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, a vibe check (safe to use? friends only? careful?) and a story — and when the origin is uncertain, it says so instead of inventing one. Built end to end with AI agents in Claude Code. 13 languages, works offline. No streaks, no tests, no XP.
Hi Product Hunt! Solo developer from Japan here.
I kept meeting people who had studied Japanese for years and still couldn't follow a group chat. The vocabulary that actually carries everyday conversation — slang, internet speak, fandom words — is exactly what textbooks leave out.
But I didn't want to build another study app. No streaks, no tests, nothing that guilt-trips you for missing a day. YABAI is built like a snack: giant Japanese typography, one word per card, swipe to discover, save the ones you love.
The part I spent the most time on is honesty. Every word is researched and written in Japanese first, then translated into 13 languages — not machine-translated out of English. And where a word's origin is genuinely disputed (yabai itself is a good example), the app says "nobody agrees" instead of picking a tidy story. Invented etymology is everywhere in slang content and I didn't want to add to it.
308 words so far, and it all works offline.
I'd love feedback — especially from Japanese learners: which words surprised you, and what's missing?
hi, it's an interesting project, really nice idea.
before installing it, i'd like to understand: is it free or is it a paid app?
308 words is a pretty specific number, curious how you picked the cutoff there. is that meant to be a complete "you can follow along with native content now" set, or is it deliberately a starter pack with more packs planned later
About YABAI on Product Hunt
“Real Japanese slang, one giant word at a time”
YABAI launched on Product Hunt on September 20th, 2026 and earned 91 upvotes and 13 comments, placing #11 on the daily leaderboard. 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, a vibe check (safe to use? friends only? careful?) and a story — and when the origin is uncertain, it says so instead of inventing one. Built end to end with AI agents in Claude Code. 13 languages, works offline. No streaks, no tests, no XP.
YABAI was featured in Android (57.6k followers), Education (79.2k followers) and Languages (14.5k followers) on Product Hunt. Together, these topics include over 87.2k products, making this a competitive space to launch in.
Who hunted YABAI?
YABAI was hunted by Yuichi Sato. A “hunter” on Product Hunt is the community member who submits a product to the platform — uploading the images, the link, and tagging the makers behind it. Hunters typically write the first comment explaining why a product is worth attention, and their followers are notified the moment they post. Around 79% of featured launches on Product Hunt are self-hunted by their makers, but a well-known hunter still acts as a signal of quality to the rest of the community. See the full all-time top hunters leaderboard to discover who is shaping the Product Hunt ecosystem.
Want to see how YABAI stacked up against nearby launches in real time? Check out the live launch dashboard for upvote speed charts, proximity comparisons, and more analytics.
Yuichi Sato