Duo Security Interview Questions | Glassdoor

Duo Security Interview Questions

Interviews at Duo Security

91 Interview Reviews

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  1. Featured Interview

    Helpful (11)  

    Customer Success Manager Interview

    Anonymous Employee in London, England (UK)
    Accepted Offer
    Positive Experience
    Average Interview

    Application

    I applied online. The process took 2 weeks. I interviewed at Duo Security (London, England (UK)) in December 2016.

    Interview

    This has been by far the best interview process I've ever been part of and I was planning to write a positive review regardless of whether I had an offer or not. I applied through the website on a Thursday, received an e-mail to set up a call with the recruiter the following Monday, and two weeks after that first call I had an offer!

    Linda, the internal recruiter, is efficient, kind, smart, supportive, honest, down-to-earth, and has just made it such a pleasure to deal with Duo from start to finish - any company who needs to make a good first impression on candidates should just work on cloning her, really. Right from the start we set clear guidelines on how best to work together throughout the process (open communication, transparency on other job offers, approachability, open feedback loops) and I can't stress enough how nice it was to work like that.

    Everything was well-organised and I always felt like whoever I was speaking to actually cared about what I was looking for in a job, rather than just trying to find out whether I ticked their boxes. I met with various people in the Customer Success department (both US & UK), as well as others in the London office, so was able to get a well-rounded view of what working at Duo would be like. You can definitely see and hear that everyone who works there is excited to be part of Duo and shares common goals and values, but was also honest when I asked what would potentially put someone off joining Duo (answer was generally "people who aren't used to a start-up environment may take a while to adapt" - very fair). Also - the hiring manager was SO helpful in the phone call when I asked what I could study to set myself up for success in the role if I moved forward, and took the time to take me through the most relevant parts of the documentation on the website. Really refreshing when I thought he would just throw a few words and topics at me with an "off you go" approach...by far exceeded expectations already.

    All in all - can't wait to get started!

    Interview Questions

    • How do you approach situations where your UK client may be blocked from doing what they need to, but you have to contend with a time difference and wait for support in the US to move forward with a solution?   1 Answer
    • What is your familiarity with endpoints, SAML, 2FA?   Answer Question

    Duo Security Response

    Oct 18, 2017 – Director of Recruiting

    Thank you for taking the time to share your interview experience. We are very happy to hear your interactions with Linda and the whole UK team were positive, and that you chose to join the Duo team... More


  2.  

    Software Engineer Interview

    Anonymous Interview Candidate in Ann Arbor, MI
    Declined Offer
    Positive Experience
    Difficult Interview

    Application

    I applied through other source. The process took 2 weeks. I interviewed at Duo Security (Ann Arbor, MI) in March 2015.

    Interview

    I was introduced to Jon at Duo, who skyped with me to determine whether or not there was a fit on both sides.

    This was followed by a Technical Phone Screen with Engineering Managers. This covered a variety of questions ranging from general theory to specifics of the technologies I listed on my resume.

    Onsite Interview:
    During my onsite I had non-technical interviews with the Director of Engineering and the CEO in the morning, followed by lunch with the CTO. Everyone was very impressive and it is very obvious that Duo is committed to building a high quality team of people to work with.
    The afternoon was two technical interviews, each with a different engineering manager. One interview covered front end engineering (JS/HTML/CSS) and the other covered Algorithms/Data Structures. Both were challenging and on par with the companies I've interviewed with in San Francisco.
    The day ended with an exit interview and dinner with the team.

    The recruiters and schedulers at Duo did a great job of keeping me in the loop and were extraordinarily kind in scheduling my trip over a weekend so I could spend some time with family I have in MI (I mention this because I think it is a microcosm of the great culture they are building there).

    Overall the process, the team and the offer were all great. I'd highly recommend Duo Security to anyone looking for a great place to work.

    Interview Questions

    • Write an algorithm to reverse a string in place.   2 Answers
  3. Helpful (5)  

    Software Engineer Interview

    Anonymous Interview Candidate in Ann Arbor, MI
    Declined Offer
    Positive Experience
    Difficult Interview

    Application

    I applied in-person. The process took 4+ weeks. I interviewed at Duo Security (Ann Arbor, MI) in May 2015.

    Interview

    I couldn’t have asked for a better interview process at Duo. I’ll start by saying that my situation was a little unique; I was working at a San Francisco based company looking to move back to Michigan, where I’m from.

    As you might imagine, this poses some logistical problems. Duo was very accommodating during every step of the process, from working with me around the time difference all the way up to booking me a hotel room and flight that worked with my very, very tight time schedule (it turns out it’s hard to fly across the country on the sly). The recruiter I was working with was amazingly helpful and transparent; I never wondered where I was in the process, which, as someone who has interviewed with quite a few tech companies, was a very welcome change.

    As for the actual interview process, it pretty much followed the standard tech company format. I had three phone screens, none of which were terribly technical. I had phone screens with two engineering managers and the director of engineering, and it seemed the purpose of these screens was to determine a fit both ways. We talked about my experiences at my current company and the projects I would be working on at Duo. Overall, the phone screens were pleasant, and gave me a good idea of what Duo was all about.

    Next came the onsite interviews. As I mentioned earlier, this involved setting up a flight that would allow me to only miss one day of work here in California, a task that Duo executed admirably. I couldn’t have asked for a better in-the-door experience. The front desk greeted me warmly and saw to it that all of my needs were attended to right away. After that, the day began with a 45 minute chat with Dug Song, the CEO and co-founder of Duo. It was a good way to ease me into the grueling interview gauntlet that followed.

    Following Dug, I had two technical interviews with the two engineering managers I had spoken to on the phone, and one less technical interview with the director of engineering, all before lunch. Each interview was 45 minutes long. The interviews with the two engineering managers were fairly standard; we started off by chatting about my experiences, about the things their teams were working on, and then launched into the whiteboard section. The whiteboard questions were pretty comparable to interview questions I’ve had in the past.

    My interview with the director of engineering was unlike any other interview I’ve ever had, in a good way. We started out with the usual chit-chat about my experiences and the like. After a few minutes of that, however, we quickly shifted gears into talking about the greater engineering challenges that Duo faced as an organization. My interviewer was very keen on hearing my take on the issues that the whole of Duo engineering dealt with, and he took notes and asked insightful questions about my answers. I got the sense that he was taking my suggestions seriously, which was pretty cool, coming from the director of engineering. In fact, we ended up continuing the interview at the end of the day in an Ann Arbor coffee shop.

    With the technical interviews out of the way, it was time for lunch. I will say that I don’t think it is Duo’s normal policy to cram all of the interviews before lunch, but as I had a flight to catch, it was the only way it would work -- another example of Duo accommodating my (admittedly somewhat unreasonable) constraints. I took lunch with two rank-and-file Duo engineers at Grizzly Peak, a very tasty restaurant within walking distance of Duo’s office. The two engineers were very friendly and personable, and we had a good time at lunch. It was very nice to take some time to unwind a little bit and learn more about what the day-to-day of working at Duo was like.

    The final stop of the interview train was with the recruiter I had been working with from the beginning. There, we went over HR-ey stuff like benefit packages and so on. Afterwards, we took a tour of the office and met a few more friendly Duo employees. As I said earlier, this recruiter had been a joy to work with, and I left Duo with a very positive impression of the place and the people who work there.

    We wrapped up the day with the coffee shop interview with the director of engineering I mentioned earlier, and then I was promptly whisked to the airport to catch my flight and my breath.

    Interview Questions

    • Write a function that takes two strings as inputs and returns the set of common characters between them.   Answer Question

    Reasons for Declining

    Ultimately, I ended up turning down the offer due to some unique factors involving my current employer. I would like to call out Duo’s handling of the situation; I was upfront with them about what was going on, and they handled it amazingly. I never once felt like I was pressured into making a decision, and I felt like Duo’s recruiter genuinely cared about what was best for me as well as the company. For giving me some relief during what was a very stressful time in my life, I can’t thank them enough. Interview with Duo. Seriously. You won’t regret it.


  4.  

    Software Engineer Interview

    Anonymous Interview Candidate in Pittsburgh, PA
    No Offer
    Positive Experience
    Average Interview

    Application

    I applied through college or university. The process took 1 day. I interviewed at Duo Security (Pittsburgh, PA) in February 2016.

    Interview

    Two hours interview, 1 hour technical, 1 hour behavioral. Technical questions are some general coding questions. Behavioral basically is to get to know what kind of person you are. The people who interview me were really nice and serious, they took notes of everything you said. And were glad to answer all questions I had.

    Interview Questions


  5. Helpful (9)  

    Software Engineer Interview

    Anonymous Interview Candidate in Ann Arbor, MI
    No Offer
    Positive Experience
    Average Interview

    Application

    I applied online. The process took 5 weeks. I interviewed at Duo Security (Ann Arbor, MI) in January 2016.

    Interview

    I submitted an application on Duo Security's website. It took them a week or two to get back to me. Their recruiter (Courtney) was competent, responsive, and pleasant to communicate with. The recruiter set up a phone chat to tell me about the company, ask questions, and get to know me a little bit. I got a technical phone screen about a week later. It was technically-oriented but I don't think it was meant to be terribly challenging; it felt like its purpose was to rule out candidates who simply can't code. Perhaps 2 weeks later I got an on-site interview. The on-site interview had three parts: a chat with some recruiters at the beginning, a technical interview, and an experience/teamwork interview. The technical interview was more difficult, but still not very hard. It felt awkward; the person who conducted it did not talk very much. I stumbled with one of the questions because I tried to jump straight to the in-place solution of least time complexity, and I tripped up. Don't do what I did; I don't think it was apparent to my interviewer that I knew how to solve the problem and was working toward a solution. Try to solve the problem with bad time or space complexity first so they know you've got a brain. The next interview asked a lot of questions about my history of working with teams. It was pretty good. Lots of deep, open-ended questions. I did not receive an offer, but I did get helpful and (AFAIK) honest feedback: I was a great cultural fit and had a strong technical foundation but lacked the experience needed to fit in to one of their teams. I think it was a good experience overall, but I felt pretty frustrated after the technical interview because of my mistake. I'm not going to list any of the technical questions, but it's safe to say you would find them or similar questions just about anywhere you look.


  6.  

    Software Engineer Interview

    Anonymous Employee in Ann Arbor, MI
    Accepted Offer
    Positive Experience
    Average Interview

    Application

    I applied online. The process took 1 day. I interviewed at Duo Security (Ann Arbor, MI).

    Interview

    Duo takes hiring seriously, and the interview process was extremely solid. An in-house recruiter immediately made me feel at ease, and everyone that I talked to during the process was very friendly and enjoyable to talk to. I had originally applied for a position much earlier in the year, but was told that I would likely be a better fit for a different team within the company, and that they would keep my info on file -- I sort of thought this was a kind of way of turning me down, but about 6 months later they called me up and said a position had opened up, and they wanted me to come in to interview.

    The interview took about a full day, and I spoke to two managers, a director and a VP of engineering. There was a technical interview (standard comp. sci questions, including big O notation and unit tests), a behavioral interview, and two more conversational interviews in which they got a feel for my technical background and personality, and gave me lots of opportunities to ask questions and assess more about the company.

    Duo seems to be full of people who are actively working to make sure that the rapid growth the company is experiencing happens in a meaningful way -- they take a lot of pride in ensuring that the culture moves in a positive direction, and one value that was frequently touched on was "Be Kinder Than Necessary," and it showed in the sort of interactions I experienced in their office.

    Interview Questions


  7.  

    Software Engineering Interview

    Anonymous Employee in Ann Arbor, MI
    Accepted Offer
    Positive Experience
    Average Interview

    Application

    The process took 2 weeks. I interviewed at Duo Security (Ann Arbor, MI) in January 2015.

    Interview

    The interview process consisting of meeting with both technical and managerial Duo employees. All I can say is that the employees were extremely candid and welcoming, and made the whole process, which lasted three hours, very enjoyable and fly by. The process consisted of one 40 minute technical interview, and two hour+ long non-technical interviews.

    Interview Questions

    • Given two strings as inputs, write a function that returns all the characters the two strings have in common.   Answer Question
  8.  

    Software Engineering Interview

    Anonymous Employee in Ann Arbor, MI
    Accepted Offer
    Positive Experience
    Average Interview

    Application

    I applied through college or university. I interviewed at Duo Security (Ann Arbor, MI) in January 2017.

    Interview

    I don't think I've ever had a better interview process. I met with one of their recruiters, Courtney, at my University career fair. She set up a phone call for us the following week, where we talked about the company and the internship program that was offered. From there she scheduled a phone interview later in the week. I had made her aware that I had a competing offer, so she expedited the whole process which was incredible. The phone interview was 15-20 minutes talking about my programming experience and projects, then we did two programming problems using an online tool. Nothing too crazy. The next day I was told that I had moved onto the next round, an on-site interview the following Monday. That was where I met several members of the team for a 1 hour behavioral interview, 1 hour technical (white board) interview covering a few different programming concepts, and the last hour spent meeting with one of the people in charge of the internship program, as well as taking an office tour. I was made an offer less than two days later.

    Overall, the team at Duo was exceptional throughout the entire process. Everyone seemed so incredibly excited about the work that they do.

    Interview Questions

    • Given two strings with all but one character in common (one character missing from the first string), return the character that is in the 2nd string but not in the 1st.   Answer Question

  9.  

    Integration Specialist Interview

    Anonymous Employee in Ann Arbor, MI
    Accepted Offer
    Positive Experience
    Average Interview

    Application

    I applied in-person. The process took 3 weeks. I interviewed at Duo Security (Ann Arbor, MI) in March 2015.

    Interview

    Duo does a fantastic job with interviews.

    I've attended many of Duo's Tech Talks, which are events where security professionals from different companies come in and give presentations on different topics. Usually at these events someone from Duo will mention that they are hiring and talk about a few of the positions.

    At the end of one of the tech talks I connected with someone from their People and Culture (their version of HR) who later got in contact with me via e-mail. We connected and I ended up having a short half hour long interview for one of their Solution Engineer positions. During this time, the manager I spoke with got the feeling that I would be more suited for a different position within the company. They got me in contact with a different P&C member.

    This P&C employee had a 30 minute phone conversation with me, I believe this was to see if both myself and the company would be a good fit together. Once we spoke, we scheduled an all day in-person interview for the following week. Duo sent me a very nice itinerary about the day, how I should dress, directions to the building, and even where to park.

    In Person Interview:

    I arrived for the interview on time. I was greeted at the door by the P&C employee I had been conversing with. She asked me if I would like anything to drink and told me where I could hang up my coat. She then chatted with me for a few minutes before leading me a conference room.

    The first employee I was interviewing with was already there and ready to go. She had a copy of my resume and a set of questions. I was quite nervous at first but the company is very good about making you feel relaxed and welcome throughout the entire building. We spoke about my resume, my skills and questions she had regarding information off of my resume. This went on for about 75 minutes before the next employee came in.

    The next employee would be my direct manager. Again similar questions, asking me about my resume, general conversation. Very interested in both my technical skills and my interpersonal skills. This went on for about 75 minutes as well. Two more employees came to the door and we headed off to lunch. This was a very relaxed lunch, just general conversation, light work chat. I believe this was to verify once again that you (the potential employee) would fit in with the company's culture. Definitely a fun experience.

    Once back I met with two more employees for 75 minutes each, the last being the director of the department I would work for. He was very interested in what I wanted to get out of working at Duo, how I could grow within the company, and what questions I had about Duo.

    Finally I met with the P&C employee again for about 45 minutes who explained a lot of their benefits to me, asked if I had any other questions, and told me timelines and next steps.

    It was a great interview, very in-depth but made you feel comfortable and allowed time to for you to ask questions about the position, company, and to get a feel for what it would be like to work there.

    Interview Questions

    • Do you have any experience with ADFS, if so, please explain your experience with it.   Answer Question

  10.  

    IT Manager Interview

    Anonymous Interview Candidate in Ann Arbor, MI
    No Offer
    Neutral Experience
    Easy Interview

    Application

    I applied online. The process took 2+ months. I interviewed at Duo Security (Ann Arbor, MI) in March 2014.

    Interview

    Applied online, and was contacted by a recruiter a couple of weeks later. There was a phone screen with the recruiter, then one with the hiring manager, then an in-person interview with a technical peer and the hiring manager, then another in-person interview with one of the company's founders.

    With each person I spoke with, the job they were describing became less, and less of a management role, and more of a helpdesk role. By the time I spoke with the co-founder, the "IT Manager" might have "up to one employee by the end of the year", and everything else was helpdesk and simple network administration. It was pretty clear that people weren't on the same page.

    I appreciate that they want to heavily vet every candidate, because they're small. But, I really would have appreciated it if they hadn't wasted so much of my time.

    Interview Questions

    • I was really surprised here, because nobody really asked me anything difficult. The technical questions were cut and dry, and the soft questions were your standard "Describe a difficult situation..." that everyone asks.   Answer Question

  11. Helpful (6)  

    Marketing Interview

    Anonymous Interview Candidate in Ann Arbor, MI
    No Offer
    Neutral Experience
    Easy Interview

    Application

    I applied online. The process took 4 weeks. I interviewed at Duo Security (Ann Arbor, MI) in July 2015.

    Interview

    Quick chat with the recruiter on the phone a few days after applying online. Met with the hiring manager on the phone a day or two later. He seemed interested in moving forward, so he informed me that the next step was to present three case studies via a web conference, which seemed awfully amateurish considering the position. It was obvious that they were fishing for some free consulting.

    Went to Ann Arbor for a final round of interviews with various leaders (seems like I met with half the company!) I presented a generic marketing 101 type of case study about how to market a hypothetical product to the hiring manager, CTO and head of product management. I then moved to a series of one on one interviews. I enjoyed my in-depth conversations with the hiring manager, CTO, HR rep, various members of the marketing team, SE manager and the head of Product Management. The interview with the COO was bizarre. He decided a minute or two into our interview that he'd take off his shoes and massage his feet (thankfully still with socks on) right in front of me, after which he rested them on a chair right next to me. Either he was being completely rude/inappropriate or it was some sort of a test. I just ignored his behavior, answered his questions and moved along to the next person.

    In the end I didn't get an offer. The recruiter said that they decided that they wanted someone with startup experience, which is bizarre since I told them from the beginning that I'd never worked at a startup.

    Interview Questions


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