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Scalable System Design Interview Questions

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Design An Events Website

System Design Interview: “What is a Scalable System?”

Q. Imagine you are a founder of a website that wants to sell tickets for events online. Discuss a plan for releasing a minimum viable product website for this startup and define an architecture to support the requirements.

The following is a representation of a real-life Full Stack System Design interview setting involving a technical architect/staff engineer. Weâve listed examples of follow-up questions to the question listed above and ideal answers for each.

This interview is purely fictitious, and any resemblance to a real-life setting is coincidental.

How To Design Instagram Best Way To Answer This System Design Interview Question

As you may know, Instagram is a photo-sharing app through which users can upload and share their photos and videos with other users. For cracking system design interview questions like âDesign Instagram,â you can focus on designing a simpler app version.

On their timeline, the user can share photos, follow other users, and get a news feed of top images from other people they follow. The answer will not address commenting on photos, tagging users, or sharing the pictures to other social networking platforms like Facebook or Flickr.

What Are The Advantages And Disadvantages Of Horizontal Scaling

From a hardware standpoint, scaling is simpler: all you have to do is add more machines to your current pool to scale horizontally. It removes the requirement to figure out which system specifications need to be upgraded. Increased fault tolerance and resilience – Relying on a single node for all of your data and processes puts you at danger of losing everything if it goes down. You can avoid losing it entirely by distributing it over multiple nodes.

Increased performance – When you use horizontal scaling to manage your network traffic, you may connect more endpoints because the load is distributed over numerous workstations.

Disadvantages of horizontal scaling:

Increased maintenance and operation complexity Maintaining several servers is more difficult than maintaining a single server. You’ll also need load balancing software and maybe virtualization software. It’s also possible that backing up your equipment will become more difficult. You’ll need to make sure the nodes are synchronised and communicating properly.

Initial costs are higher – Adding new servers is far more expensive than upgrading existing ones.

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Bloomberg Software Engineer Interview Questions

If youâre a software engineer getting ready for the Bloomberg technical interview, you can typically expect questions around coding, systems design, and behavioral psychology. Even if youâre applying to roles like Machine Learning, Cloud Computing, Data Engineering, or DevOps, youâll still have to demonstrate excellent problem-solving skills through your ability to solve tough coding problems. You would also need to exhibit the ability to build scalable systems and applications.

Letâs look at some Bloomberg interview questions for software engineers on coding, systems design, and behavioral psychology.

System Design Interview Questions Pattern


System design interview consists of open-ended processes facilitating a creative discussion between the candidate and the interviewer. Consequently, there are no ready answers to be followed during System Design Interview. However, a typical system design question ends in designing a system based on the problem. Therefore, we have created a standard answer framework to crack each question in a systematic way.

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What Is Included In The System Design Document

The System Design Document describes the systems design details and the interaction of each system component with other components. It also describes the interaction of system components with external systems and the interface, which enables users to perform a task using the system. It also covers the input format, output layouts, processing logic, and different interfaces The document records the results arrived at during the design process. It also describes how the system will fulfill requirements.

How Would You Design A Tinyurl System

A tinyURL is an URL service that allows users to enter a long URL, and then it returns a shorter, unique URL. A hiring manager might ask this to allow you the opportunity to show your solid foundation in design. You can focus on other basics not listed in the example response, like how you create a unique ID for each URL, how you handle redirects and how you delete expired URLs.

Example:”When I was working for a public instant messaging site, I was charged with creating a simple system where every message was limited to 140 characters. It also necessitated shortened URLs of about 30 characters. This tinyURL system is also useful when entering hyperlinks in e-mails or on a smartphone, where there is room for error. TinyURL is a perfect example of the hashtag table. This data structure associates keys with values and is a simple connections code. By using this basic 16-bit hash table, I was able to optimize usability and meet the needs of the system.”

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Ii: Establish The Scope Of Api

The next step to answer the system design interview question is to outline the endpoints for the API design. Youâll need to include the following:

  • followUser
  • unfollowUser

SOAP, REST APIs, or Graph APIs are useful APIs you can use to answer this. Remember that your interviewer is interested to know how you will be handling scrolling and pagination. Hereâs a list of APIs used for managing the backend of Twitter:

  • Login API- Post API to authenticate the user.
  • Signup API- Post API to create a user.
  • Get all Tweets- Get API /api/users/$/tweets?page=1& size=30
  • Create a tweet- Post API /api/users/$/tweets
  • Get all followers- Get API /api/users/$/followers?page=1& size=30
  • Get all following- Get API api/users/$/followers?page=1& size=30

For the front-end systems design interview questions, you will need to talk about React, Redux, and reverse proxy and touch upon issues like notification and offline browsing. Next, you can start sketching out the architecture that will support the various features. You can begin with the user who makes a request to the server.

Tips To Crack Amazon System Design Interview Questions

Amazon System Design Preparation (SIP)

As you may have noticed, the Amazon system design interview questions can be tricky. The questions are ambiguous, and you will have to deal with the unstructured nature of the discussion. However, with extra practice, youâll be prepared to handle anything the interviewers throw at you. Hereâs what you should do before and during the interview to make the best impression.

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Are System Design Interviews Difficult

System design interview questions are notoriously difficult to prepare for. Unlike algorithmic questions, they don’t reduce down to a handful of prescribed patterns. Instead, they require years of technical knowledge and experience to answer well.

For junior engineers, this can be tricky. Even senior developers sometimes find themselves scratching their head trying to understand a system.

The key to doing well in these types of interviews is to use your entire knowledge-base to think about scalability and reliability in your answer.

Section : System Availability

Software engineers aim to build systems that are reliable. A reliable system is one that consistently satisfies a user’s needs, whenever that user seeks to have that need satisfied. A key component of that reliability is Availability.

It’s helpful to think of availability as the resiliency of a system. If a system is robust enough to handle failures in the network, database, servers etc, then it can generally be considered to be a fault-tolerant system – which makes it an available system.

Of course, a system is a sum of its parts in many senses, and each part needs to be highly available if availability is relevant to the end user experience of the site or app.

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The Article Consists Of 3 Parts A Preparation Guide A System Design Template And Design Questions With Links

For my system design interview with Amazon, I watched video lectures, read blog posts, and discussed with my friends’ various approaches to designing a system. After my extensive preparation, I came up with a template that I followed during my interview and wanted to share and hope it would help anyone preparing for a system design interview.

Other Than Block Storage Explain Two Other Storage Techniques Designers Consider In System Design

Scalability 101
  • File storage

File storage refers to a hierarchical storage mechanism. With this methodology, information is saved in files that are stored in folders, which are then housed in directories. Only a small quantity of data, especially structured data, may be stored using this approach.

  • Object storage

This is a type of storage technique for handling large amounts of unstructured data. Due to its dynamic scalability, object storage is the ideal form of data storage for data backups and archiving. An operating system cannot directly access object storage.

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Design Facebooks Newsfeed System

Facebooks newsfeed allows users to see what is happening in their friend’s circle, liked pages and groups followed.

  • What are some of the Required Features?
  • Generate newsfeed using posts from other system entities that the user follows.
  • Newsfeed posts can be of text, image, audio or video format.
  • Append new posts to the users newsfeed in close to real-time.
  • What are some of the Common Problems encountered?
  • What happens if the new post sees a lot of latency to get appended to the news feed?
  • Can the algorithm handle sudden user load?
  • What posts should take priority for displaying in the news feed?
  • Possible tips for consideration:
  • Evaluate the process of fanout for publishing posts to the followers
  • Check how sharding can be achieved efficiently for handling heavy user load. The feed data of a user shouldn’t be put into multiple servers. Instead, sharding can be done on user ids.
  • Briefly Explain What Microservices Mean

    These constitute an architectural style, which uses loosely coupled services to structure an application.

    It separates a big application into a bunch of independent, modular services. These modules can be created, used, and maintained separately. Traditional monolithic apps cant keep up with the pace and reliability of microservices. Each independent service in the program has its own codebase and logic since the application is divided into separate services. Application Programming Interfaces allow these services to communicate with one another. If a system designer wants to create a more scalable application, microservices are perfect for that. Because of its cutting-edge features and modules, microservices make it considerably simpler to scale applications.

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    What Are The Major Components Used In Designing A Web Crawler

    The primary function of a web crawler is to enhance Google search results by crawling and indexing page links. Storage systems and APIs are mandatory components of designing a web crawler. Also, we have to assess various things: how to find new web pages and how to prioritise web pages. Check this video link to get details.

    How Are Performance And Scalability Related To Each Other

    Understand Scalability In System Design Interview | System Design Preparation

    The ability to handle a large amount of traffic in any application is referred to as scalability, whereas performance is about testing the speed with which the application is running. The increased performance is directly proportional to the number of resources added to the system. The ability to handle larger data sets in the event of growing work makes scalability directly related to the performance of any design. Performance problems might affect just one user, whereas the system might eventually become slow in case of scalability issues due to heavy data load.

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    How Do You Design A Url Shortening Service Like Tinyurl Or Bitly

    TinyURL or takes a long URL and generates a new unique short URL. These systems are also capable of taking the shortened URL and returning the original full URL.

    • What are some of the Required Features?
    • Generate a short URL having a length shorter than the original URL.
    • Store the original URL and map it to the shortened one.
    • Allow redirects in the shortened URLs.
    • Support custom names for short URLs.
    • Handle multiple requests at the same time.
  • What are some of the Common Problems encountered?
  • What if two users input the same custom URL?
  • What happens if there are more user load than expected?
  • How do you regulate the database storage space?
  • Possible tips for consideration:
  • The concept of hashing can be used for linking original and new URLs.
  • REST API can be used for balancing high traffic and handling front-end communication.
  • Multithreading concept for handling multiple requests at the same time.
  • NoSQL databases for storing original URLs.
  • What Is A Load Balancer

    A load balancer distributes network traffic across a cluster of servers. This ensures that no single server is over-loaded hence improving the responsiveness of an application, and also improving the availability of the application.

    In a distributed application multiple load balancers are commonly put between different layers – Between the client and web serversBetween the web servers and application serversBetween the application servers and database servers.

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    What Are Different Kinds Of Data Replication

    There are two kinds of data replication.

    Master-slave replication – In this kind of replication the master serves both read and write requests, and replicates the writes to one or more slaves. The slaves serve read requests only. If the master goes down, the system will continue to serve in read-only mode until the system promotes a slave to a master, or until a new master is provisioned.

    Master-master replication – In this kind of replication multiple masters serve read and write requests. The writes are replicates to all master servers. The masters are fronted with a load balancer, and even if a master goes down the system will continue to serve read and write requests from the other masters.

    Data Partitioning

    Following are some frequently asked questions in Data Partitioning

    System Design Interview Questions Concepts You Should Know


    You may have heard the terms “Architecture” or “System Design.” These come up a lot during developer job interviews especially at big tech companies.

    This in-depth guide will help prepare you for the System Design interview, by teaching you basic software architecture concepts.

    This is not an exhaustive treatment, since System Design is a vast topic. But if you’re a junior or mid-level developer, this should give you a strong foundation.

    From there, you can dig deeper with other resources. I’ve listed some of my favourite resources at the very bottom of this article.

    I’ve broken this guide into bite-sized chunks by topic and so I recommend you bookmark it. I’ve found spaced learning and repetition to be incredibly valuable tools to learn and retain information. And I’ve designed this guide to be chunked down into pieces that are easy to do spaced repetition with.

    Let’s get started!

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    What Are System Design Interviews

    System design interviews typically test the knowledge and design skills of professionals seeking an upper-level position in a technological field. In system design interviews, applicants answer broad questions by developing a prototype system using key components to outline a model before explaining their approach. Interviewers may also ask job candidates questions to determine their technical knowledge and experience. They are commonly used for roles like development manager, system engineer or technical program manager.

    Bloomberg Interview Questions On Coding

    Coding forms the fundamental part of the Bloomberg software engineering interview. It also forms the basis of interviews for Machine Learning, Data Engineering, Application Development , cloud engineering, and web developer positions.

    To solve Bloomberg interview questions on coding, you should be adept with the following topics –

    • Graph algorithms, including greedy algorithms

    Here are some sample Bloomberg interview questions on coding:

  • If a rotationally sorted array is given, write a program code that finds a particular element.
  • Write a code to check whether a binary tree is a valid binary search tree.
  • Write a program that determines if the permutation of a string is a palindrome or not.
  • Write a program that can check if a given binary tree is balanced or not
  • You are given a string in a certain format of words. Create a program that will output the string characters in reverse.
  • Determine whether any two integers added together equal a given value.
  • The following input contains a two-dimensional array with all the elements of the array as unique positive integers. You should write a java program that will find all the arrays that do not have any element as zero.
  • You are given two linked lists. List A has integer values, and List B has integer values. Write a program that adds the two linked lists and returns their sum.
  • You’re given the information to find the values at every level of a binary tree. Write a code that can do so.
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    List Of Common System Design Interview Questions

    • Design a global chat service like Facebook Messenger or WhatsApp
    • Design a social network and message board service like Quora or Reddit
    • Design a global file storage and sharing service like Dropbox or Google Drive
    • Design a global video streaming service like YouTube or Netflix
    • Design an API rate limiter for sites like Firebase or GitHub
    • Design a proximity server like Yelp or Nearby Places/Friends
    • Design a search engine related service like Type-Ahead
    • Design Ticketmaster
    • Design Twitter
    • Design a Web Crawler

    To learn how to solve these System Design Interview problems along with all of the System Design fundamentals, I recommend Scalability & System Design for Developers.

    Google Systems Design Interview Process

    Scalability | System Design Interview Basics 2022

    The systems design interview round happens after the technical phone screen interview. You wonât be asked any design questions during your phone screen interview, as the initial phone screen mainly focuses on coding questions around data structures and algorithms.

    The design interview happens much later in the interview process, during the on-site or in-person interview. After passing the phone screen round, youâre invited to Googleâs campus for on-site technical and behavioral interviews.

    To understand more about Googleâs interview process,

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