S2 Pro vs Gemini 3.1 Flash TTS Preview: side-by-side summary

S2 Pro and Gemini 3.1 Flash TTS Preview are available through the OpenRouter API, so switching between them takes a model slug change rather than a new integration.

S2 Pro, from fish-audio, is priced at $15/M UTF-8 bytes on OpenRouter.

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.

Context window

• S2 Pro: Not published
• Gemini 3.1 Flash TTS Preview: 32,768 tokens

Price

• S2 Pro: $15/M UTF-8 bytes
• Gemini 3.1 Flash TTS Preview: $1/M tokens input, $20/M tokens output

Provided by

• S2 Pro: fish-audio
• Gemini 3.1 Flash TTS Preview: Google

• S2 Pro model details, providers and pricing
• Gemini 3.1 Flash TTS Preview model details, providers and pricing