Textbooks teach Japanese that stops at the classroom door. YABAI is the other half: 308 real slang, internet, and fandom words, each on a card built around giant Japanese typography. Every word has a meaning, a real example, and a vibe check that tells you if it is safe to use, friends only, or needs care. Each card also includes a story, and when the origin is uncertain, YABAI says so instead of inventing one. Built end to end with AI agents in Claude Code. Supports 13 languages, works offline, and has no streaks, no tests, and no XP.
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