Product demo
See the proof loop before you pay.
This is the public version of the quantlab workflow: skill diagnosis, adaptive study plan, interview exercise, and grading evidence in one loop.
Guided loop
Readiness proof
Paid decision
Pro recommendations appear after evidence, not before it.
Skill radar
Find the weak spots interviewers will press on.
quantlab turns lesson history, graded answers, hints, and review misses into a readable skill map.
Java concurrency
Strong
PostgreSQL plans
Fragile
Architecture trade-offs
Progressing
Auth and sessions
Needs proof
Current signal
4 fragile signals found
Each step leaves evidence that updates the map, FSRS queue, and next exercise.
Free proves fit
Public topics, lesson previews, skills map, and this demo stay open so visitors can judge the method.
Pro proves readiness
Private telemetry, AI grading, adaptive missions, and synced proof history become the paid product.
Commercial boundary
The demo sells the loop, not magic.
Free shows the method. Pro charges for private telemetry, AI grading, adaptive missions, and synced proof history. That boundary keeps monetization ready for Stripe and MercadoPago without hiding what each user gets.
Next intent
- Free: Public topics, lesson previews, skills map, and this demo stay open so visitors can judge the method.
- Pro: Private telemetry, AI grading, adaptive missions, and synced proof history become the paid product.