Gemini 3.8 Flash-Lite TTS API

About Gemini 3.8 Flash-Lite TTS

Cost-efficient speech for voice agents and dubbing, with streaming, vocal tags, and two-speaker dialogue across 101 languages and 2,000+ voices.

Also known as Gemini Flash-Lite TTS, Google Gemini 3.8 Flash-Lite TTS, Gemini-3.8-Flash-Lite-TTS

Gemini 3.8 Flash-Lite TTS specs

Model ID

gemini-3-8-flash-lite-tts

Author

Google

Category

Audio Generation

Released

Sep 22, 2026

Input

Text

Output

Audio

Endpoints

POST/v1/audio/speechPOST/v1/audio/speech:streamGET/v1/voices

Alternate model IDs

gemini-3.8-flash-lite-ttsgoogle/gemini-3.8-flash-lite-tts

Gemini 3.8 Flash-Lite TTS API pricing

Live pay-as-you-go rates from the EmpirioLabs catalog. You are billed only for what you use, with no monthly minimum.

How to call the Gemini 3.8 Flash-Lite TTS API

Gemini 3.8 Flash-Lite TTS serves speech through POST /v1/audio/speech and returns playable audio. Send the text to speak as input with the model id gemini-3-8-flash-lite-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-3-8-flash-lite-tts",
    "input": "Welcome to EmpirioLabs. Your build just finished."
  }' \
  --output speech.mp3

import requests

response = requests.post(
    "https://api.empiriolabs.ai/v1/audio/speech",
    headers={"Authorization": "Bearer YOUR_EMPIRIOLABS_API_KEY"},
    json={"model": "gemini-3-8-flash-lite-tts", "input": "Welcome to EmpirioLabs."},
)
with open("speech.mp3", "wb") as f:
    f.write(response.content)

Gemini 3.8 Flash-Lite TTS API parameters

Request parameters supported by the Gemini 3.8 Flash-Lite TTS API on EmpirioLabs. Defaults apply when a field is omitted.

Good to know

Limits

• Text: up to 5,000 characters per request
• Audio billing: 32 output tokens per second of generated audio
• 101 languages. The language of the text is detected automatically.

Voices

• The 30 voices in the voice list speak every supported language.
• GET /v1/voices?model=gemini-3-8-flash-lite-tts lists the full library of more than 2,000 voices across 30 locales, with the language, accent, gender, pitch, and a description of each. Filter it with language, gender, pitch, or q. Any id it returns works as voice or voice2; when you also set language, use the voice's own language.

Custom voices

• Set voice to custom and pass two recordings of the same adult speaker as https URLs: voice_audio_url, 10 to 30 seconds of natural speech, and voice_consent_audio_url, the speaker reading "I am the owner of this voice and I consent to Google using this voice to create a synthetic voice model." The statement is accepted in 30 languages; consent_statements on that parameter lists each wording.
• Record both in a quiet room on the same microphone. WAV, MP3, M4A, OGG, WEBM and FLAC are accepted, up to 15 MB each.
• The response includes voice_id and voice_id_expires_at. Pass the voice_id as voice or voice2 to reuse the voice for 7 days without new recordings. Anyone with the id can use the voice until it expires, so keep it private.

Delivery direction

• Put direction for the whole passage in style_prompt rather than in the text, for example "warm, unhurried, and reassuring".
• Place vocal tags inline where the sound should happen. Use these English tags even when the text is in another language:

<argh> <breath> <heavy breath> <exhales> <cackle> <cheer> <chuckle> <chuckles> <cough> <cry> <gasp> <giggle> <groan> <growl> <grunt> <grr> <hiss> <laugh> <laughter> <moan> <pant> <pff> <phew> <scream> <shout> <shriek> <sigh> <sighs> <sneeze> <snicker> <snort> <sob> <throat-clearing> <tsk> <whimper> <whispers> <whispering> <yawn> <short pause> <long pause>

• Capitalize a word to stress it. Wrap a listener reaction in pipes, for example |mm-hmm|, to add it without starting a new turn.

Multi-speaker

• Up to two speakers per request. Start each line with a speaker name and a colon, for example Speaker1: and Speaker2:. The names must match speaker1_name and speaker2_name.

Output

• WAV, MP3, OGG (Opus), ALAW, or MULAW, at 8,000 to 48,000 Hz.
• POST /v1/audio/speech:stream sends 16-bit PCM chunks at 24,000 Hz while the audio is generated, then the complete file in the requested format. speed is available on POST /v1/audio/speech only.

Gemini 3.8 Flash-Lite TTS API: common questions

How much does the Gemini 3.8 Flash-Lite TTS API cost?

On EmpirioLabs, Gemini 3.8 Flash-Lite TTS is billed pay as you go: Input $2.60 per 1M prompt tokens; Output $31.20 per 1M generated tokens. The live rate card on this page always matches what the API charges.

Which endpoint does Gemini 3.8 Flash-Lite TTS use?

Gemini 3.8 Flash-Lite TTS is served through POST /v1/audio/speech on api.empiriolabs.ai with standard bearer-token authentication.

Can I try Gemini 3.8 Flash-Lite TTS in the browser before integrating?

Yes. The EmpirioLabs playground runs Gemini 3.8 Flash-Lite TTS in the browser with the same parameters the API exposes, so you can test prompts before writing code.

How do I get a Gemini 3.8 Flash-Lite TTS API key?

Create an EmpirioLabs account, then generate a key under API Keys in the dashboard. Billing is pay-as-you-go credits, so you only pay for the requests you make.