Interview Preparation Guide​
Backend Engineer (Node.js)
Table of Contents
Introduction​
Reminder of our process​
What We Look For​
Technical Proficiency​
Behavioral Skills​
Preparing for the process​
Home Assignment Preparation​
Key areas to focus on​
Additional Tips​
Technical Interview Preparation​
Master the Fundamentals​
Strengthen Your Architecture Skills​
Security is Paramount​
Embrace Teamwork and Communication​
Testing is Key​
Embrace Agile Development​
Additional Tips​
Final Stage​
Ask Questions!​
Introduction
This guide is here to help you get ready for your Backend Engineer interview at Deel. ​
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We view this interview as a two-way opportunity: it’s a chance for us to learn about your skills
and experiences, and for you to get to know more about Deel.​
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We're looking for talented individuals with strong technical skills, especially in Node.js and
databases. Equally important, we want people who will not only fit in but also add to our team
culture, as we aim to facilitate remote work globally. ​
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Reminder of our process
As explained over the first call, next steps will include:
●​ Home Task Assignment: You will receive instructions for the assignment to be completed
prior to the technical interview. If successful, we move to the next stage.
●​ Technical Interview (1 hour)
●​ Final Stage
○​ Final interview with Director of Engineering (30 minutes)
○​ Elevate interview (20 minutes)
Please note: While we typically follow these steps, additional interviews may be required in
certain cases. If necessary, the recruiter will inform you and explain the reason for any additional
interviews.
What We Look For
Technical Proficiency
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Competency in Node.js development and ORMs.
In-depth understanding of database transactions and isolation levels.
Proficiency in writing low-level database queries and managing database concurrency.
Familiarity with ACID principles and how they apply to relational databases.
Behavioral Skills
At Deel, we value Genuine Care, Deel Speed, Default Optimism, Thoughtful Frugality,
Exceeding Expectations, and Together Everywhere. These values shape how we work and
interact with each other and our clients.
Preparing for the process
Brush up on your technical knowledge, especially Node.js and databases. Be ready to show off
your problem-solving skills and how you would fit into our team environment. Use this guide to
focus your studying and increase your chances of success!
Home Assignment Preparation
The home assignment will simulate a real-world scenario with a moderate level of complexity.
This should give you a good opportunity to showcase your problem-solving skills, code quality
and ability to design and implement a functional back-end solution.
Key areas to focus on
●​ Endpoint Functionality: Ensure your endpoints return the correct data and handle
errors appropriately.
●​ Data Persistence: For the home task, please use SQLite. There's no need to spend
time setting up a database container — SQLite will handle persistence and simplify
testing.
●​ Transaction Management: Implement database transactions to ensure data
consistency and understand transaction isolation levels.
●​ Security Best Practices: Protect sensitive data with robust authentication,
authorization, and secure coding practices.
●​ Error Handling and Robustness: Implement comprehensive error handling and ensure
your application can gracefully handle unexpected situations.
●​ Project Structure: Structure your project logically with clear separation of concerns.
●​ Coding Practices: Write clean, maintainable code with proper documentation and
adherence to best practices.
●​ Testing: Ensure decent test coverage with unit tests for your back-end logic.
●​ Efficiency and Optimization: Optimize performance through efficient database queries
and consider caching mechanisms.
●​ Documentation and Version Control: Document your project thoroughly and use
version control to track changes.
Additional Tips
●​ Brush up on SQL and data validation mechanisms.
●​ Follow best practices for commits and maintain a clean commit history.
The home assignment is your chance to shine and showcase your back-end development skills.
Technical Interview Preparation
Here are some general tips to help you prepare for your Backend Engineer interview
Master the Fundamentals
●​ Debugging: Practice using profiling tools to identify performance bottlenecks in your
code. Be prepared to discuss strategies for optimizing queries, leveraging indexes, and
implementing caching mechanisms.
●​ Data Structures & Algorithms: Refresh your knowledge of core data structures and
algorithms. Understanding these concepts lays a strong foundation for problem-solving
and code efficiency.
Strengthen Your Architecture Skills
●​ Transactions and Concurrency: Review concepts like atomicity, consistency, isolation,
and durability (ACID) in transactions. Grasp how they ensure data integrity when multiple
users access the system concurrently.
●​ Database Design: Be familiar with relational database design principles for creating
efficient and scalable data models.
●​ System Design: Think about designing systems that are scalable, resilient, and handle
asynchronous operations effectively. Consider modern storage solutions for data
persistence.
Security is Paramount
●​ Security Best Practices: Brush up on fundamental security practices like
authentication, authorization, encryption, and API security. Understand common security
vulnerabilities and how to mitigate them in your code.
Embrace Teamwork and Communication
●​ Collaboration Skills: Reflect on your teamwork and communication skills. Be prepared
to share examples of how you effectively collaborate with colleagues, handle conflicts
constructively, and adapt to changing project requirements.
Testing is Key
●​ Testing Strategies: Familiarize yourself with different testing approaches, including unit
testing, integration testing, and performance testing. Be prepared to discuss how you
integrate testing into your development workflow to ensure code quality and system
reliability.
Embrace Agile Development
●​ Iterative Delivery: Demonstrate your understanding of agile methodologies and iterative
development practices. Be ready to discuss how you prioritize tasks, collaborate with
stakeholders, and adapt to feedback during development cycles.
By focusing on these areas and practicing your technical skills, you'll be well-positioned to
showcase your abilities and impress your interviewer.
Additional Tips
●​ Practice Coding: Regularly practice writing clean, readable, and efficient code.
Consider participating in online coding challenges or open-source projects.
●​ Stay Updated: Keep yourself updated with the latest trends and technologies in
backend development. Explore new frameworks and libraries that might be relevant to
the position you're applying for (if mentioned in the job description).
●​ Communicate Effectively: Throughout the interview, communicate your thought
process clearly and concisely. Be prepared to ask clarifying questions and demonstrate
your problem-solving approach.
Final Stage
For the Final interview with directors of engineering: Use the STAR method to answer our
questions. Provide clear examples from your past projects, team interactions, and achievements
that demonstrate how you embody these values in your work. By telling compelling stories
about your experiences, you'll help us see how well you align on how you can contribute to
Deel's ongoing success.
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Situation: Briefly describe a situation you faced at a previous job where collaboration
was key.
Task: Explain what your specific task or responsibility was within that situation.
Action: Detail the actions you took to collaborate effectively with your team members.
This could involve open communication, delegating tasks, or actively seeking different
perspectives.
Result: Describe the positive outcome of your collaborative efforts. Did you achieve a
specific goal? Did you improve the process?
During this interview, we'll ask questions to see how you reflect our company values in your
work. Here are some tips to help you prepare:
●​ Focus on your ability to think on your feet, make swift decisions, and implement solutions
efficiently while maintaining high-quality standards.
●​ Demonstrate your resilience, positive outlook, and how you inspire and motivate others
during challenging times.
●​ Highlight your proactivity, ownership of your work, and how you consistently strive to
deliver outstanding results.
●​ Emphasize your collaboration skills, ability to build strong relationships regardless of
physical location, and how you contribute to a cohesive team environment.
Elevate interview: As you progress through the interview stages, you will receive a separate
email containing comprehensive information about the "Elevate interview" component. This
email will provide detailed guidance on what to expect and how to prepare effectively. Please
ensure you thoroughly review this document upon receipt, as it will be crucial to your success in
this particular interview phase.
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Ask Questions!
●​ An interview is a two-way street. While Deel is assessing your qualifications, you also
have the opportunity to learn more about the role and our company culture. We
encourage you to ask thoughtful questions throughout the interview process.
●​ Additionally, you can always ask for clarification if something is unclear during the
interview.