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Updated weekly · Last refresh Sep 13

Top 50 design patterns Interview Questions

The most frequently asked design patterns questions across all roles and companies, ranked by real interview frequency. Updated daily.

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1
CodingStart here. 25 questions · ~246 min
Design Parking Lot ClassesMedium
Practice
Recently asked

Design an OOP parking lot system in Python using classes, abstraction, and efficient spot tracking.

abstractiondesign patternsoopPlaylistPhonepe
Debounce or Throttle UtilityMedium
Practice

Simulate trailing-edge debouncing for Dream11 search events using timestamps and a pending event.

debouncingdesign patternsDDream11Intercontinental Exchange Holdings
Singleton Pattern ImplementationMedium
Practice

Implement a Singleton class that preserves one instance, initializes state once, and remains safe under concurrent construction.

clean codeabstractionProgrammingEEcolabAmerican Express
Refactoring in an OOP AppHard
Practice

Build an extensible OOP text pipeline whose normalization, tokenization, and frequency stages compose cleanly.

application developmentclean codeabstractionAnthropic
Thread-Safe Singleton PatternMedium
Recently asked

Explain how to implement a singleton safely under concurrency and avoid race conditions during initialization.

thread safetydesign patternspythonHERE TechnologiesMotorolaCCadence Design Systems
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2
Behavioral & Leadership5 questions · ~49 min
Leading Through Vague Product RequirementsEasy
Recently asked

Tests ownership and prioritization when mobile requirements are ambiguous and the candidate must align stakeholders to ship.

builder patterndesign patternstechnical explanationNexHealthStealth StartupKabbage
Leading a Mobile Architecture ResetMedium

Tests leading through ambiguity in mobile architecture decisions, with ownership, influence without authority, and prioritization under delivery pressure.

mobile applicationdesign patternsstate managementCspringCapgemini FSSBUArthrex
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3
Execution5 questions · ~49 min
Pattern Reuse vs Custom DesignMedium

Explain how you choose between reusing an existing design pattern and creating a custom UX solution.

Decision Makingcustom solutionsdesign patternsCapital OneDiversified Services NetworkComcast
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4
System Design10 questions · ~98 min
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5
More topics5 questions · ~49 min
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Hands-on SQL practiceWrite and run real queries in the editor. 3 drills · ~30 min
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