MongoDB
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www.mongodb.com New York, NY 150 to 499 Employees

MongoDB Interview Questions & Reviews

Updated Mar 10, 2014

Getting the Interview 

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33%
13%

Interview Experience 

64%
14%
21%

Interview Difficulty 

19 candidate interviews Back to all interview questions
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1 person found this helpful

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Average Interview

Software Engineer Intern Interview

Anonymous Interview Candidate

I applied through a recruiter and the process took 2 weeks - interviewed at MongoDB.

Interview Details – I applied through a recruiter after meeting a MongoDB employee at a hackathon. I went through an informal get to know you interview over the phone and then a technical interview over the phone. Both phone interviewers were extremely kind, and I thought the person conducting the technical interview was both patient and helpful.

Interview Question – First I was asked a few basic design questions, like how I would design an online chat system with separate room. Then I was asked why I've chosen some of of the technologies that I have worked with.I was asked a standard question about manipulating an array. The input array was sorted integers, and I was asked how to square all the elements and keep it sorted.   View Answer

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Average Interview

Software Engineering Internship Interview

Anonymous Interview Candidate

I applied online and the process took 2 weeks - interviewed at MongoDB in October 2013.

Interview Details – I applied online and talked to them at a career fair and they emailed me for a phone interview. I was asked technical questions and we had a brief conversation about mongoDB.

Interview Question – It wasn't super difficult but I was asked to write a prime factorization function:
// print the prime factors of the input number.
void primeFactorsPrint(int num)
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Intern Interview

Intern

I applied through college or university and the process took 2 weeks - interviewed at MongoDB in December 2013.

Interview Details – First, talked to one of the software engineers at my school's career fair, really connected. Got an email from HR in end of November. Few days later, got a call, talked to the HR person for about 15 minutes. Got an email scheduled for a technical (some friends didn't get this) and got a phone call at the scheduled time.

Waited for about 20 minutes for them to call. He had a meeting. He was nice enough. Went over my resume, interests, etc... this part went fine, but by the time we got to the technical question, we barely had any time left.

His question was "Taking in two strings, find out if they are anagrams". I used a hashtable, which takes a lot of memory. The correct answer (or the one he said was an alternative, though mine worked as well) was sorting it first, then comparing them.

And that was that, they sent me a polite rejection email.

Interview Question – His question was "Taking in two strings, find out if they are anagrams".   View Answer

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1 person found this helpful

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Neutral Experience

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Software Engineering Intern Interview

Anonymous Interview Candidate

I applied through a recruiter and the process took 4 weeks - interviewed at MongoDB in November 2013.

Interview Details – Got contacted by MongoDB, since they had my resume from last year. I went through a 45 minute technical interview by phone, then another 45 minute phone interview, and finally three interviews onsite. I felt the onsite interview questions were not that difficult, but I tunnel visioned too hard on one approach and missed an easy solution.

Interview Question – Given a string of parantheses, brackets, and curly braces, write a function that returns whether the string is well balanced, in that every left delimiter is closed by the correct right delimiter. I was asked this question by multiple interviewers, it seems like their go-to question.   View Answer

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Positive Experience

Average Interview

Intern Interview

Intern

I applied online and the process took 2 months - interviewed at MongoDB.

Interview Details – Applied online and heard back a month or two later. First had a phone screen where we discussed my resume and I was told I would have a technical interview. During the technical interview I was asked a couple OOP questions and then asked two coding questions. The first was easier than the second and in the second after I wrote the solution we worked through it to try and reduce the time complexity.

Interview Question – Pretty standard questions, I was asked to rank my relative experience in different languages and then choose one to write in.   Answer Question

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Positive Experience

Average Interview

Intern Interview

Anonymous Interview Candidate

I applied through college or university and the process took 3 weeks - interviewed at MongoDB.

Interview Details – Had an HR Interview where I discussed why I wanted to work with the company, which lasted around 45 minutes.

Then I had a Skype interview with an employee that worked remotely; it was really great talking to him. He was very nice, and I learned a lot from him, though he wasn't able to tell me a lot about the culture at the office since he visited less frequently.

The last part of the process was a phone interview. The person I talked to was a little awkward, but she was very nice and I enjoyed the conversation.

Interview Question – I had a rather lengthy discussion during the Skype interview about how garbage collectors were implemented in various languages. I don't know if I would say it was a question perse, but it was difficult giving adequate explanations of each, discussing not only the implementation but also the pros and cons.

I also had a question about finding the largest prime divisor of a number, which I thought was difficult because the question itself was so easy, so it was kinda difficult to find good ways to optimize.
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Neutral Experience

Intern Interview

Anonymous Interview Candidate

Interviewed at MongoDB

Interview Details – 1 HR telephone interview, 2 technical interviews

Interview Question – algorithms, data structures, projects   Answer Question

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Neutral Experience

Event Coordinator Interview

Anonymous Interview Candidate

Interviewed at MongoDB

Interview Details – Several phone interviews, was invited in and met 6 different people, all went very well. Last interview was with VP. Never heard from them again.

Interview Question – How many gas stations in the United States?   Answer Question

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1 person found this helpful

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Average Interview

Database Kernel Engineer Interview

Anonymous Interview Candidate

I applied online and interviewed at MongoDB.

Interview Details – Applied online and got a call from the recruiter. Had an initial phone screen. I answered all the questions except the C++ ones. I didn't know they were big on C++ knowledge.

Interview Question – The questions on C++ were the unexpected ones. Interviewer asked me to write a very simple coding questions, but asked me to use vectors from the C++ standard library and use iterators for iterating through those elements. I couldn't answer as C++ isn't on my resume.   Answer Question

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1 person found this helpful

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Positive Experience

Difficult Interview

New/Recent Grad - Software Engineering Interview

Anonymous Interview Candidate
New York, NY

I applied online and the process took 2 weeks - interviewed at MongoDB in March 2013.

Interview Details – One phone screen. One technical phone interview coding on google docs. How would you write DB write / access functions to make sure data is not modified by threads. Parse mathematical expression given as chars in array ['1', '+', '2,' '/', '4']. Four onsite interviews over the course of 4 hours asking a variety of questions. Write algorithm to find loop in graph, write C code to convert integer to string.

Interview Question – Write an algorithm to find a loop in a graph. The graph is unidirectional with any number of connections. The graph is not necessarily connected   View Answers (2)

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