Solve
The e-book viewer that grades.
Korea's only auto-grading viewer built for test-prep books.
Why is test prep still stuck on paper?
Tablet penetration in Korea has reached 70% — the hardware is already in students' hands. Yet test-prep books, which make up 70% of the Korean book market, remain a blind spot of digital transformation. Even the major online bookstores offer no e-book option for them.
EPUB and generic PDFs can't preserve the complex layouts of test-prep books, and features like handwriting, grading, and linked explanations simply don't exist. So students buy the paper book, cut off the spine, scan every page, and import it into a note-taking app.
The demand is clear. The format was the problem.
Our approach
We start from the PDFs publishers already have. Without altering the original, we locate every question and answer at the pixel level, then layer handwriting, grading, and explanations on top.
Our proprietary multi-layer architecture runs the content, interaction, and handwriting layers independently — fully protecting the publisher's copyright while delivering an interactive study experience.
Multi-layer
Three core technologies
Multi-layer architecture
A proprietary architecture that runs content, interaction, and handwriting as independent layers. The publisher's source PDF is preserved 100% as-is — a non-destructive approach that fully protects copyright.
Automated conversion
AI detects the position of every question and answer in a PDF at the pixel level. Publishers turn existing PDF assets into gradable content right away — no extra conversion or editing work.
Precision ink engine
Our in-house engine delivers ultra-low-latency handwriting under 20 ms. Every solution is captured stroke by stroke, forming the foundation for personalized learning analytics.
Turning test-prep books into high-margin digital products.