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Backend Engineer Interview Questions

Review this list of 20 Backend Engineer interview questions and answers verified by hiring managers and candidates.
  • Airbnb logoAsked at Airbnb 
    106 answers
    Video answer for 'Tell me about a time you made a mistake.'
    +95

    "Let me tell you about a time where a website I managed suddenly showed slow performance and the mistake on our side was it was unnoticed until a user reported the issue to management. As a PM for that project, I took full responsibility of the situation and worked with the engineering team to quickly resolve it. This mistake taught me the importance of focusing and monitoring non functional requirements as well in addition to new feature development /adoption where I was mostly spending my time"

    Sreenisha S. - "Let me tell you about a time where a website I managed suddenly showed slow performance and the mistake on our side was it was unnoticed until a user reported the issue to management. As a PM for that project, I took full responsibility of the situation and worked with the engineering team to quickly resolve it. This mistake taught me the importance of focusing and monitoring non functional requirements as well in addition to new feature development /adoption where I was mostly spending my time"See full answer

    Backend Engineer
    Behavioral
    +10 more
  • Amazon logoAsked at Amazon 
    70 answers
    +62

    "I most want to communicate a few principals of conflict resolution that I believe were integral in this situation, which are mutual respect, a results orientation, an unwavering focus on the user. To that end, here’s how I’d like to structure this answer: First, I’ll tell you about the project we were working on, to provide some background for you. Second, I’ll describe the disagreement. Third, I’ll describe how we arrived at a solution, and finally, I’ll discuss how those 3 conflict resolut"

    Ross B. - "I most want to communicate a few principals of conflict resolution that I believe were integral in this situation, which are mutual respect, a results orientation, an unwavering focus on the user. To that end, here’s how I’d like to structure this answer: First, I’ll tell you about the project we were working on, to provide some background for you. Second, I’ll describe the disagreement. Third, I’ll describe how we arrived at a solution, and finally, I’ll discuss how those 3 conflict resolut"See full answer

    Backend Engineer
    Behavioral
    +8 more
  • Accenture logoAsked at Accenture 
    126 answers
    Video answer for 'Tell me about yourself.'
    +118

    "As you know, this is the most important question for any interview. Here is a structure I like to follow, Start with 'I'm currently a SDE/PM/TPM etc with XYZ company.... ' Mention how you got into PM/TPM/SDE field (explaining your journey) Mention 1 or 2 accomplishments Mention what you do outside work (blogging, volunteer etc) Share why are you looking for a new role Ask the interviewer if they have any questions or will like to dive deep into any of your experience"

    Bipin R. - "As you know, this is the most important question for any interview. Here is a structure I like to follow, Start with 'I'm currently a SDE/PM/TPM etc with XYZ company.... ' Mention how you got into PM/TPM/SDE field (explaining your journey) Mention 1 or 2 accomplishments Mention what you do outside work (blogging, volunteer etc) Share why are you looking for a new role Ask the interviewer if they have any questions or will like to dive deep into any of your experience"See full answer

    Backend Engineer
    Behavioral
    +17 more
  • Google logoAsked at Google 
    13 answers
    +9

    "Designing a system to deny services to requests from banned IPs involves integrating real-time IP checking with your service architecture. Here’s a detailed outline of how you can design such a system: System Design Overview The goal is to ensure that your service can efficiently check incoming requests against a list of banned IPs and deny access when necessary. The system will leverage an external API, security.gov.x, to determine if an IP address is blocked or allowed. **Key Compone"

    Palak A. - "Designing a system to deny services to requests from banned IPs involves integrating real-time IP checking with your service architecture. Here’s a detailed outline of how you can design such a system: System Design Overview The goal is to ensure that your service can efficiently check incoming requests against a list of banned IPs and deny access when necessary. The system will leverage an external API, security.gov.x, to determine if an IP address is blocked or allowed. **Key Compone"See full answer

    Backend Engineer
    System Design
    +2 more
  • IBM logoAsked at IBM 
    70 answers
    +64

    "SELECT MIN(id) AS id, TRIM(LOWER(email)) AS cleaned_email FROM users GROUP BY cleaned_email ORDER BY id `"

    Salome L. - "SELECT MIN(id) AS id, TRIM(LOWER(email)) AS cleaned_email FROM users GROUP BY cleaned_email ORDER BY id `"See full answer

    Backend Engineer
    Coding
    +3 more
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  • Adobe logoAsked at Adobe 
    31 answers
    +26

    "We can use dictionary to store cache items so that our read / write operations will be O(1). Each time we read or update an existing record, we have to ensure the item is moved to the back of the cache. This will allow us to evict the first item in the cache whenever the cache is full and we need to add new records also making our eviction O(1) Instead of normal dictionary, we will use ordered dictionary to store cache items. This will allow us to efficiently move items to back of the cache a"

    Alfred O. - "We can use dictionary to store cache items so that our read / write operations will be O(1). Each time we read or update an existing record, we have to ensure the item is moved to the back of the cache. This will allow us to evict the first item in the cache whenever the cache is full and we need to add new records also making our eviction O(1) Instead of normal dictionary, we will use ordered dictionary to store cache items. This will allow us to efficiently move items to back of the cache a"See full answer

    Backend Engineer
    Data Structures & Algorithms
    +6 more
  • Booking.com logoAsked at Booking.com 
    8 answers
    Video answer for 'Design a metrics and logging service.'
    +1

    "For somebody who needs accessibility accommodation, this doesn't have a transcript so it is not useful to me."

    Shivastuti K. - "For somebody who needs accessibility accommodation, this doesn't have a transcript so it is not useful to me."See full answer

    Backend Engineer
    System Design
    +2 more
  • Amazon logoAsked at Amazon 
    7 answers
    +4

    "Authentication verifies "Who you are." Authorization determines "What you can do." Authentication establishes identity, while authorization specifies the actions or resources a user or entity is allowed to access or perform."

    Surbhi A. - "Authentication verifies "Who you are." Authorization determines "What you can do." Authentication establishes identity, while authorization specifies the actions or resources a user or entity is allowed to access or perform."See full answer

    Backend Engineer
    Technical
    +1 more
  • Anthropic logoAsked at Anthropic 
    2 answers
    Video answer for 'Design a key-value store.'

    "Simple file system ( Hash Map , LSM trees), and consistent hashing. I failed to discuss about conflicts ( Versioning)"

    V V. - "Simple file system ( Hash Map , LSM trees), and consistent hashing. I failed to discuss about conflicts ( Versioning)"See full answer

    Backend Engineer
    System Design
    +2 more
  • Paytm logoAsked at Paytm 
    Add answer
    Backend Engineer
    Product Design
    +2 more
  • Amazon logoAsked at Amazon 
    10 answers
    Video answer for 'What is your leadership style?'
    +7

    "My leadership style is flexible and adaptive, it varies depending on the team members and the needs of the company. My leadership goal is to empower the team and inspire and grow leaders. In order to achieve that, I combine transformational, democratic and coaching leadership styles. Usually when we are facing a new type of challenge, or at the early stage of a project, I like to adapt the transformational leadership which allows me to listen to all the suggestions from the team members and sta"

    onering2ruleall - "My leadership style is flexible and adaptive, it varies depending on the team members and the needs of the company. My leadership goal is to empower the team and inspire and grow leaders. In order to achieve that, I combine transformational, democratic and coaching leadership styles. Usually when we are facing a new type of challenge, or at the early stage of a project, I like to adapt the transformational leadership which allows me to listen to all the suggestions from the team members and sta"See full answer

    Backend Engineer
    Behavioral
    +5 more
  • Accenture logoAsked at Accenture 
    16 answers
    +11

    "public static Integer[] findLargest(int[] input, int m) { if(input==null || input.length==0) return null; PriorityQueue minHeap=new PriorityQueue(); for(int i:input) { if(minHeap.size()(int)top){ minHeap.poll(); minHeap.add(i); } } } Integer[] res=minHeap.toArray(new Integer[0]); Arrays.sort(res); return res; }"

    Divya R. - "public static Integer[] findLargest(int[] input, int m) { if(input==null || input.length==0) return null; PriorityQueue minHeap=new PriorityQueue(); for(int i:input) { if(minHeap.size()(int)top){ minHeap.poll(); minHeap.add(i); } } } Integer[] res=minHeap.toArray(new Integer[0]); Arrays.sort(res); return res; }"See full answer

    Backend Engineer
    Data Structures & Algorithms
    +3 more
  • American Express logoAsked at American Express 
    4 answers
    +1

    "After more than five years at my previous company, I had contributed significantly to many important projects and helped the team navigate critical transitions, such as our shift from a monolithic to a microservices architecture. However, over time, I realized that my goals and the direction of the company were no longer fully aligned. I felt I had outgrown the position and was ready for new challenges, where I could continue to grow both technically and professionally. Ultimately, I’m excited a"

    Chinedu ekene O. - "After more than five years at my previous company, I had contributed significantly to many important projects and helped the team navigate critical transitions, such as our shift from a monolithic to a microservices architecture. However, over time, I realized that my goals and the direction of the company were no longer fully aligned. I felt I had outgrown the position and was ready for new challenges, where I could continue to grow both technically and professionally. Ultimately, I’m excited a"See full answer

    Backend Engineer
    Behavioral
    +2 more
  • Airbnb logoAsked at Airbnb 
    1 answer

    "I'm currently a School Bus Monitor at First Student, I make sure that the students on the bus are seated down, making sure they are safe during the bus ride. Sometimes depending on the day they may need me to help do a wheelchair so I sometimes help the driver out with making sure the wheelchair is safely secure, hooking up the 4 hooks on the wheelchair, putting the lap belt on the student and also making sure the student feels comfortable during the bus ride. After we finished dropping off our"

    Amparo L. - "I'm currently a School Bus Monitor at First Student, I make sure that the students on the bus are seated down, making sure they are safe during the bus ride. Sometimes depending on the day they may need me to help do a wheelchair so I sometimes help the driver out with making sure the wheelchair is safely secure, hooking up the 4 hooks on the wheelchair, putting the lap belt on the student and also making sure the student feels comfortable during the bus ride. After we finished dropping off our"See full answer

    Backend Engineer
    Behavioral
    +4 more
  • "solving to find a cycle in directed graph"

    XponentShift32 - "solving to find a cycle in directed graph"See full answer

    Backend Engineer
    Data Structures & Algorithms
    +1 more
  • Walmart Labs logoAsked at Walmart Labs 
    1 answer

    " import java.util.*; enum RideType { SHARED, PRIVATE, EXECUTIVE } enum VehicleType { SEDAN, SUV, HATCHBACK, LUXURY, VAN, ELECTRIC, AUTO_RICKSHAW, BIKE_TAXI } final class Location { private final double logitude; private final double latitude; private final String location; public Location(double logitude, double latitude, String location){ this.logitude = logitude; this.latitude = latitude; this.l"

    Yash G. - " import java.util.*; enum RideType { SHARED, PRIVATE, EXECUTIVE } enum VehicleType { SEDAN, SUV, HATCHBACK, LUXURY, VAN, ELECTRIC, AUTO_RICKSHAW, BIKE_TAXI } final class Location { private final double logitude; private final double latitude; private final String location; public Location(double logitude, double latitude, String location){ this.logitude = logitude; this.latitude = latitude; this.l"See full answer

    Backend Engineer
    System Design
  • Reddit logoAsked at Reddit 
    Add answer
    Backend Engineer
    Behavioral
    +2 more
  • Backend Engineer
    Data Structures & Algorithms
    +1 more
  • Apple logoAsked at Apple 

    Coin Change

    IDE
    Medium
    12 answers
    +9

    "The example given is wrong. The 2nd test case should have answer 3, as we can get to 6 by using 3 coins of denomination 2."

    Anmol R. - "The example given is wrong. The 2nd test case should have answer 3, as we can get to 6 by using 3 coins of denomination 2."See full answer

    Backend Engineer
    Coding
    +4 more
  • Excel Impact logoAsked at Excel Impact 
    2 answers

    "voice"

    Ravi K. - "voice"See full answer

    Backend Engineer
    Product Design
    +3 more
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