Facebook Interview Questions | Glassdoor

Facebook Interview Questions

Updated Aug 22, 2017
3,092 Interview Reviews

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  1. Helpful (1345)  

    Software Engineer Interview

    Anonymous Employee
    Accepted Offer

    Interview

    phone interview starting with introducing yourself followed by two code questions.
    The first coding question is very standard coding question and the second one is
    a little more related to facebook's certain functionality


  2. Helpful (277)  

    Data Scientist Interview

    Anonymous Interview Candidate
    No Offer
    Neutral Experience
    Difficult Interview

    Interview

    One HR interview, one takehome data challenge, one shared screen with SQL and one onsite with several 1:1 interviews. They check your coding skills and product sense via the takehome, your sql skills via the shared screen interview and machine learning theory as well as product sense during the onsite.
    They let you choose the language for the takehome and onsite there is no coding on the board. So you just need to know one language (whichever you want, although I think they prefer R or Python) + SQL. No C++/Java/etc stuff and no CS algo questions.

    Interview Questions

    • Data challenge was very similar to the ads analysis challenge on the book the collection of data science takehome challenge, so that was easy (if you have done your homework).

      SQL was: you have a table where you have date, user_id, song_id and count. It shows at the end of each day how many times in her history a user has listened to a given song. So count is cumulative sum.
      You have to update this on a daily basis based on a second table that records in real time when a user listens to a given song. Basically, at the end of each day, you go to this second table and pull a count of each user/song combination and then add this count to the first table that has the lifetime count.
      If it is the first time a user has listened to a given song, you won't have this pair in the lifetime table, so you have to create the pair there and then add the count of the last day.

      Onsite: lots of ads related and machine learning questions. How to build an ad model, how to test it, describe a model. I didn't do well in some of these.   20 Answers
  3. Helpful (104)  

    Data Scientist Interview

    Anonymous Interview Candidate in Menlo Park, CA
    Declined Offer
    Negative Experience
    Difficult Interview

    Application

    I applied online. The process took 6 weeks. I interviewed at Facebook (Menlo Park, CA) in February 2017.

    Interview

    I applied online in late December and then spoke to a recruiter for about 15 minutes in early January. I was scheduled for an in-person interview in mid January where I interviewed with one data scientist in a 1:1 interview for an hour for the first round. Another recruiter then called me for a 30 minute prep for the 2nd round. The final, 2nd round interview was about 5 weeks later in late February, with 6 data scientists over 4 hours in the afternoon. I got an offer but it was for a lot less than I was expecting, and we couldn't bridge the gap enough for it to be worth it.

    Everyone seemed relatively nice, although I could tell that a lot of the questions are really designed to trip you up, like they want you to miss some detail or edge case. My advice would be to pay attention to every little bit of minutiae regarding the question, make sure you're staying on task, write on the whiteboard, and explain your thoughts. Industry word is that data science at Facebook is not what it once was and is more of a product data analyst role now, so make sure you're really into Facebook products because that's what you'll be analyzing.

    Also, I didn't get a single question about dice, cards, or any other brain teaser type questions. All these mentions of NDAs are missing the point of Glassdoor, people can be a little more verbose than "various questions". You can't trademark an interview question or claim it's a trade secret.

    Interview Questions

    • How would you measure the health of Mentions, Facebook's app for celebrities? How can FB determine if it's worth it to keep using it?

      If a celebrity starts to use Mentions and begins interacting with their fans more, what part of the increase can be attributed to a celebrity using Mentions, and what part is just a celebrity wanting to get more involved in fan engagement?   6 Answers
    • There is a table that tracks every time a user turns a feature on or off, with columns user_id, action ("on" or "off), date, and time.

      How many users turned the feature on today?
      How many users have ever turned the feature on?
      In a table that tracks the status of every user every day, how would you add today's data to it?   8 Answers
    • If 70% of Facebook users on iOS use Instagram, but only 35% of Facebook users on Android use Instagram, how would you investigate the discrepancy?   5 Answers
    • How do you measure newsfeed health?   2 Answers
    • If a PM says that they want to double the number of ads in Newsfeed, how would you figure out if this is a good idea or not?   3 Answers
    • We have two options for serving ads within Newsfeed:
      1 - out of every 25 stories, one will be an ad
      2 - every story has a 4% chance of being an ad

      For each option, what is the expected number of ads shown in 100 news stories?
      If we go with option 2, what is the chance a user will be shown only a single ad in 100 stories? What about no ads at all?   12 Answers
    • How do you map nicknames (Pete, Andy, Nick, Rob, etc) to real names?   3 Answers
    • Facebook sees that likes are up 10% year over year, why could this be?   4 Answers
    • How many high schools that people have listed on their profiles are real? How do we find out, and deploy at scale, a way of finding invalid schools?   4 Answers

  4. Helpful (43)  

    Software Engineer Interview

    Anonymous Interview Candidate in San Francisco, CA
    No Offer
    Neutral Experience
    Average Interview

    Application

    I applied online. I interviewed at Facebook (San Francisco, CA).

    Interview

    Standard computer science/algorithms phone screen interview.

    I've been a few years in my current job, and I have decided to try the job market again. My resume is impressive, I haven't padded it in any way, I've led software projects to release on time, and I'm finding it easy to get as far as phone screens, but no further.

    This isn't a criticism of Facebook itself, rather of the whole Bay Area software engineering scene - since the last time I went for interviews, there seems to be a much bigger focus on getting the initial computer science/algorithms questions correct on the first go. Miss an edge case that the interviewer brings up, you're toast. Misplace a < instead of <= in an iteration, you're toast even if you find it yourself. Take longer than 20 minutes per question, you're toast. Try to recreate from first principles an algorithm you haven't thought about since you graduated, or never, ever used in your work, you're toast.

    I've interviewed many people in my current job, and never regretted recommending employment to any of them. Every single one of the people I've recommended have made mistakes in their coding tests, and every one of them managed to find the errors when I pointed out that they had made a mistake. Perhaps I have lower standards, but when I interview, I look for how the interviewee recovers from a mistake, not that they are able to regurgitate something they learned from reading over Glassdoor interview questions.

    Or maybe I just come across badly on the phone. Hard to say.

    To recreate the process, go to leetcode and try some of the medium/hard exercises. If you can't complete it in under 20 minutes, and you have to redo some work to cover all the edge cases on submitting the solution, you can be sure that in an interview employers will thank you for applying, praise you for your impressive resume, and tell you no thanks.

    Interview Questions

    • Variation of standard algorithm question. Corrected code on being given edge case. Took 25 minutes to get satisfactory answer - probably too long for the interviewer.   3 Answers
    • Second question was a dynamic program question - I knew how to find the solution but hadn't even thought of the algorithm for several years. Was unable to complete the solution in the remaining 20 minutes.   2 Answers

  5. Helpful (68)  

    Product Manager Interview

    Anonymous Interview Candidate
    No Offer
    Positive Experience
    Difficult Interview

    Application

    I applied online. I interviewed at Facebook in February 2017.

    Interview

    I applied online and was contacted for a Product Manager position in either Seattle or Menlo Park by HR. After the phone screen, HR explained I could be hired on for an allocated role or go through the generalist process (where you would get to take a couple weeks after you get hired to learn about Facebook in bootcamp & choose a team). I chose the generalist process, and HR set up 2 45-minute video interviews (product sense & execution). After the video interviews, HR sent me an email to set up a phone call, which she then told me that they would not be moving forward and gave me feedback on what could have been improved.

    Video interviews were fun and I enjoyed talking to the interviewers. Next time, would definitely focus on having a process of answering the design question.

    Interview Questions

    • HR Phone Screen:
      1. Tell me about yourself.
      2. Why Facebook?
      3. What is a project you've worked on recently?
      4. What's your favorite facebook feature?

      Product Sense Video Interview
      1. Design a way for people to find apartments.

      Product Execution Interview:
      2. How do you deal with trade-offs between opposing metrics, such as higher AoV but lower conversion rate?
      3. For Facebook Groups, how would you increase usage?
      4. For Facebook Marketplace, how would you go about setting the price of the products? What tradeoffs would you make in the options you described in terms of metrics?   Answer Question

  6. Helpful (55)  

    Product Manager Interview

    Anonymous Interview Candidate
    No Offer
    Positive Experience
    Difficult Interview

    Application

    I applied through a recruiter. The process took 3 weeks. I interviewed at Facebook in March 2017.

    Interview

    As most others have noted, the interview process is a 30-minute phone screener with a recruiter, then two back-to-back 45-minute video interviews with lead product managers, one on Product Sense and another on Execution, and then onsite interviews. I did not make it past the video interviews.

    For the phone screener, the recruiter is just looking to make sure you've done relevant product management-type work:
    - Tell me about yourself
    - Have you ever worked on a product/feature you worked on from idea to launch?
    - How did you measure success of that product/feature? (provide examples of metrics you looked at)

    My Product Sense interview was with a product lead on Facebook Messenger. He quickly told me that he had already read through my resume and asked if there was anything else unique about me that wasn't on my resume. He then asked me about two of my favorite consumer products to try and suss out any commonalities across the two to determine what characteristics I value in a good product. We then moved onto the meat of the interview, the product sense hypothetical. He presented the following hypothetical: "Design a way for people with similar interests/hobbies to connect".

    I had prepped a structure of walking through the problem, the user, potential solutions, etc, but I struggled with this particular use case. His feedback was that I jumped too quickly into the solution, and that I needed to back up and talk about "pain points" in a bit more depth. Then, he provided feedback that I was getting stuck on pain points and needed to move onto the solution, as we were running out of time. I had 5 minutes at the end to ask him questions.

    My Execution interview was with a product lead on Instagram, working on safety/community. He briefly introduced himself and his role, and asked me to quickly do the same. He the presented the following hypothetical: "Tell me what metrics you would look at as a product manager for Instagram ads".

    We went through multiple follow-ups, asking me to prioritize which of those metrics would be most important, what to consider about how that metric might not tell the whole story, what I would do if I saw a sharp decrease in that metric from one day to the next, how I would rally the team around addressing that problem vs moving on, etc. I had a lot of fun here and thought I did fairly well with this interview, as it more closely reflected what I do in my current role day to day.

    My advice for the Product Sense and Execution video interviews:
    - Figure out how well you're balanced between these two skill sets.
    - If you're unbalanced, like I was, focus on the area where you are weaker
    - Identify a structure to use for either interview. For Product Sense, I would recommend: 1) Clarify the problem, 2) Understand/make assumptions about the user, 3) Identify pain points, 4) Brainstorm solutions, 5) Explain rationale/tradeoffs. For Execution, I would recommend: 1) Identify the proxy metric that most closely reflects the real-world change, 2) Identify related metrics, 3) Refine to reduce chance of "gaming" the metric, 4) Identify what questions you would ask if those metric(s) fell (external factors, internal to Facebook factors, internal to product/feature factors), 5) Explain how you would make tradeoffs to prioritize addressing the issue. There are various books and websites that can lead you through other ways of structuring your answers to these two types of questions. I'd highly recommend writing out a flow chart of your structure that you can refer to during the interview.
    - Practice hypotheticals out loud with a friend. It was extremely helpful to also refine any problems you might have with communicating your ideas. Take the flow chart you created above and refine it by practicing out loud with a friend. I found it helpful to create a sort of mix-and-match flashcards by printing out 6 starts to a question and combining them with ends of a question. I put all of the starts in one bowl and all the ends in another bowl, and had my friend pick from the two bowls at random. Examples:

    Starts:
    1. Tell me your favorite thing about...
    2. Design/re-design...
    3. How would you measure success of...
    4. How would you fix a problem with...

    Ends:
    1. ...a way for people to find apartments/meet people with similar interests/find something to do this weekend
    2. ...X feature of Facebook/Instagram (i.e. Birthdays, Messenger, Saved, Ads, News Feed, Trending, etc)
    3. ...your favorite product

    Ultimately, this interview process does a really good job at sussing out the skills that you've already developed. Prep can take you the last 10%, but if you don't have a firm foundation, it will be fairly difficult to succeed (at least in my experience). Trust your strengths and shore up your weaknesses.

    Interview Questions

    • Design a way for people with similar interests/hobbies to connect.   Answer Question
    • Tell me about your favorite product.   Answer Question
    • Tell me what metrics you would look at as a product manager for Instagram ads.   1 Answer
    • What questions do you have for me?   Answer Question

  7. Helpful (17)  

    Data Engineer Interview

    Anonymous Interview Candidate in Menlo Park, CA
    No Offer
    Positive Experience
    Difficult Interview

    Application

    I applied online. I interviewed at Facebook (Menlo Park, CA) in July 2017.

    Interview

    One phone tech screen which covered both SQL and Python questions. They do the best job I've seen of hosting this tech screen / interview. They use CoderPad, and actually let you run the queries / functions. For SQL they provide a nice schema for you to reference. And for coding (python) they provide basic methods and reference materials for you to review if needed.

    I did very well on the SQL Questions, which are listed below. A plus is talking through what you PLAN to do before you do it:
    - for each store show the % difference in sales between 2014 and 2015
    - % of all customers that have purchases at least 1 product
    - list all the customers that live in a state, ordered by the number of unique products they bought
    - Find the earliest born and last born customers, by gender, who have bought at least 1 product

    I did not quite do as well on the python stuff. I was able to answer all of the python questions, but I received feedback that I should have talked through and thought through all the test cases they provide. So as to ensure you are working around all edge cases before starting to code. I got 3 questions, but forget the 3rd one. They two I remember were:
    - implement count_words(input_str) function which returns number of words from the input string (hint the edge cases they provide means you have to implement it manually)
    - implement count_substr(input_str, sub_str) function which returns the number of times the sub_str occurs in the input_str.

    On site includes 4 interviews. 1 Lunch interview which is focused on team fit, and finding out if you are passionate about the role / company. You'll want to be able to answer questions like:
    - what product would you want to work on, why, what would you do if you worked on that project?

    The other 3 on site interviews are "full stack" they focus on product sense, data modeling, SQL, data visualization, and coding (python.) You can make it into more of a conversation and it's a good thing to ask clarifying questions. You will have to write everything on a white board throughout the conversations, including data models, viz, SQL, and python functions. They will ask you to solve a specific business problem by coming up with a python function.

    From a guy that didn't get the job, it was still a good experience. They do a good job of making into a much more realistic scenario instead of just a "tell me a time when...." type questions. Good luck to you!

    Interview Questions

    • given a list of tuples of movie watched times, find how many unique minutes of the movie did the viewer watch e.g. [(0,15),(10,25)]. The viewer watched 25 minutes of the movie.   Answer Question
  8. Helpful (1)  

    Software Engineer Interview

    Anonymous Interview Candidate
    No Offer
    Neutral Experience
    Easy Interview

    Application

    I applied through a recruiter. The process took 2+ weeks. I interviewed at Facebook.

    Interview

    Screen followed by full day interviews. Expectation is to solve two questions in two coding rounds in about 35 to 40 mins. So, indirect expectation is to mug up/memorize and spit out there. No time for thinking because many people just mug up to crack. I am not a mugger and this is not a place to work if you really care about solving real unseen problems.

    Interview Questions


  9. Helpful (2)  

    Product Manager Interview

    Anonymous Interview Candidate
    No Offer
    Negative Experience
    Difficult Interview

    Application

    I applied online. I interviewed at Facebook.

    Interview

    The interviews are designed to be challenging - you're going to be asked to drill deep in a particular area or change course (depending on whether you have already covered enough ground or if it looks like you're stuck). Definitely look at Glassdoor for representative questions and practice ahead of time. I enjoyed this process. The Product sense and product execution interviewers let me know they would be taking notes and would interrupt me from time to time. That made it easy to take it in my stride.

    It took them over a week to let me know of the outcome since their debrief meetings kept getting postponed. The recruiter kept me informed throughout the process so I was aware of what was going on.

    My sense of the culture from the interviews was, they definitely look for a certain type of attributes in the types of PMs they hire - think fast on your feet, highly articulate and succinct. They certainly screen heavily for those attributes/characteristics. If you can nail that during your interviews, you will do well.

    Interview Questions

    • Execution - FB decided to launch Reactions? How would you measure success? How would you test?

      Prod Sense - Design a social travel product

      Execution - How should FB grow registrations?

      Prod Sense - Pick a product that you like. what do you like about it.   Answer Question

  10.  

    Software Engineer New Grad Interview

    Anonymous Interview Candidate
    No Offer
    Negative Experience
    Easy Interview

    Interview

    I was given two easy algorithm questions. My interviewer told me I had a bug in my solution to the first, but when they pointed out the "bug" it turns out they just didn't know Python very well.

    For the second question, the interviewer acted like they had never seen dynamic programming before. Did not even seem to grasp the concept. It took me under 5 minutes to come up with a solution, but we spent the entire interview with the interviewer asking the same questions about how it would work. Ran out of time and they wouldn't even let me write down my original solution.

    Asked a few questions about what Facebook engineers spend their time doing other than coding. Received nothing but non-answers to all of them.

    Interview Questions

    • Find the length of the longest increasing subarray in a list   Answer Question
    • Find the length of the longest increasing subsequence (with gaps allowed) in a list   1 Answer

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