Codelet vs SD Primer

∙ Identify and analyze the core patterns and approaches ∙ View how well you’re doing and where you can improve ∙ Practice coding questions anywhere and anytime

Think like a staff engineer — five minutes a day. SD Primer turns system design mastery into a daily habit. Answer today's questions, debug a broken architecture with your hands, and build the instincts that tech interviews (and real jobs) demand. YOUR DAILY RITUAL • Daily Quiz — five sharp multiple-choice questions on scalability, databases, caching, queues, and trade-offs, with clear explanations for every answer • Focus Practice — we detect your weakest topics and serve extra reps exactly where you need them • Streaks, XP, and levels that make consistency effortless HANDS-ON ARCHITECTURE LABS Don't just read about system design — fix it. Each lab drops you into a live incident: drag components onto the canvas, wire the fix, defend your reasoning, and get scored with strengths and trade-offs. LEARN AI & ML FROM FIRST PRINCIPLES A structured 64-lesson course, one daily read at a time: from the origins of AI through neural networks, transformers, and how to actually use LLMs well — written for software engineers, no math degree required. AND EVERY DAY • Coding pattern drills — name the algorithm behind the problem • Workplace mastery lessons — the soft skills that get engineers promoted • Curated engineering news and daily tips • Your progress, visualized: topic strength, consistency calendar, achievements SD PRIMER PRO Unlock custom quizzes, labs, and pattern sessions tuned to your goals, plus higher daily limits. Subscriptions auto-renew unless cancelled at least 24 hours before the end of the period; manage anytime in your App Store account settings. Privacy Policy: https://sdprimer.com/privacy Terms of Use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/ Start today. Your future self at the whiteboard will thank you.