# Gemini 3.1 Flash TTS (preview)

Gemini 3.1 Flash TTS (preview) is a text-to-speech model from Google, available through the Impossibl API. The advertised input rate is $1.00 per million input tokens. The advertised output rate is $20.00 per million output tokens.

- Model identifier: ` google/gemini-3.1-flash-tts-preview `
- Creator: Google
- Model type: Text to speech
- Canonical model page: [Gemini 3.1 Flash TTS (preview)](<https://impossibl.com/google/gemini-3.1-flash-tts-preview>)
- API availability: Listed as serving through Impossibl.
- Creator release date: 2026-04-15

## Capabilities and limits

- Context window: Not published
- Maximum output tokens: Not published in the public catalog; this is separate from the context window.
- Inputs: text
- Outputs: audio
- Tool calling: Not published
- Voices: Zephyr, Puck, Charon, Kore, Fenrir, Leda, Orus, Aoede, Callirrhoe, Autonoe, Enceladus, Iapetus, Umbriel, Algieba, Despina, Erinome, Algenib, Rasalgethi, Laomedeia, Achernar, Alnilam, Schedar, Gacrux, Pulcherrima, Achird, Zubenelgenubi, Vindemiatrix, Sadachbia, Sadaltager, Sulafat

## API access

Use ` google/gemini-3.1-flash-tts-preview ` as the model identifier through the Impossibl API.

Published API endpoints:

- ` /v1/audio/speech `

[API quickstart](<https://impossibl.com/docs/agent-quickstart>) · [Models and billing documentation](<https://impossibl.com/docs/models>)

## Published API prices

All rates are in USD. An unpublished rate is unknown, not zero. Workspace-specific pricing, taxes, balance-purchase fees, billing adjustments, and tool charges can affect the amount paid.

| Usage | Published base rate | Billing unit |
| --- | --- | --- |
| Input | $1.00 | per million input tokens |
| Output | $20.00 | per million output tokens |
| Cache read | Not published | per million cached input tokens |
| Cache write (default retention) | Not published | per million tokens |
| Cache write (one-hour retention) | Not published | per million tokens |
| Audio input | Not published | per million audio input tokens |

## Availability and retirement

The model is listed as serving. No retirement is announced in the current public catalog.

## Frequently asked questions

### What is Gemini 3.1 Flash TTS (preview)?

Gemini 3.1 Flash TTS (preview) is a text-to-speech model from Google, available through the Impossibl API.

### How much does Gemini 3.1 Flash TTS (preview) cost?

Gemini 3.1 Flash TTS (preview) costs $1.00 per million input tokens and $20.00 per million output tokens through the Impossibl API. All rates are in USD.

### What inputs and outputs does Gemini 3.1 Flash TTS (preview) support?

Gemini 3.1 Flash TTS (preview) accepts text as input. Gemini 3.1 Flash TTS (preview) returns audio. Available voices include Zephyr, Puck, Charon, Kore, Fenrir, Leda, Orus, Aoede, Callirrhoe, Autonoe, Enceladus, Iapetus, Umbriel, Algieba, Despina, Erinome, Algenib, Rasalgethi, Laomedeia, Achernar, Alnilam, Schedar, Gacrux, Pulcherrima, Achird, Zubenelgenubi, Vindemiatrix, Sadachbia, Sadaltager, and Sulafat.

### How do I use Gemini 3.1 Flash TTS (preview) through an API?

Gemini 3.1 Flash TTS (preview) is available through the Impossibl API. Use google/gemini-3.1-flash-tts-preview as the model identifier with /v1/audio/speech. The quickstart explains how to create an API key and send your first request.

### When was Gemini 3.1 Flash TTS (preview) released?

Google released Gemini 3.1 Flash TTS (preview) on April 15, 2026.

Sources: [Creator release announcement](<https://ai.google.dev/gemini-api/docs/changelog>)

## Sources and related links

Prices, limits, capabilities, endpoints, and availability come from the public Impossibl catalog. Creator documentation supplies descriptions and release dates where available; it does not override the published API offering.

- [Public Impossibl model catalog](<https://api.impossibl.com/v1/models>)
- [Full model directory as JSON](<https://impossibl.com/models.json>)
- [Gemini 3.1 Flash TTS (preview): model details and pricing](<https://impossibl.com/google/gemini-3.1-flash-tts-preview>)
- [Model directory](<https://impossibl.com/models>)