Gemini 3.8 Flash TTS
Sibling gemini-3.8-flash-lite-tts (101 languages) costs $0.50 in / $6.00 audio out (intro). Outputs SynthID-watermarked. Older: gemini-3.1-flash-tts-preview, gemini-2.5-flash-preview-tts, gemini-2.5-pro-preview-tts.
- Context window
- 8,192 tokens
- Max output
- 16,384 tokens
- Input
- text
- Output
- audio
- License
- proprietary
- Pricing
- input: $0.5 · output: $9 (per 1M tokens (text in / audio out; introductory through 2026-12-31, $1.00 / $18.00 from 2027-01-01)) source
- Verified
- 2026-09-29
How to call it
| Provider | Model id | Endpoint / URL | Docs |
|---|---|---|---|
| Gemini API | gemini-3.8-flash-tts | https://generativelanguage.googleapis.com/v1beta/models/gemini-3.8-flash-tts:generateContent | docs |
| Gemini API | gemini-3.8-flash-lite-tts | — | docs |
Notable capabilities (4)
- Voice design from prompts: Create entirely new voices from natural-language descriptions; #1 on Hume AI Voice Design Benchmark. source
- #1 on Hume Real-World VoiceEQ leaderboard (found after launch): Hume's blind human-rated benchmark (2026-09-24): Gemini 3.8 Flash TTS 0.920 and Flash-Lite TTS 0.914 expressivity-reliability score, ahead of Gemini 2.5 Pro TTS (0.880) and Cartesia Sonic 3.6 (0.840); long-form stability up from 1.22 to ~2.9-3.0/5, but weaker speaker similarity (3.68/5). source
- Voice replication: Recreates a consistent voice from a ~30-second sample with consent verification; 2,000+ library voices. source
- Directed long-form multi-speaker audio: Line-by-line direction of pacing/emotion, dual-speaker staging, stable over hours; 130+ languages with auto-detection. source
Studio-grade, steerable text-to-speech (audiobooks, games, dubbing, voice agents).
curl "https://generativelanguage.googleapis.com/v1beta/models/gemini-3.8-flash-tts:generateContent" \
-H "x-goog-api-key: $GEMINI_API_KEY" -H "Content-Type: application/json" \
-d '{"contents":[{"parts":[{"text":"Say cheerfully: Have a wonderful day!"}]}],
"generationConfig":{"responseModalities":["AUDIO"]}}'
Sources: model page, pricing, launch blog.
Other Google DeepMind models
Gemini 3.8 Live · Gemini 3.8 Flash · Gemini 3.5 Transcribe (and Transcribe Live) · Lyria 3.5 · Gemini 3.5 Flash-Lite · Nano Banana 2 Lite (Gemini 3.1 Flash-Lite Image) · Gemini Omni Flash (Omni 1.1 Flash) · Gemini Embedding 2 · Gemma 4 · Nano Banana 2 (Gemini 3.1 Flash Image) · Nano Banana Pro (Gemini 3 Pro Image) · Gemini Robotics 2 · Gemini Robotics ER 2 · Gemini Robotics On-Device 2 · Gemini 3.5 Live Translate · Gemini 3.1 Pro · Veo 3.1 · Genie 3 · Lyria RealTime · Gemini 3.7 Flash · Gemini 3.6 Flash · Gemini 3.5 Flash · Gemini 3.1 Flash TTS (preview) · Gemini 3.1 Flash Live (preview) · Lyria 3 (Clip / Pro) · Lyria 2 · Gemini 2.5 Flash Native Audio (Live, preview) · Gemini 2.5 Flash-Lite · Gemini 2.5 Flash · Gemini 2.5 Pro · Gemini 2.5 Flash TTS / Pro TTS · Gemini 3.1 Flash-Lite · Nano Banana (Gemini 2.5 Flash Image) · Gemini Robotics-ER 1.5 / 1.6 · Imagen 4