Hi (midevil)John! Chatting and playtime in AI2U are fueled by in-game tokens, including the 10,000 tokens that accompany your first purchase of the game ๐๐ช While AI2U doesn't have options for external API keys, its predecessor and demo—Yandere AI Girlfriend Simulator—is free to download and allows players to plug in their own OpenAI API keys to play. Hope that helps!