PrepPal: System Design Drills
5-Min Drills for Engineers
Free · In‑App Purchases · Designed for iPad
Don’t become an AI wrapper. Own the decisions.
PrepPal trains architectural intuition in 5 minutes a day through real engineering scenarios.
The daily mental gym for backend engineers fighting AI skill atrophy.
Master system design, architectural trade-offs, and API decisions in 5-minute mobile drills. Build muscle memory for interviews and real-world engineering.
PrepPal rebuilds your decision-making muscle through spaced repetition on architectural trade-offs.
No hour-long courses. No passive videos. Just 5-minute drills on the decisions that separate mid-level engineers from Staff:
- Cache at CDN vs app layer? Why?
- Eventual consistency vs strong consistency? Trade-offs?
- Microservices vs monolith for 5-person team? What breaks?
- API response time 800ms - sync or async? Justify.
3 Phases (Duolingo-style progression):
→ Phase 1 (Free): Fundamentals - Caching, databases, load balancing
→ Phase 2 (Free): Internals - Redis, Postgres, message queues
→ Phase 3 (PRO): Architecture - CAP theorem, distributed systems, consensus
Each drill: 30 seconds to decide. Spaced repetition brings back weak areas. Unlock advanced modules as you build competence.These are real interview questions. Real production decisions. Real career leverage.
27 modules. 533 micro-skills. 5 min/day.
Backend Focus:
- Caching (CDN, app, database layers)
- Databases (SQL vs NoSQL, indexing, sharding)
- APIs (REST, GraphQL, gRPC trade-offs)
- Message Queues (when to use, failure modes)
- Distributed Systems (consensus, replication)
- Microservices (when NOT to use)
- Scalability (vertical vs horizontal)
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Third party authentication fix
The developer, Sharon Mishayev, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
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The following data may be collected but it is not linked to your identity:
- User Content
- Usage Data
- Diagnostics
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Information
- Seller
- Sharon Mishayev
- Size
- 64.1 MB
- Category
- Education
- Compatibility
Requires iOS 13.0 or later.
- iPhone
Requires iOS 13.0 or later. - iPad
Requires iPadOS 13.0 or later. - iPod touch
Requires iOS 13.0 or later. - Mac
Requires macOS 11.0 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 1.0 or later.
- Languages
- English
- Age Rating
4+
- 4+
- In-App Purchases
Yes
- PrepPal PRO Yearly Plan $136.99
- PrepPal PRO Monthly Plan $19.99
- Copyright
- © PrepPal LTD 2024