I built an AI correction tool for Korean writing practice — here's what I learned

Korean learners have plenty of vocabulary apps and grammar quizzes, but almost nothing helps them with the most important skill: actually writing in Korean and getting real feedback.

So I built Korean Diary AI — you write a diary entry in Korean, and the AI gives you natural, human-like corrections with explanations. No gamification, no drills. Just writing and learning.

**What I launched with:**

- Free tier (3 corrections/month)

- Pro plan ($9/mo, unlimited corrections)

- Google OAuth + email signup

- Launched on Product Hunt on March 28

**Biggest lesson so far:** Getting your first users outside your existing network is brutally hard. Working on that now.

Would love feedback from anyone who's built language-learning tools or solo-launched a SaaS. Happy to answer questions.

→ https://www.kdiaryai.com