SD Primer vs InterHub

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.

Build the technical fluency to walk into your next interview prepared. InterHub turns interview prep into a structured, adaptive practice routine, built specifically for software engineers targeting junior, mid, and senior roles. Pick your career path - backend, frontend, fullstack, mobile, DevOps, or AI, choose the technologies you actually use, set a target seniority, and InterHub generates a learning plan that adapts to your answers. Every session you complete sharpens the next one. WHY ENGINEERS USE INTERHUB: Adaptive Question Sessions Questions are selected based on your career path, chosen stack, and how you've answered previously. The system tracks weak topics and reinforces them - no padding, no filler, no cramming a curriculum that doesn't match your goal. Realistic Mock Interviews Run full mock interviews end-to-end. Answer by typing or by speaking, voice answers are transcribed and scored just like a real interviewer would assess your reasoning. Each interview ends with an overall verdict, per-question scores, and structured feedback you can act on. Progress Tracking That Reflects Reality Track your level per technology and across the radar of skills your target role requires. Snapshots over time show whether you're actually closing the gap to the seniority you're aiming for, or only practicing what you already know. Practice Mode for Daily Reps Short, focused sessions for the days you have ten minutes between meetings. Local on-device speech recognition means you can practice out loud without anything leaving your phone unless you opt in to cloud transcription for higher accuracy. WHAT'S INCLUDED: Career paths for backend, frontend, fullstack, mobile, DevOps, and AI/ML roles Question banks across the most common stacks (React, Django, Python, Node, TypeScript, and more) Junior, mid, and senior difficulty calibration Mock interviews with scoring and written feedback Voice or text answers, with on-device transcription by default Progress snapshots and per-technology level tracking Daily practice reminders at a time you choose INTERHUB PREMIUM: Premium unlocks unlimited mock interviews, the full question library across all paths, voice answer grading, and the complete progress dashboard. Available as a monthly or annual subscription. New users get a 7-day free trial. Payments and renewal: Payment is charged to your Apple ID at confirmation of purchase. Subscriptions automatically renew unless auto-renew is turned off at least 24 hours before the end of the current period. Your account is charged for renewal within 24 hours prior to the end of the current period. You can manage or turn off auto-renew in your Apple ID account settings at any time after purchase. No cancellation of the current subscription is permitted during an active billing period. PRIVACY: InterHub does not include any analytics or advertising SDKs. We do not collect IP addresses, location, contacts, or photos. Voice answers are transcribed locally on your device by default; cloud transcription is opt-in. See our privacy policy for the full list of sub-processors and data flows. Terms and conditions: https://interhub.tech/legal/terms-and-conditions Privacy policy: https://interhub.tech/legal/privacy-policy