A Comprehensive Guide on How to Prepare For a Coding Interview

If you’ve ever interviewed for a job before, you know the procedure. You’ve applied, they’ve responded positively, and now there’s a set date and time for you and your potential employer to discuss the job and your qualifications.

But if you’ve never interviewed before, or if you’re interviewing for the first time in a different industry, you might be wondering what exactly to expect. And when it comes to fields like software engineering, it might be all the more important to be prepared.

If you’re just setting out on your job hunt in the tech field, you’re likely to come up against a coding interview at some point. We created this comprehensive guide on how to prepare for a coding interview and what you should do before, during, and after the interview.

What is a coding interview?

Coding job interviews are not much different than any other interview, except that you’re expected to show off your technical skills. When it comes to software engineering jobs, a coding interview is an expected step in the hiring process at most tech companies, especially the ones collectively known as FAANG.

They are, however, slightly more complicated than the simple question-and-answer format. In most cases, you’ll be expected to solve a coding problem in real time or submit your work to your interviewer for review.

Components of a Coding Job Interview

The Behavioral Interview

While the technical skills are largely weighted during technical coding interviews, hiring managers are also looking a little deeper. They’re interested in your problem-solving skills, speaking abilities, critical thinking methods, and generally what kind of a person you are.

These soft skills speak volumes about how you’ll perform as an employee, beyond simply doing the technical tasks put before you. Remember, every company you interview with is a living, breathing system. Interviewers want to make sure you’re not only technically brilliant but will fit in with the company’s culture overall.

Most companies have a similar process they follow for job interviews. You may meet with a hiring manager first so they can give you an overview of the job responsibilities and company culture, and so you can let your personality shine. This is sometimes known as a “behavioral interview” or “screening” so that you and the company’s representative can see if you’re compatible. Remember: you’re interviewing the company as much as they’re interviewing you. We want you to find a great job at a company that works with your needs, too.

Some of the most common interview questions you’ll be asked during the early stages of your interview are:

• Why do you want to work here?
• Tell me about a time you had to solve a problem at work.
• What’s your work style?
• What are your career goals?

Be prepared to talk about yourself in a way that highlights your problem-solving skills and accomplishments.

The next steps can vary from company to company and from job to job. You might interview with potential team members or department leaders next to get a deeper insight into the job responsibilities and what they’re looking for in a new team member. You might go straight into the coding interview. No matter what the next steps are, we can help you prepare.

Learn More: Must Have Software Engineering Soft Skills

The Technical Interview

A technical interview is a tool that employers use to vet potential software engineering candidates. These interviews are problem-oriented to test your understanding of dynamic programming fundamentals, algorithms, system designs, syntax, and data structures.

While some companies have adopted similar approaches to programming interviews, they’re not all created equal. Big tech companies like Amazon and Google do not ask the same interview questions as your local startup. And every tech company has its own industry-specific questions. In any case, you’ll be given a series of problems to solve by writing code in real time while talking through your thought process.

Some interviews will be conducted in person, in which case you may be asked to perform a “whiteboard interview.” This involves writing code and solving problems on a whiteboard in front of your interviewers – potentially your would-be boss(es).

Online coding interviews usually involve your potential employer utilizing software designed especially for remote coding tests so you can either do the coding challenge apart from the interview (with a time limit) or work with your interviewer collaboratively.

What Types of Skills are Tested During a Technical Interview?

There are a few commonly asked questions during most coding interviews that you can prepare for ahead of time. Even if you aren’t asked any of these questions, it helps to have a basic understanding of what tech interviewers generally ask.

However, as previously mentioned, every technical interview is different. Companies determine which qualities and skills are most important for them to evaluate the technical acumen of their candidates. Luckily, you may be able to ask ahead of time about the types of skills you’ll be tested on so you can incorporate them into your study. You may also be able to ask about the tech stack the company uses internally.

As part of your coding interview preparation, brush up on these commonly tested skills:

• Algorithms, like bubble, merge, and heap, plus linear search, binary search, breadth-first search, and depth-first search. Also, look for time complexity.
• Data structures, including arrays, stacks, heaps, queues, hash tables, binary trees, and linked lists.
• Programming languages, both those you’re most familiar with and those the company uses in its tech stack.
• Syntax within each of those languages.
• Strings, including how to manipulate them and understand rotation and concatenation.
• System designs are complex, but they’re popping up in more technical interviews these days.
• Recursion for problem-solving methods.

Learn More: Algorithms and Data Structures Every Programmer Should Know

How to Prepare for a Coding Interview: The Different Stages of Coding Interview Prep

Knowing how to prepare for a coding interview is a multi-step process. Let’s break down each step and what you can do to get the most out of your research and practice.

Before the Interview

Practice

Practice makes perfect (or at the very least, it instills confidence). Leetcode is particularly helpful at this stage of your coding interview prep. If you’re not familiar, it’s a forum where software engineers can find practice questions and work through coding problems. Educative is another tool that helps you practice coding in a live online environment.

There’s also strength in numbers. Try pairboarding with a partner while they watch and assist you as you’re solving test cases on a whiteboard. This allows you to practice talking through your method.

Now’s a good time to double down on studying your data structures and algorithms. If possible, schedule a mock interview with someone in your community or with a mentor. Pramp is a service that offers mock interviews and walk-throughs of typical coding interview questions. App Academy graduates have this baked into the 1:1 career coaching that every student receives once they complete their curriculum, and they’re uniquely qualified to do so.

Finally, it’s important to review the code you’ve written in the past. Some companies like to see your programming portfolio of past work, and you should be able to walk them through those projects succinctly. Reacquaint yourself with languages you’re comfortable with, whether you have working Java knowledge, JavaScript proficiency, or extensive Python experience.

Ask Questions

Once you’ve got an interview on the books, make sure to ask the interviewer or hiring manager a few clarifying questions:

• Is there anything about the format I should expect?
• Is there anything about my local coding environment I should prepare?
• What have successful candidates prepared for in the past?

Get as much information as you can ahead of time so you can focus on the parts of the interview that are in your control.

Research

Next, conduct any research you can about the company itself. More established companies like Netflix, Google, and Spotify have dedicated tech blogs written by their engineering team. Within them, they talk about updates to their products and projects the company is working on. You’ll likely manage to find out what tech stack they use internally through these blog posts.

Quora and Reddit are great resources, too, as are Facebook or LinkedIn groups. You will likely find people who have interviewed at the same company or similar. Learn from their experience to find out what types of technical questions the company asked and what the interviewee wishes would have gone differently about their own attempt. If not, create your own post in related forums and take in as much first-hand information as you can.

Additional research definitely doesn’t hurt in the days leading up to a coding interview. Get your hands on literature about technical challenges and research what’s expected of you. In other words, don’t walk in with any lingering doubts. Be confident in the skills you’ve learned and the coding projects you’ve worked on and get comfortable with speaking to your experience.

To sum up, here’s your pre-interview checklist to make sure you’re prepared:

• Ask the hiring manager clarifying questions to prepare you for success.
• Practice, practice, practice…then practice again. Practice solo and whiteboard with friends or mentors.
• Research the company’s tech stack and confer with others who have interviewed there.
• Review code you’ve written previously and re-familiarize yourself with languages you’ve learned.
• Participate in mock interviews through Leet, Educative, or Pramp.

During the Technical Coding Interview

Preparation includes not only what to do before your interview, but also anticipating what to expect mid-interview. Though the questions may be new to you, the principles behind restating the problem at hand and asking clarifying questions should be old hat. You’ll be familiar with doing both of these from your mock interview prep.

Articulate your thought process and speak out loud as you’re working. If you change languages mid-problem, explain why. Let them know how you came to conclusions or found solutions. Behavioral cues are just as important as technical acumen. Remember: they are hiring you as a whole person, not just a coder.

After the Technical Coding Interview

Once you’ve completed a technical interview and left the room (either figuratively or, quite literally, the onsite interview room), take a deep breath and pat yourself on the back. Technical coding interviews are challenging. They’re designed to put you under pressure. You’ve put weeks of prep work into a 60-minute presentation and you deserve to feel accomplished.

Within 48 hours of completing your technical interview, send an email to your interviewers and hiring managers thanking them for their time. Mention how you think you’ll be a good fit for the job and the company. You should also ask for feedback and notes on your interview, regardless of whether you move forward in the role or not. Make sure to personalize your email so they know you didn’t copy and paste something you sent to everyone.

Finally, take some time to reflect, both on your own performance and the team at this company. Now that you’ve gone through a few steps, does the company feel like a good fit for you? Remember, you’re interviewing them as much as they’re interviewing you. Don’t take a job out of desperation. If an offer were to be made, would you take it? Is it your dream job?

Making a pros and cons list isn’t a bad idea to get your thoughts down on paper after every coding interview. Especially if you’re interviewing frequently, it will help you keep track of the different organizations and what you like and dislike about them.

The Best Coding Interview Prep Advice: Practice, Research, Then Practice Again

Cracking the technical coding interview process isn’t easy. Even seasoned professionals prepare for them well in advance, even before they’ve been invited to interview. For newer and mid-level engineers, giving yourself lead time to practice your hard skills, gain confidence in your soft skills, and do enough research to solidify both skill sets will afford you more confidence and hopefully, a better performance.

In addition to the above resources we mentioned, we invite you to try App Academy Open entirely for free if you want a refresh on core software engineering topics. It will help strengthen your understanding of languages you may already know, as well as reaffirm your comfortability with those data structures, algorithms, and syntax you need to have nailed down prior to your interview.

The App Academy Advantage: Career Prep & Support

Since 2012, App Academy has been helping coders, programmers, and software engineers prepare for jobs in tech. Our alumni have found jobs in over 2,000 tech companies, including some of the biggest names in the world: Meta, Microsoft, Google, Amazon, Netflix, and more. App Academy was designed by industry professionals, for future industry professionals.

Our bootcamps prepare you for your future as a tech professional by giving you projects that build your portfolio and include expert coaching to guide you through every stage of your job search, from mastering your pitch to presenting yourself to employers. We have the resources to help you prepare for and kickstart a fulfilling new career, regardless of the bootcamp you choose.

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