Nano Banana 2 (Gemini 3.1 Flash Image) and Mistral Small 4 are available through the OpenRouter API, so switching between them takes a model slug change rather than a new integration.
Nano Banana 2 (Gemini 3.1 Flash Image), from Google, has a 131,072-token context window and is priced at $0.50/M tokens input, $3/M tokens output on OpenRouter.
Mistral Small 4, from Mistral AI, has a 262,144-token context window and is priced at $0.15/M tokens input, $0.60/M tokens output on OpenRouter.