pricing from the EmpirioLabs catalog.
Google Audio GenerationGemini 3.1 Flash TTS and Gemini 2.5 Flash TTS are both Google models in the Audio Generation category, available through the EmpirioLabs API.
| Spec | Gemini 3.1 Flash TTS | Gemini 2.5 Flash TTS |
|---|---|---|
| Model ID | gemini-3-1-flash-tts | gemini-2-5-flash-tts |
| Author | ||
| Released | Apr 13, 2026 | May 20, 2025 |
| Max output | 19,661 tokens | 19,661 tokens |
| Input | Text | Text |
| Output | Audio | Audio |
| Endpoints | POST /v1/audio/speech | POST /v1/audio/speech |
| Capabilities |
Live rates from the EmpirioLabs catalog for both models. Each rate card always matches what the API charges.
Request parameters each model lists on EmpirioLabs, with the allowed values or range where one applies. A dash marks a parameter the model does not list.
| Parameter | Gemini 3.1 Flash TTS | Gemini 2.5 Flash TTS |
|---|---|---|
| input | string | string |
| mode | single, multi Default: single | single, multi Default: single |
| language | string Default: en-US | string Default: en-US |
| voice | Zephyr, Puck, Charon, Kore, Fenrir, Leda, Orus, Aoede, Callir... Default: Charon | Zephyr, Puck, Charon, Kore, Fenrir, Leda, Orus, Aoede, Callir... Default: Charon |
| voice2 | Zephyr, Puck, Charon, Kore, Fenrir, Leda, Orus, Aoede, Callir... Default: Kore | Zephyr, Puck, Charon, Kore, Fenrir, Leda, Orus, Aoede, Callir... Default: Kore |
| speaker1_name | string Default: Speaker1 | string Default: Speaker1 |
| speaker2_name | string Default: Speaker2 | string Default: Speaker2 |
| output_format | WAV, MP3, OGG, ALAW, MULAW Default: WAV | WAV, MP3, OGG, ALAW, MULAW Default: WAV |
| speed | 0.25 to 2 Default: 1 | 0.25 to 2 Default: 1 |
| volume_gain | -96 to 16 Default: 0 | -96 to 16 Default: 0 |
| sample_rate | 8000, 16000, 22050, 24000, 44100, 48000 Default: 24000 | 8000, 16000, 22050, 24000, 44100, 48000 Default: 24000 |
| style_prompt | string | string |
Most controllable Gemini TTS to date.
Inline audio tags (control delivery)
Gemini 3.1 Flash TTS serves speech through POST /v1/audio/speech and returns playable audio. Send the text to speak as input with the model id gemini-3-1-flash-tts. Both models are called through the same endpoint. Set model to gemini-3-1-flash-tts or gemini-2-5-flash-tts. Get an API key from the EmpirioLabs dashboard.
curl https://api.empiriolabs.ai/v1/audio/speech \
-H "Authorization: Bearer $EMPIRIOLABS_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"model": "gemini-3-1-flash-tts",
"input": "Welcome to EmpirioLabs. Your build just finished."
}' \
--output speech.mp3Gemini 3.1 Flash TTS is the newer release (Apr 13, 2026); Gemini 2.5 Flash TTS was released on May 20, 2025. Gemini 2.5 Flash TTS lists the lower rate for Input (per 1M prompt tokens) and Output (per 1M generated tokens). The specs, rate cards, and parameters on this page come from the live EmpirioLabs catalog.
Gemini 3.1 Flash TTS is the newer release (Apr 13, 2026); Gemini 2.5 Flash TTS was released on May 20, 2025.
Gemini 2.5 Flash TTS lists the lower rate for Input (per 1M prompt tokens) and Output (per 1M generated tokens). Both live rate cards are on this page and always match what the API charges.
Yes. Both models use POST /v1/audio/speech with the same EmpirioLabs API key, so most integrations switch by changing the model value. Check the parameters table on this page first if you rely on a model-specific parameter.
Yes. Open each model in the EmpirioLabs playground and run the same prompt on both, with the parameters the API exposes.
Check out our pricing or reach out if you want your own model deployed on our stack.