# SD Primer — System Design Primer

> System Design Primer (iPhone/iPad app by Ernesto Hilvano.)

- Source: https://appshunter.io/ios/app/sd-primer/id6758010557 (this page in markdown: same URL + `.md`)
- Developer: [Ernesto Hilvano](https://appshunter.io/developer/1740292069)
- Category: Education
- Price: Free with in-app purchases
- Age rating: 4+
- Requires: iOS 17.0 · 20 MB
- Languages: American English
- Released: 2026-01-21
- Data updated: 2026-08-04
- User reviews in markdown: https://appshunter.io/ios/app/sd-primer/id6758010557/reviews.md

## What is SD Primer?

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.

## Pricing and in-app purchases

Base price: Free.

**Subscriptions**

| Subscription | Price | Period |
| --- | --- | --- |
| SDPrimer Pro | $9.99 | per month |
| SDPrimer Pro | $99.99 | per year |



## Version history (last 5 releases)

### 2.0.1 — 2026-07-19

Making it faaaaast

### 2.0.0 — 2026-07-18

SD Primer 2.0 is a complete rebuild — 100% native, dramatically faster, and wearing a brand-new dark design.

• NEW: AI/ML Foundations — a 64-lesson course from the history of AI to using LLMs well
• NEW: Focus Practice targets your weakest topics automatically
• NEW: Redesigned hands-on architecture labs with a zoomable canvas
• Faster everywhere: instant app open, snappier answers, smoother animations
• Full iPad support
• Streak freezes protect your progress when life happens

Note: this update signs you out once — sign back in with Google or Apple and everything is right where you left it.

### 1.0.3 — 2026-03-26

- Coding pattern recognition
- System design lab
- Improve home (added news, did you know, daily workplace mastery)
- added new resource for coding interview and takehome project.
- added support for feature requests
- paywall for user who wants customized learning

### 1.0.2 — 2026-01-28

- Improved UI, added animation, interaction
- screenshot improvements

### 1.0.1 — 2026-01-26

Improved Quality of questions and daily concepts

## More apps by Ernesto Hilvano

- [TayoFit](https://appshunter.io/ios/app/tayofit/id6483860375)

All apps by Ernesto Hilvano: https://appshunter.io/developer/1740292069

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-08-04.*