SOLID Principles in Low-Level DesignInterview Readiness Check

Learning path

What this module tests

• Conceptual understanding of solid principles fundamentals
• Trade-offs and design decisions in real system scenarios
• SRP and OCP — applied knowledge
• Interview-style reasoning and explanation quality

Frequently asked questions

What does the SOLID Principles check test?

The check covers five design rules that prevent class rot — how each principle is violated in real codebases and the minimal refactor that fixes it. Questions span beginner to advanced difficulty and test both conceptual understanding and practical trade-off reasoning.

What keywords should I know for SOLID Principles?

Key concepts include: SRP, OCP, LSP, ISP, DIP, single responsibility, open closed, Liskov, interface segregation, dependency inversion, coupling, cohesion. These frequently appear in low-level design interviews at product and infrastructure companies.

How many questions are in the check?

Each check has 10 questions — a mix of MCQ and short-answer. You get scored by dimension (e.g., scalability, consistency) so you know exactly where to focus.

How long does it take to study SOLID Principles?

Most engineers spend around 4 hours on this module. The check itself takes about 10–15 minutes. You can retake it up to 3 times per day.

What prerequisite knowledge do I need before SOLID Principles?

SOLID Principles builds on OOP Design Principles. Complete those first for the best results.

Is SRP, OCP, LSP covered?

Yes. The SOLID Principles module covers SRP, OCP, LSP among other key concepts. The check includes questions that reflect real low-level design interview patterns.

What this unlocks