Gemini 3.1 Flash TTS Preview vs Grok Voice TTS 1.0: side-by-side summary

Gemini 3.1 Flash TTS Preview and Grok Voice TTS 1.0 are available through the OpenRouter API, so switching between them takes a model slug change rather than a new integration.

Gemini 3.1 Flash TTS Preview, from Google, has a 32,768-token context window and is priced at $1/M tokens input, $20/M tokens output on OpenRouter.

Grok Voice TTS 1.0, from SpaceXAI, has a 15,000-token context window and is priced at $15/M characters on OpenRouter.

Context window

• Gemini 3.1 Flash TTS Preview: 32,768 tokens
• Grok Voice TTS 1.0: 15,000 tokens

Price

• Gemini 3.1 Flash TTS Preview: $1/M tokens input, $20/M tokens output
• Grok Voice TTS 1.0: $15/M characters

Provided by

• Gemini 3.1 Flash TTS Preview: Google
• Grok Voice TTS 1.0: SpaceXAI

• Gemini 3.1 Flash TTS Preview model details, providers and pricing
• Grok Voice TTS 1.0 model details, providers and pricing