System Design Interview: Doordash
In this course, youll use DoorDash as a case study. It will familiarize you with encounters you can expect at the interview.
First youll learn to understand the theory behind system design interviews. Then youll learn how to:
identify a systems requirements
handle data
lay down architecture of the system
And beyond.
Educative.io
Youll work with diagrams and quizzes to help you understand concepts.
By the end of System Design Interview: DoorDash, youll know how to confidently approach a system design interview.
SystemsExpert is designed to help you ace the FAANG-level system design interview.
This is brought to you by the creators of AlgoExpert.
So after learning system design fundamentals, youll work on 10 questions asked at actual FAANG interviews.
Video accompanies each problem with a mock-interview scenario. These help you understand what clarifying questions you should be asking at a system design interview.
And the 4-pane integrated workspace shows you the prompt, scratchpad, video solution and the solution walkthrough.
Youll get a certificate of completion at the end of the course.
Use promo code realtoughcandy and save 10%
A Encoding Actual Url
We can compute a unique hash of the given URL. The hash can then beencoded for displaying. This encoding could be base36 or base62 and ifwe add – and . we can use base64 encoding. A reasonable question would be, what should be thelength of the short key? 6, 8 or 10 characters.
Using base64 encoding, a 6 letter long key would result in 64^6 = ~68 billion possible stringsUsing base64 encoding, an 8 letter long key would result in 64^8 = ~281 trillion possible strings
With 68 unique strings, lets assume six letter keys would suffice for our system.
If we use the MD5 algorithm as our hash function, itll produce a 128-bit hash value. After baseencoding, well get a string having more than 21 characters . Since we only have space for 8 characters per short key, how will we choose our keythen? We can take the first 6 letters for the key. This could result in key duplication though, uponwhich we can choose some other characters out of the encoding string or swap some characters.
What are different issues with our solution? We have the following couple of problems with ourencoding scheme:
KGS also has to make sure not to give the same key to multiple servers. For that, it must synchronize the data structure holding the keys before removing keys from it and giving them to aserver
6 * 68 = 412 GB.
High level system design for URL shortening
Review Of Grokking The System Design Interview Course
Grokking the System Design Interview is an online course developed by Design Gurus. According to its authors, this course has helped more than 60 thousand people to prepare for their System Design Interviews.
System design questions have become a standard part of the software engineering interview process. Companies like Google, , or Amazon put a special focus on system design interviews . If you want to get a reasonable offer, you need to prove your knowledge of designing complex systems.
Most engineers struggle with system design interviews, mainly due to the open-ended nature of design problems that dont have a standard answer. Like coding interviews, candidates who havent put a deliberate effort to prepare for SDIs, mostly perform poorly, especially at top companies like Google, Facebook, Amazon, Microsoft, etc. In these companies, candidates who do not perform above average have a limited chance to get an offer. On the other hand, a good performance always results in a better offer since it shows the candidates ability to handle a complex system.
In this post, I will present a candid review of one of the most famous resources that many people have used to prepare for their system design interview: Grokking the System Design Interview.
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Depth Of System Design Interview Question
The course did a reasonable job of going deep into the architecture of each problem. Although it would be sufficient for most engineers, some senior engineers might feel that they need more details. For SDIs, one crucial thing is to know the tradeoffs between different design decisions. For example, you need to know, which data partitioning scheme best fits your system, or at which layer you can introduce a cache to speed things up. Discussing these options during the interview is the most important aspect interviewers are looking for in a candidate. Grokking the System Design did an excellent job in discussing the tradeoffs between different designs.
S How I Approach The System Design Questions In Interviews

These are the steps I go through mentally in the interviews, followed by actual interview experiences:
- a) Be absolutely sure you understand the problem being asked, clarify on the onset rather than assuming anything
- b) Use-cases. This is critical, you MUST know what is the system going to be used for, what is the scale it is going to be used for. Also, constraints like requests per second, requests types, data written per second, data read per second.
- c) Solve the problem for a very small set, say, 100 users. This will broadly help you figure out the data structures, components, abstract design of the overall model.
- d) Write down the various components figured out so far and how will they interact with each other.
- e) As a rule of thumb remember at least these :
- processing and servers
It generally depends what you are and you will be working on. Also what your level is but these are some of the more frequent interview questions.
- Design amazon’s frequently viewed product page
- Design an online poker game for multiplayer. Solve for persistence, concurrency, scale. Draw the ER diagram for this
- Search engine : basic crawling, collection, hashing etc. Depends on your expertise on this topic
- Design a picture sharing website. How will you store thumbnails, photos? Usage of CDNS? caching at various layers etc.
- Design a news feed : news feed
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Who Are The Authors Of This Course
This course was developed by Design Gurus, a group of senior engineers and hiring managers whove been working at Facebook, Google, Amazon, and Microsoft. The authors of this course have a lot of experience in conducting SDIs and know exactly what is being asked at these interviews. Other courses developed by the same team can be found on their website.
Lets evaluate different aspects of this course.
Grokking The System Design Interview A Step By Step Guide To Master The System Design Interview Pdf Free
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Grokking System Design Interview Course
- Category: System Design
The Grokking System Design course for Interview is a comprehensive guide to mastering IDEs. They have carefully chosen a set of questions that have been repeatedly asked by leading companies and an added bonus is that they also provide comprehensive expertise in handling any system design issues.
Who Wrote The Course
System design has always been a core focus for Educatives team thats because our co-founders helped build pioneering distributed systems at companies like Microsoft and Facebook. Understanding that system design would continue to be a crucial skill in a future increasingly built with distributed systems, our co-founders personally teamed with industry pros and our expert technical content team to create our most comprehensive system design course yet.
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A Few Years Ago A New Online Learning Platform Named Educativeio Wanted To Know If Id Like To Produce A Course For Them
Although I kindly declined , I was intrigued by the platform.
Why?
Well, for one, the course selection on Educative.io is not only robust but wonderfully specific.
For example, Reintroducing React: V16 and Beyond was created for web developers who dabbled in React a year or two ago, but need a modern refresher.
Ruby Concurrency for Senior Engineering Interviews? You dont get more specific than that.
Similarly, theGrokking the System Design Interview course on Educative.io is designed for those who need brushing up on a highly specific skill set: the system design process.
And it was created by hiring managers at Google, Facebook, Microsoft, and Amazon.
That means this course contains actual Google system design interview questions, for example.
So if youre hoping to land a job at one of the FAANGs , read on.
Grokking The System Design Interview
System Design interviews are arguably some of the most difficult for software engineers.
Making it even more challenging, many college computer science courses and coding bootcamps dont include system design in the curriculum.
But Grokking the System Design Interview bridges that gap.
Its designed to expose you to the most important elements of system design asked in FAANG-level interviews.
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Requirements And Goals Of The System
You should always clarify requirements at the beginning of the interview. Be sure to askquestions to find the exact scope of the system that the interviewer has in mind.
Our URL shortening system should meet the following requirements:
Functional Requirements:
Non-Functional Requirements:
Extended Requirements:
Grokking The System Design Interview: Cost

Educative.io offers a few different pricing options.
The first main option is a subscription. You can choose a monthly, yearly, or two-year service. This gives you access to all of Educative.ios courses.
Subscription prices range from about $15 a month up to $60 per month.
Keep in mind, the annual plans are billed yearly.
Alternatively, Educative.io also sells their courses individually.
If you choose that option, Grokking the System Design costs around $80. Keep in mind this is for yearly access to the course.
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Grokking The System Design Interview Features 15 System Design Interview Challenges
Youll learn how to design everything from Dropbox, to Pastebin, to your expected regulars like , and Netflix.
This course was developed by Design Gurus, a group of hiring managers whove been working at Google, Facebook, Amazon and Microsoft.
So the designers of this course know exactly whats being asked at these interviews.
Essentially, Grokking the System Design Interview is a short, concise and practical course broken down into two sections.
System design tools include 2 coding playgrounds, 22 code snippets and over 100 illustrations to reinforce critical concepts.
Want to give Grokking the System Design Interview a shot?
I Personally Think The Yearly Educativeio Subscription Is The Way To Go
That way, you can feast on this course and hundreds of others. Its also part of a learning path called Ace the Java Coding Interview, which consists of 8 other courses in addition to this one.
In my opinion, you cant go wrong with the subscription even if you just need to prepare for a technical interview.
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Mastering The System Design Interview By Frank Kane
- How to choose appropriate algorithms and data structures for system designs
- How to apply horizontal scaling to transactions, data storage, analytics, and databases
- How to structure your interview responses to ensure the best outcomes
- How to approach system design problems from the right angles, and with the right questions.
- How to address the soft skills your interviewer is secretly evaluating you on
- How to work with Big Data, Apache Spark, and Cloud computing.
Here is the link to join this best System Design Interview course Mastering the System Design Interview
A Framework For The Systems Design Interview
System design interviews can feel intimidating, and having a framework on how to navigate them can help you feel more in control. The book recommends a 4-step process that I also agree with:
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What Does The Course Content Cover
This course has 175 lessons, 135 quizzes, 5 playgrounds, and a whopping 828 illustrations. The introduction provides a nice overview of the course, as well as some key features, but you can get an even more detailed look by visiting any of the publicly available introductory modules of this course.If you want a taste, check out:
Each design problem is divided into three stages:
Requirements: Establish the requirements you need to understand before designing the application
Design: Craft a design that fulfills the requirements established above
Evaluation: Check to see if your design meets non-functional requirements, is performance, consistent, available, and scalable
This course is designed to prepare you for the real world, and as such, it concludes with a section on spectacular failures where small mistakes brought down large, successful applications. Here, you can get an under-the-hood analysis of system failures. It analyzes real-life disasters, such as the routine system maintenance that took down Facebook, Instagram, WhatsApp, and Oculus in 2021, and cost companies millions of dollars in revenue loss .
Note: The course is recommended for beginners, but we advise that you familiarize yourself with the fundamental concepts of a distributed system before starting this course. Brushing up on computer networking and operating systems will also be helpful.
Solution Of Frequently Asked System Design Questions
- Designing a URL Shortening service like TinyURL, bit.ly etc
- Designing Pastebin
- Designing Instagram
- Designing Dropbox
- Designing an API Rate Limiter
- Designing Twitter Search
- Designing Yelp or Nearby Friends
- Designing Uber backend
- Designing Ticketmaster
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System Design Interviews: A Step By Step Guide
A lot of software engineers struggle with system design interviews primarily because of threereasons:
- The unstructured nature of SDIs, where they are asked to work on an open-ended design problem that doesnt have a standard answer.
- Their lack of experience in developing large scale systems.
- They did not prepare for SDIs.
Like coding interviews, candidates who havent put a conscious effort to prepare for SDIs, mostlyperform poorly especially at top companies like Google, Facebook, Amazon, Microsoft, etc. In thesecompanies, candidates who dont perform above average, have a limited chance to get an offer. On theother hand, a good performance always results in a better offer , since itshows the candidates ability to handle a complex system.
In this course, well follow a step by step approach to solve multiple design problems. First, lets gothrough these steps:
Why Do We Need Url Shortening

URL shortening is used to create shorter aliases for long URLs. We call these shortened aliases shortlinks. Users are redirected to the original URL when they hit these short links. Short links save a lot ofspace when displayed, printed, messaged, or tweeted. Additionally, users are less likely to mistypeshorter URLs.
For example, if we shorten this page through TinyURL:
educative/collection/page/5668639101419520/5649050225344512/916475904/
tinyurl/jlg8zpc
The shortened URL is nearly one-third the size of the actual URL.
URL shortening is used for optimizing links across devices, tracking individual links to analyzeaudience and campaign performance, and hiding affiliated original URLs.
If you havent used tinyurl before, please try creating a new shortened URL and spend some timegoing through the various options their service offers. This will help you a lot in understanding thischapter.
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Some Advantages Of This Course Are:
Covers dozens of popular designs.Includes a step-by-step explanation of basic, intermediate and advanced concepts.Includes more than 100 illustrations to complement the questions.One downside of the course is that Design challenges are arranged randomly and no specific ranking method is used.
Grokking the System Design Interview is a short, practical and concise course that has been divided into two sections. System design tools include 22 code snippets, 2 coding play areas, and more than 100 illustrations that help reinforce critical concepts.
In general, the course is good if your goal is to become familiar with the different types of systems design questions that are asked during the interview. So, I would say that the course is worth buying but it would have been better if the questions were updated according to the times.
If you feel that you need information not only regarding the questions that may or may not be asked during the interview, but also some real guidance from the mentors who are still working at FAANG and information about the course supplemented with different assignments, I suggest you opt for Advanced Problem Solving Using Systems Design course offered by Tutort Academy.
When you visit the website, an expert gives you a profile review and then connects directly with a mentor who will guide you through the course if it fits your requirements.
All the best and remember to do your own research by visiting the official websites too!
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