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Table of contents
What is OOD/LLD Round?
How to Prepare for the OLD/LLD Round?
How to Clear the OOD/LLD Round?
Frequently Asked Questions
What is system design, and why is it important?
What are the key principles of system design?
What are the different stages of the system design process?
Last Updated: Mar 27, 2024

Unlocking the Secrets of the OOD/LLD Interview Round

Author Suraj Pandey
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What is OOD/LLD Round?

OOD/LLD Round is a technical interview that evaluates a candidate's knowledge and understanding of software design and architecture. It is typically part of the interview process for Software Engineering positions and aims to assess the candidate's ability to design and implement complex software systems.

what is ood/lld round

The OOD (Object Oriented Design) round of a software engineering interview assesses a candidate's comprehension of OOD concepts, principles, and practices. This evaluation encompasses the candidate's understanding of design patterns, SOLID principles, and UML (Unified Modeling Language). The interviewer will assess the candidate's practical experience in designing and executing software systems and ability to effectively communicate their design decisions and thought processes.

On the other hand, the LLD (Low-Level Design) round focuses on evaluating the candidate's capacity to decompose complex problems into smaller, more manageable components and implement these components in code. The interviewer will inquire about the candidate's experience working with data structures, algorithms, and coding practices. They will also assess the candidate's knowledge of techniques to optimize performance, handle errors, and debug software.

During an OOD/LLD (Object Oriented Design/Low-Level Design) round, the interviewer evaluates the candidate's software design and architecture knowledge and skills. This can involve questioning the candidate about specific design patterns and their experience in creating systems from scratch. The interviewer may also request the candidate to demonstrate their understanding and implementation of key concepts and principles by writing code on a whiteboard or computer.

How to Prepare for the OLD/LLD Round?

Preparation is key to success in any interview, especially regarding the technical aspects of software engineering. 

how to prepare for ood/lld round?

Here are some tips to help you prepare for an OOD/LLD round:

  1. Brush up on your design patterns: Design patterns are reusable solutions to common design problems. Familiarize yourself with the most commonly used design patterns, such as the Singleton, Factory, and Observer patterns.
  2. Study SOLID principles: SOLID is a set of design principles for writing maintainable and scalable software. Understanding the SOLID principles, such as Single Responsibility, Open/Closed, Liskov Substitution, Interface Segregation, and Dependency Inversion, will show your interviewer that you have a strong foundation in software design.
  3. Get familiar with UML: UML is a visual language that describes and visualizes software systems. Brush up on your UML skills, and be prepared to use it to explain your design decisions and thought process.
  4. Practice coding: Practicing your coding skills is essential, especially when it comes to implementing design patterns and solving algorithmic problems. Work on small projects that involve designing and implementing systems.
  5. Read books and articles: Read books and articles on software design and architecture to stay updated on the latest trends and practices in the field. Some recommended books include "Design Patterns: Elements of Reusable Object-Oriented Software" by the Gang of Four and "Clean Architecture" by Robert Martin.
  6. Join online forums and discussion groups: Participating in online forums and discussion groups related to software design and architecture will help you stay updated on the latest trends and best practices. It will also allow you to interact with other software engineers and ask questions.
  7. Practice coding under pressure: Writing code under pressure is an essential skill in software engineering. Practice writing code on a whiteboard or a computer during timed exercises to get used to the pressure of the interview setting.
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How to Clear the OOD/LLD Round?

Clearing the OOD/LLD round requires a combination of technical knowledge, practical experience, and strong communication skills. 

How to clear ood/lld round?

Here are some tips to help you clear this important stage of the interview process:

  1. Be confident: Confidence is critical when it comes to technical interviews. Believe in your skills and knowledge, and be prepared to demonstrate them in the interview.
  2. Listen carefully to the interviewer's questions: Ensure you understand the question before answering. If you're unsure, ask for clarification.
  3. Communicate your thought process: The interviewer wants to see how you approach a problem and your design decisions. Explain your thought process as you work through the problem, and make sure to mention the design patterns, SOLID principles, and UML diagrams you're using.
  4. Write clean and maintainable code: Make sure your code is readable and maintainable. Use comments and clear variable names to make your code easier to understand.
  5. Be open to feedback: Be open to feedback from the interviewer. If they suggest a different approach, be willing to consider it and incorporate it into your solution.
  6. Stay calm under pressure: Technical interviews can be stressful, but staying calm and focused is essential. Take deep breaths, and remember that mistakes happen. If you need help, feel free to ask for help.
  7. Show your passion for Software Engineering: The interviewer wants to see your passion for software engineering. Talk about your experiences, projects, and why you're interested in the field.

Frequently Asked Questions

What is system design, and why is it important?

System design defines the architecture, components, modules, interfaces, and data for a system to meet specified requirements. It is essential because it ensures the system is efficient, reliable, and scalable.

What are the key principles of system design?

The key principles of system design are modularity, abstraction, encapsulation, coupling, cohesion, and separation of concerns.

What are the different stages of the system design process?

The different stages of the system design process are requirements analysis, system architecture design, module design, database design, and user interface design.


The OOD/LLD round in a software engineering interview is a crucial evaluation of a candidate's abilities in software design and architecture. This round allows the interviewer to assess the candidate's understanding and implementation of complex systems by demonstrating theoretical knowledge, practical experience, and effective communication skills.

To prepare for this round, candidates should focus on refining their knowledge of design patterns, SOLID principles, UML, coding, and staying current with industry trends. By doing so, they increase their chances of success during the interview.

During the OOD/LLD round, it is essential for candidates to exhibit confidence, listen attentively to the interviewer's questions, clearly articulate their thought process, write clean and maintainable code, be receptive to feedback, maintain composure under pressure, and showcase their passion for software engineering.

Now that you have acquired a comprehensive understanding of OLD/LDD and have learned the techniques for preparing for these assessments, you are well-equipped to tackle various system design-related challenges posed by product-based companies.

We encourage you to continue advancing your skills and expanding your knowledge in the field of system design. Our System Design guided path serves as a valuable resource in furthering your education and development.

We are confident that the information provided in this blog post has been of assistance to you. Your feedback is greatly appreciated and we would appreciate it if you shared your thoughts in the comments section. Your input will aid our efforts to improve continually and provide high-quality content for our readers.

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