BlueDot42.

A one-person edtech business in South Korea. We make low-cost exam practice for students who study without private tutoring. Our products are built and maintained with Claude Code.

Why we exist

South Korean households spent KRW 29.2 trillion on private education for primary and secondary students in 2024 (Statistics Korea). Students who don't attend an academy usually prepare for school exams with generic workbooks. We want to give them two things a good tutor gives: practice organised around what their school exams cover, and feedback on why an answer was wrong.

Products

BlueDot Exam — school exam practice (live since September 2026)

• Practice for Korean middle-school exams, organised around the topics that appear in past school exams. We write new questions; past exam text is not republished.
• About 1,400 published questions in math, Korean, social studies and science for grade 7 (second semester). More grades are in progress.
• Answer check. One model writes a question and its answer. A second model solves the question without seeing the answer, and disagreements are filtered out. In our first runs about 7% of generated questions failed this check. Agreement is one quality check, not a guarantee.
• Geometry diagrams are drawn from coordinates in code, then compared with the question text.
• After a wrong answer, the student marks it as a calculation slip or a missing idea. A missing idea leads to easier, similar questions. Missed questions come back after 1, 3 and 7 days.
• The core practice flow does not ask for a name or school. Practice progress is stored on the student's device.
• Prototype (not public yet): generating new practice questions from a photo of a workbook page.

When You Miss Earth — 3D globe learning app

An interactive 3D globe for exploring Earth science and history, on Google Play.

YouTube

Explainer videos in English (@bluedot42) and Korean (@블루닷42).

How we build with Claude

• Claude Code is our main development tool. We use it to write and maintain the web app, the Android app, this website and the question pipeline.
• In that workflow Claude Code also coordinates other tools: it splits large jobs, hands bulk generation and cross-checks to sub-agents and other models, and reviews their output. The founder decides what ships.
• Question generation in production currently runs on another provider's models. We plan to test the Claude API for generation, answer checks and explanations.

What's next

• Test Claude for question generation and independent answer checks.
• Explanations that respond to the student's specific wrong answer, not just the correct solution.
• Grades 8 to 10, a parent report, and a paid plan for school-matched practice. Basic practice stays free.

Company

Timeline