Technical Interview:
Definition, Types & Comparison

A technical interview is a type of job interview used by employers to assess a candidate's technical skills, knowledge, and problem-solving abilities for roles in engineering, science, information technology, and software development. This interview format evaluates the depth and breadth of a candidate's knowledge in their chosen field, their ability to apply technical concepts to real-world problems, and how they communicate their thought process under pressure.

Technical interviews serve multiple purposes: verifying that candidates possess the technical skills claimed on their resume, evaluating problem-solving ability and analytical thinking, determining team compatibility, and assessing potential for growth and adaptation to new technologies. The process that candidates use to solve a given challenge is of particular interest to employers, as it provides insight into how they would approach real-world problems at work.

Related terms: coding interview, whiteboard interview, behavioral interview, system design interview

Technical interviews come in various formats depending on the employer, the type of position (full-time, co-op, or internship), and the specific role (such as software development, operations support, plant engineer, or hardware design engineer). The interview format can take place over the phone, online, or in-person, and candidates may experience some or all of these formats during their interview process for a particular role.

Common technical interview formats include pre-interview online assessments, which are timed tests of basic knowledge or coding exercises used to narrow down the field of candidates before or after an initial phone screen. Phone interviews may include a basic screen with general background questions and a technical component where candidates type answers into a shared Google Doc or collaborate on a shared editor like CoderPad. On-site interviews involve answering questions related to knowledge about a particular topic, process, or product, outlining solutions on a whiteboard, making presentations to a team, or writing code on a whiteboard or company-provided computer.

For software engineering roles, the overall technical interview process typically includes an application assessment, a recruiter call, a hiring manager call (sometimes preceded by or replaced by an automated coding challenge), a take-home assignment (if used by the employer), and technical and soft skills interviews often called the "on-site" stage. When a series of meetings are scheduled on a single day, this stage is called the on-site interview even if conducted remotely.

A technical interview can last between one hour and a full day, depending on the demands of the position and the number of candidates. The duration varies by stage: an initial phone screen typically lasts about 30 minutes, technical assessments can range from 1 to 3 hours depending on problem complexity, and onsite interviews can last a full day with multiple technical rounds each lasting from 45 minutes to an hour.

The technical interview process often includes more than one round, encompassing HR, technical, and in-person interview rounds. The entire process from the first interview to the final decision can span several days to a few weeks, depending on the company's urgency and scheduling logistics. For example, top technology companies may budget 4 interviews per hire as they provide a reliable way to understand how a candidate approaches problems and whether they will integrate well with the team.

Technical interview questions are highly specific to the role and typically cover programming languages, algorithms, coding platforms, and data structures. Companies look for candidates who can articulate industry terms and provide examples of their technical skills and knowledge from previous jobs to assess experience level.

Common technical question categories include algorithms questions (such as "Explain how you would implement a sorting algorithm that can handle large datasets efficiently"), system design questions (like "Design a URL shortening service and describe the architecture and components you would use"), debugging challenges, and problem-solving scenarios. For engineering roles, questions might include "Explain how a hybrid vehicle operates" or "How does the strength to weight ratio compare for aluminum vs. steel?"

For data science positions, questions often cover statistical concepts (such as "What is a p-value and how do you interpret it?"), data analysis approaches, and handling incomplete datasets. IT support roles may encounter troubleshooting scenarios and systems administration questions. Additionally, technical interviews often include behavioral questions to understand how candidates work in teams, handle pressure, or manage complex projects, such as "Tell me about a time when you felt your project had an unreasonable deadline. How did you handle that situation?" or "Describe a time when you stepped into a leadership role."

To prepare for a technical interview, schedule blocks of time to practice answering sample questions and problems. The only way to gain confidence in simultaneously explaining your work while solving challenges is through hours of practice. Invite friends to work on coding challenges found in online platforms like LeetCode, which provides over 1000 practice questions, or use interviewing.io for anonymous mock interviews with engineers from top companies.

Review major topics covered in your coursework related to the position you are applying for, and carefully review the job description to be prepared for questions relating to required skills. Research the company to understand the types of problems they solve and what products or services they sell. Be comfortable writing code or demonstrating a process, solution, or design on a whiteboard, and review a few technical projects you have worked on in school or internships to be prepared to discuss your role, contributions, a high-level overview of the projects, any issues that arose, and how you dealt with them.

Additional preparation strategies include reading the job description aloud to catch previously overlooked responsibilities, comparing your resume to the job description to note where it overlaps, practicing describing your work experience and technical skills by talking to a mirror, and researching the company's vision and industry reputation. Review employee feedback about the organization on sites like Glassdoor or Indeed, and browse past interview questions for the role or company. If a skill is listed on your resume, be prepared to answer questions on it or be tested on it.

Think out loud and verbalize your thought process during a technical interview, as this is a critical aspect of the evaluation. Ask clarifying questions to make sure you understand the problem and have all the information you need, as some problems may be intentionally vague or ill-defined to assess your confidence in asking questions and gathering data. Communication is core to everything you do in the tech industry; understanding and communicating problems comes first, while coding is secondary.

Offer multiple approaches to the problem and document your notes and calculations. If using Google Docs during a phone interview, ensure your process is documented even if you don't arrive at a solution. Listen to your interviewer and their suggestions, as they will often try to help if you are going in the wrong direction. You can ask periodically if they have any questions or if you are on the right track. Focus on the process rather than the answer, and if you have no background in a topic, be honest and express your willingness to learn about it.

Do not bluff or guess if you don't know the answer. Take a few minutes to think about it, say that you have not encountered a similar scenario, but you are going to try to work through a process to solve the problem. Many candidates receive job offers even after arriving at the wrong answer because the evaluation focuses on why they were answering a particular question and their ability to explain how they approached the solution. Modern software is created by teams, and team members must be able to effectively communicate technical ideas, so do not sit there quietly during problem-solving.

Common mistakes include not asking clarifying questions when the problem is unclear, poor time management, not testing solutions thoroughly, and being unable to explain the thought process clearly and concisely. Many promising candidates make incorrect assumptions or dive right into the coding part without asking for additional details, then fail the technical interview.

Another frequent mistake is not taking time to fully grasp the challenge before beginning to solve it. Candidates should express their idea and acknowledge it with the interviewer before beginning work. Additional errors include not being honest on the resume or during the interview process, and failing to mention if they have seen a coding challenge before. Bluffing or claiming to have certain skills rather than being transparent about areas needing improvement can also hurt a candidate's chances.

For most technical interviews, business professional attire is expected. This is true for many engineering and technology firms. However, there are exceptions, particularly in the startup and tech space, some west coast firms, and for some software-focused roles.

Candidates should dress according to pre-interview guidelines provided by the company. If in doubt, ask the recruiter about the appropriate dress code. Always choose professional attire, even in video calls, and if uncertain, it is better to err on the side of being more formal.

Ask your interviewer about follow-up information when concluding your technical interview. Make sure you get your interviewer's business card or contact details if you don't already have them, and ask about a projected time frame in which you can expect to hear from them. Asking about follow-up expectations can also act as a transition to additional questions about the next steps in the interviewing process.

Send the interviewer a thank-you letter within one business day of your original interview date. With a technical interview, a thank-you letter gives you the chance to relay important parts of your discussion and which technical topics you enjoyed talking about the most. Make a list of the terms or topics you want to learn more about and use it as a guide in your future professional development initiatives. Continue applying for industry jobs and interviewing with other companies, as you might not hear about a technical interview right away.

A technical interview is often compared to 3 related interview concepts:

Technical Interview vs. Behavioral Interview

Technical Interview vs. Coding Interview

Technical Interview vs. Case Interview