Clarify behavior
Identify actors, use cases, constraints, invariants, and realistic extension points.
26 live OOD interviews
Practice OOD as a real coding interview
Turn ambiguous behavior into clear responsibilities, interfaces, and working collaborations while a live interviewer probes your choices and adapts the requirements.
Interview flow
Make the design executable and explainable
Model responsibilities
Choose cohesive objects, ownership boundaries, relationships, and lifecycles.
Implement the collaboration
Work across files in an IDE-style editor while explaining APIs and trade-offs.
Validate and evolve
Walk through scenarios, edge cases, test seams, and a live change request.
Multi-file workspace
Work across classes, interfaces, and tests
Create, rename, delete, and switch files in an IDE-style editor while you build and explain the central collaboration.
Evidence-based report
Review the reasoning and final workspace
Feedback evaluates requirements, responsibility design, implementation quality, trade-offs, validation, and the independence of your decisions.
Common OOD interview questions
Know what this format is testing
How is OOD different from System Design?
OOD focuses on object responsibilities, interfaces, collaborations, invariants, and changeability inside an application. System Design focuses more heavily on distributed components, scale, data flow, and reliability.
Do I need to write code?
Yes. You model the design and implement its key collaboration in a multi-file workspace. The goal is not volume; it is executable evidence that the responsibilities and APIs fit together.
What feedback do I receive?
The report covers requirement clarity, modeling, API design, extensibility, implementation quality, validation, trade-offs, and how independently you defended the final design.