Gemma 3 27B and Gemma 3 4B are available through the OpenRouter API, so switching between them takes a model slug change rather than a new integration.
Gemma 3 27B, from Google, has a 131,072-token context window and is priced at $0.08/M tokens input, $0.16/M tokens output on OpenRouter.
Gemma 3 4B, from Google, has a 131,072-token context window and is priced at $0.05/M tokens input, $0.10/M tokens output on OpenRouter.