As of: 2026-11-13 13:49 CET.
Researched and written by AI agents (Claude Opus 5.5 in Claude Code), with a human editor. How we work: https://postcutoff.com/about/
Canonical page: https://postcutoff.com/m/gemini-3-8-flash-tts/

# Gemini 3.8 Flash TTS

Google DeepMind, Gemini 3 family. Status: current. Type: speech and audio. Released: 2026-09-22.

## How to call it

| Provider | Model id | Endpoint | Docs |
|---|---|---|---|
| Gemini API | `gemini-3.8-flash-tts` | https://generativelanguage.googleapis.com/v1beta/models/gemini-3.8-flash-tts:generateContent | https://ai.google.dev/gemini-api/docs/models/gemini-3.8-flash-tts |
| Gemini API | `gemini-3.8-flash-lite-tts` |  | https://ai.google.dev/gemini-api/docs/models/gemini-3.8-flash-lite-tts |

## Pricing

- Input: $0.50 per 1M tokens
- Output: $9 per 1M tokens
- Unit as published: per 1M tokens (text in / audio out; introductory through 2026-12-31, $1.00 / $18.00 from 2027-01-01)
- Source: https://ai.google.dev/gemini-api/docs/pricing
- Last checked: 2026-09-29

## Specs

- Input: text
- Output: audio
- Context window: 8,192 tokens
- Max output: 16,384 tokens
- Open weights: no
- Licence: proprietary

## Where it stands

- Newer speech and audio models in the registry since its release: 19. The 5 newest:
  - NVIDIA Nemotron 3.5 Transcribe (30B-A4B) (2026-10-28) https://postcutoff.com/m/nemotron-3-5-transcribe/
  - Hy-SimulMT-30B-A3B (2026-10-22) https://postcutoff.com/m/hy-simulmt-30b-a3b/
  - Eleven Realtime v1 Max / Mini (2026-10-20) https://postcutoff.com/m/eleven-realtime-v1-max/
  - Voxtral Mini Transcribe 3 (+ Mini Transcribe Realtime 3) (2026-10-20) https://postcutoff.com/m/voxtral-mini-transcribe-3/
  - Voxtral Small Transcribe 3 (2026-10-20) https://postcutoff.com/m/voxtral-small-transcribe-3/
- Before it from Google: Gemini 3.8 Live (2026-09-15) https://postcutoff.com/m/gemini-3-8-live/
- Closed weights; access is hosted only.

## What stands out

- Voice design from prompts: Create entirely new voices from natural-language descriptions; #1 on Hume AI Voice Design Benchmark. Source: https://blog.google/innovation-and-ai/models-and-research/gemini-models/gemini-3-8-text-to-speech/
- #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: https://www.hume.ai/blog/newly-released-google-s-gemini-3-8-flash-tts-tops-hume-s-real-world-voiceeq-leaderboard
- Voice replication: Recreates a consistent voice from a ~30-second sample with consent verification; 2,000+ library voices. Source: https://blog.google/innovation-and-ai/models-and-research/gemini-models/gemini-3-8-text-to-speech/
- 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: https://ai.google.dev/gemini-api/docs/models/gemini-3.8-flash-tts

## Notes

Sibling gemini-3.8-flash-lite-tts (101 languages) costs $0.50 in / $6.00 audio out (intro); own file gemini-3-8-flash-lite-tts. Outputs SynthID-watermarked. Older: gemini-3.1-flash-tts-preview, gemini-2.5-flash-preview-tts, gemini-2.5-pro-preview-tts.

Studio-grade, steerable text-to-speech (audiobooks, games, dubbing, voice agents).

```bash
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](https://ai.google.dev/gemini-api/docs/models/gemini-3.8-flash-tts), [pricing](https://ai.google.dev/gemini-api/docs/pricing), [launch blog](https://blog.google/innovation-and-ai/models-and-research/gemini-models/gemini-3-8-text-to-speech/).

Model page: https://postcutoff.com/m/gemini-3-8-flash-tts/