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Software Engineer Interview Guide

Interview Guide Oct 27

Detailed, specific guidance on the Software Engineer interview process - with a breakdown of different stages and interview questions asked at each stage

The role of Software Engineer

Software engineers are responsible for creating and maintaining software products that span from everyday websites and mobile apps to complex operating systems and databases. The field has evolved, especially with the proliferation of software tools and products. 

Software engineers today have a diverse range of projects to work on, from websites to operating systems. Even with respect to future prospects, there are some exciting trends to keep an eye on. Artificial Intelligence (AI) and Machine Learning (ML) are definitely shaping the landscape. Low-Code Development is simplifying the way companies create software, and Cloud Computing is revolutionising how they host and scale applications. Blockchain technology is gaining traction too.

While salaries in different domains and companies can vary, an average of $175,000 is a solid number, especially with the increasing demand for skilled software engineers.

Let's take a look at the comprehensive software engineering interview process.

Software Engineer Interview Guide

There are four main rounds in the SWE (Software Engineering) interview process:

  • Phone Screens (usually 2)
  • Online Coding Assessment
  • (Sometimes) Take-Home Assignment
  • Onsite Interview (3–5) 
Relevant Guides

Software Engineer - Phone Screens

Overview

Phone screens are typically the first step in the software engineer interview process. This initial phone screen is typically with a recruiter, and it serves as a way to get to know you slightly better. The recruiter will inquire about your interest in the role and discuss the basic requirements. 

They might ask:

  • Tell me about yourself.
  • What interests you about this role?
  • Have you worked with [specific technology or skill] before?
  • What are your salary expectations?

If it's a match, they help set up the next interview, which is often another phone screen but with the hiring manager. Here, they'll dive deeper. They could inquire about:

  • Your technical background and experiences.
  • A project you're particularly proud of and your role in it.
  • How you approach problem-solving and collaboration.

This stage is also your chance to dig deeper into the company, the role, and the responsibilities. 

These rounds are your chance to ask questions and gather more information about the company and the role. 

The hiring manager might also inquire about your skills.

Software Engineer - Online coding assessment

Overview

These usually come early in the process. You're given an algorithm problem with clear inputs and outputs, and you have to write code in an online coding interface to solve it. For instance:

  • Given an array, find the two elements that sum up to a specific target.
  • Reverse a linked list.
  • Implement a basic data structure like a stack or queue.

Platforms like HackerRank are commonly used for this. 

It's a good idea to practise on platforms like LeetCode to sharpen your problem-solving skills. Just be aware that in HackerRank, you might need to handle input and output through stdin and stdout, which can be tricky if you're not familiar with the APIs.

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Software Engineer - Take-home assessment

Overview

It's understood that algorithm questions in interviews might not always reflect the day-to-day job tasks. Take-home assignments are a great alternative, as they let candidates showcase their software design skills on larger projects in a real-world scenario.

However, it's worth noting that this approach can be time-consuming for both candidates and companies. Larger corporations tend to stick with algorithm questions due to the high volume of applicants. Take-home assignments are more common in startups and smaller companies. Here are a few example assignments candidates have reportedly been given:

  • Flights Listing App
  • E-commerce Website
  • Social Media Dashboard
  • Food Delivery Service
  • Kanban App
  • Snake Game

Software Engineer - Onsite Round

Overview

The on-site interviews typically consist of technical interviews, which involve coding and system design, as well as behavioral and cultural-fit interviews. Sometimes, they also have on-site skills tests, which are crucial to ensure that you can effectively handle the responsibilities of the role.

Technical Rounds

Coding Round

During the coding portion of the interview, you'll be asked to solve coding problems in front of the interviewers. This is a great way for potential employers to understand your problem-solving skills, thinking process, strengths, and applied knowledge.

You're typically given to tackle two to three coding problems, where you need to explain your approach as you go along.

Additionally, language knowledge can be a significant part of the interview. If the role you're applying for requires expertise in a specific programming language, be prepared to answer questions about your experience with that language and potentially solve problems using it.

System Design

Another important aspect is software architecture and system design. You may be presented with a high-level concept and a set of parameters or limitations and asked to describe how you would design a system within those constraints. This test assesses your ability to apply your knowledge of software architecture to practical scenarios. Be prepared to articulate your design decisions clearly.

For both the technical rounds, it's essential to prepare thoroughly by reviewing your coding skills, understanding software architecture principles, and being well-versed in the programming languages relevant to the position.

Behavioural Round

This one delves into your personality. The behavioral interview is crucial as it offers employers insights into how you're likely to behave in their work environment, helping them determine if you're a good fit.

Behavioral Interview questions are pretty consistent across different industries because they aim to gauge your workplace behavior. They might ask about your responses to certain scenarios, your self-assessment of skills, and your work-related values. 

However, the questions related to company culture fit can vary significantly from one company to another. This is because they are tailored to the specific culture and work environment of the company you're applying to. 

Be prepared for questions that explore what you seek in a workplace and how much importance you place on the company's mission and values. Be sure to research the company culture beforehand to answer these questions effectively.

Interview Questions

  • Do you have experience with [specific programming language]? Can you solve this problem using it?
  • Describe how you would design a scalable system for [specific scenario] with the given constraints.
  • Tell me about a challenging situation you faced in a previous job. How did you handle it?
  • Can you describe a time when you had to work on a project with a tight deadline? How did you manage it?
  • What do you consider your greatest strengths in a professional setting, and can you provide an example of when you demonstrated them?
  • How do you handle conflicts or disagreements with team members?
  • Implement a data structure for a specific use case, like a priority queue or a hash table.
  • Write code to perform a complex algorithm, such as Dijkstra's algorithm or A* search.
  • Given a real-world problem, design an object-oriented solution with classes and methods.
  • Solve a coding problem that involves multiple components and classes.
  • Explain the time and space complexity of your code in detail.
  • Design a distributed system for a social media platform with millions of users.
  • Explain the architecture of a large-scale e-commerce website, including load balancing, caching, and data storage.
  • Design a recommendation system for a streaming service like Netflix.
  • Describe how you would build a fault-tolerant and scalable messaging service like WhatsApp.

Here are some tips to help you crack those interviews. 

  • First and foremost, start your preparation early. The more time you invest, the better you can excel in both technical and behavioural sections. Effective time management is crucial – it's not just about getting the right answer, but doing it within the given time limit. Timed mock tests are your friend.
  • Practice, practice, practice. This can't be emphasised enough. Solve coding problems on paper, whiteboards, and computers. Analyse your problem-solving approach to improve. Learning about the company is often overlooked. Research the organisation, its projects, and goals. This knowledge will set you apart and help you ask relevant questions during the interview.
  • Have a company-specific approach. Tailor your preparation to align with the company's values and expectations. 
  • Finally, our most important tip: Mock interviews—they are invaluable. Practice with technical experts from your target companies—this is possible with Prepfully. You can book a session with SWEs right here. Get feedback, identify areas for improvement, and set yourself up for success. 

Skills and Qualifications Required for a Software Engineer

Here are the skills and qualifications that a software engineer requires.

  • A Bachelor's Degree in Software Engineering provides a competitive advantage, demonstrating knowledge and experience in developing complex systems. It offers foundational knowledge and specialisation in areas like network administration, software security, and user interface design. Often, a bachelor's degree is a minimum requirement for higher-level roles.
  • Software engineers need a mix of technical and non-technical skills, including proficiency in languages like JavaScript, Linux/Unix, and more, as well as the ability to transform requirements into designs, analyse complex technical information, and write detailed technical specs. Soft skills like communication, collaboration, problem-solving, organisation, time management, and project management are equally vital
  • Internships which have helped you build skills, connections, and professionalism in software engineering can be a huge plus, especially if you're a fresher.
  • Entry-level experience involves working on small projects or components of larger projects, understanding business needs, coding, debugging, and testing
  • Software engineers should consider industry-specific certifications such as AWS Certified Developer, MCSD, OCJP, and CCNA to demonstrate expertise and stay updated on industry trends.
  • For career advancement, a Master's Degree in Software Engineering or a related field can provide specialised skills and open doors to higher-level positions.

Frequently Asked Questions