Ankit Singh

One of the most common queries I receive is where to prepare for LLD. My answer to that is a bit surprising but I strongly feel it would definitely work. None of the material out there for LLD is useful for interviews and you read that right! Most of the material consists of repositories with a lot of files and a bunch of business logic, which is good for nothing in interviews. LLD interviews basically have four patterns. Pattern 1: Just discuss the class objects with multiple attributes and then discuss a high level interface and write the pseudocode. Pattern 2: Discuss the classes and attributes but this time write executable code with a simple high level interface and its implementation. Pattern 3: This is the most important pattern, where you need to handle concurrency in a multithreaded environment and write executable code. Of course here as well you need to define proper classes and interfaces. Pattern 4: This is very rare and is what you see in most courses. Sometimes this is called machine coding where you are given either an assignment or asked to change existing code or write a repository from scratch. This is mostly asked by early stage or established startups with 2 hr round but is very rare in MNCs. You can see that the common thing among all these patterns is having a proper class design and defining a good workflow (a good interface) for how the system is going to work. One more important thing that really matters is whether your code is extensible for future use cases or not. These aspects don’t need to be learned from courses because you can do it yourself. Pick up a problem, start defining your attributes, check if you can use threads and make it multithreaded or not, and verify whether it is extensible for future cases or not (defining a proper interface will definitely ensure extensibility). That’s all is what you need to do! Unlike DSA or HLD, LLD doesn’t have any proper standard questions. You can get any question on the fly and all you need is proper knowledge of using threads, defining proper attributes, and if possible using some good collections(to code faster in interviews). Looking into courses will take you nowhere because you have to train your brain to solve problems. Hence what I suggest is to pick up a problem, code the solution (I strongly suggest one interface and two or three classes), keep it simple and ask either ChatGPT or Gemini AI to review it and check how you can handle multithreading. Checking external courses will take you nowhere because it’s you who has to think of a solution and no problem statement in LLD is truly unique. One more thing is these courses show you something that you can never practically code in an hour! And ofcourse you don’t need to code that much in an LLD round! This is the experience I gained from giving 20+ LLD interviews but let me know in case you can add up something to this!

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Hi there 👋 As we grow in our careers, our work starts revolving more around design decisions, not just writing code.   And interviews reflect that shift too. From my recent SDE-2 and SSE interviews, here’s the usual pattern  🔹 1–2 rounds on DSA / problem-solving 🔹 1 round on Low-Level Design (LLD)  🔹 1 round on High-Level Design (HLD) Many hiring managers even ask HLD questions based on your real-world projects, not just textbook systems. When it comes to HLD prep, the amount of content can be overwhelming.   If you’re starting out, I’d recommend:   HelloInterview , Alex Xu’s System Design series , YouTube mock interviews — super helpful for learning how to explain clearly under time pressure One of my juniors recently asked - “Why do companies still ask DSA?” Simple - DSA tests your problem-solving mindset.   It’s not about memorizing patterns but showing how you think.   Even 30 - 45 minutes of daily consistency goes a long way. 🔹 In short:  DSA → builds problem solving skills  LLD → reflects code level thinking  HLD → shows system level design     All three matter, just at different depths as you grow. #CareerGrowth #SoftwareEngineering #InterviewPreparation #SystemDesign #DSA

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Confluent offers 40+ LPA fixed and 60+ LPA CTC for engineers with 1+ year of experience — and the interview process Looks similar to this. 𝗥𝗼𝘂𝗻𝗱 1 – 𝗗𝗲𝘀𝗶𝗴𝗻 𝗣𝗿𝗼𝗯𝗹𝗲𝗺 (𝗛𝗮𝘀𝗵𝗠𝗮𝗽 𝗟𝗼𝗴𝗶𝗰) The first round focused on designing a system that efficiently used HashMaps. It tested not only understanding of the data structure but also the ability to think in terms of scalability and performance. 𝗥𝗼𝘂𝗻𝗱 2 – 𝗗𝗦𝗔 (𝗦𝘂𝗱𝗼𝗸𝘂 𝗦𝗼𝗹𝘃𝗲𝗿) A classic backtracking problem, requiring recursive logic and careful handling of constraints. This round tested depth in algorithms and clean code structure. 𝗥𝗼𝘂𝗻𝗱 3 – 𝗗𝗲𝘀𝗶𝗴𝗻 + 𝗣𝗿𝗼𝗯𝗹𝗲𝗺-𝗦𝗼𝗹𝘃𝗶𝗻𝗴 Another design problem involving HashMap-based logic, but simpler in flow. It checked consistency in approach and clarity of thought under time pressure. 𝗥𝗼𝘂𝗻𝗱 4 – 𝗛𝗥 & 𝗕𝗲𝗵𝗮𝘃𝗶𝗼𝗿𝗮𝗹 𝗥𝗼𝘂𝗻𝗱 This round focused on personality, mindset, and motivation. Questions around past failures and comebacks, strengths and weaknesses, and interest in Confluent’s tech stack were asked. It ended with a discussion on career goals, team culture, and a chance to ask questions back to the interviewer. At Confluent, cracking the interview isn’t just about solving problems — it’s about 𝘁𝗵𝗶𝗻𝗸𝗶𝗻𝗴 𝗹𝗶𝗸𝗲 𝗮 𝗯𝘂𝗶𝗹𝗱𝗲𝗿, 𝗰𝗼𝗺𝗺𝘂𝗻𝗶𝗰𝗮𝘁𝗶𝗻𝗴 𝗹𝗶𝗸𝗲 𝗮 𝗽𝗿𝗼𝗳𝗲𝘀𝘀𝗶𝗼𝗻𝗮𝗹, and 𝗮𝗹𝗶𝗴𝗻𝗶𝗻𝗴 𝘆𝗼𝘂𝗿 𝗺𝗶𝗻𝗱𝘀𝗲𝘁 𝘄𝗶𝘁𝗵 𝗽𝗿𝗼𝗱𝘂𝗰𝘁-𝗱𝗿𝗶𝘃𝗲𝗻 𝗲𝗻𝗴𝗶𝗻𝗲𝗲𝗿𝗶𝗻𝗴.

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Most Asked LLD Question in Big Tech Interviews — Using Abstract Factory Pattern 🧩 Question: Design a cross-platform UI toolkit that supports multiple operating systems like Windows, macOS, and Linux. Each OS should have its own version of UI components like Button, Checkbox, and Textbox, but the client code should work seamlessly across all platforms. 🔍 What’s Expected? You’ll need to:  • Provide a clean, scalable architecture for platform-specific UI.  • Ensure the client code doesn’t need to know what platform it’s running on.  • Make it super easy to add new platforms in the future. 🏭 Where Abstract Factory Comes In The Abstract Factory Pattern is perfect here. It helps you create families of related objects (UI elements) without specifying their concrete classes. Think of it like a UI factory for every OS. 🛠️ Core Components  1. Abstract Product Interfaces   • Button, Checkbox, Textbox — define behavior, not the looks.  2. Concrete Products   • WindowsButton, MacButton, LinuxButton, etc. — actual UI for each OS.  3. Abstract Factory Interface   • UIFactory — declares methods like createButton(), createCheckbox().  4. Concrete Factories   • WindowsUIFactory, MacUIFactory, LinuxUIFactory — platform-specific builders.  5. Client Code   • Uses the UIFactory interface to create elements, but doesn't care about the OS. Real World Usage This is how Flutter, Qt, or even Java Swing/AWT handle cross-platform components internally. Abstract Factory keeps the platform code abstracted and the UI logic reusable. 🔁 Extendability Need to support Android or iOS later? Just create AndroidUIFactory or iOSUIFactory. No need to touch your client code. That’s the power of Abstract Factory 🔥 ✅ Benefits  • High scalability  • Decouples platform logic  • Easy to maintain and test If your LLD interviewer gives you a “platform-based” or “theme-based” system to design (e.g., dark vs light theme, different regions, etc.), always think Abstract Factory. Follow 🤝 : Prateek Goel #systemdesign #lld #abstractfactory #designpatterns #bigtechinterviews #java #designthinking

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I have researched lots of product-based companies like Amazon, Stripe, Netflix, Asana, Zomato, Goldman Sachs, Paytm, Reddit, Inc., etc. for SDE-1 and SDE-2 roles, and found that variations of these frontend system design questions show up repeatedly in interviews. 𝐅𝐫𝐞𝐬𝐡𝐞𝐫 𝐋𝐞𝐯𝐞𝐥 𝐒𝐲𝐬𝐭𝐞𝐦 𝐃𝐞𝐬𝐢𝐠𝐧 1. Design a reusable modal/dialog system for a React application. 2. Design a toast/notification system that works across the entire app. 3. Design a dynamic form builder with nested fields and validations. 4. Design a reusable table/grid component with sorting, filtering, and pagination. 5. Design a drag-and-drop Kanban board like Trello. 6. Design a multi-step wizard form with validation and progress tracking. 7. Design a sidebar/navigation system that supports dynamic menus. 8. Design a theme provider system for dark/light modes. 9. Render a list of 10k+ items efficiently in React. 10. Implement infinite scrolling for large datasets. 11. Prevent unnecessary re-renders in a complex React component tree. 12. Design a search bar with debouncing, suggestions, and result highlighting. 13. Design a reusable file upload component with drag-and-drop support. 14. Design a consistent form validation and error messaging system. 15. Implement keyboard navigation and accessibility for interactive components. 16. Design a responsive dashboard layout with reusable widgets. 17. Optimize images, fonts, and static assets for faster page load. 𝐄𝐱𝐩𝐞𝐫𝐢𝐞𝐧𝐜𝐞𝐝 𝐋𝐞𝐯𝐞𝐥 𝐒𝐲𝐬𝐭𝐞𝐦 𝐃𝐞𝐬𝐢𝐠𝐧 1. Structure a large-scale React project used by multiple teams. 2. Design a shared component library used across multiple applications. 3. Architect a scalable state management solution for a complex frontend. 4. Design a feature flag / feature toggle system for frontend features. 5. Design a plugin-based dashboard where teams can add widgets. 6. Design a scalable grid/layout system for dashboards and admin panels. 7. Architect a micro-frontend system for multiple React applications. 8. Design a dashboard with resizable and customizable widgets. 9. Design a real-time chat or messaging UI. 10. Design the frontend architecture for a collaborative editor like Google Docs. 11. Implement API caching, retry, and error handling strategies. 12. Design optimistic UI updates for actions like likes, comments, and edits. 13. Implement offline-first support with local storage or IndexedDB. 14. Handle large nested API responses with proper data normalization. 15. Design a scalable internationalization (i18n) system. Over the past few months while preparing myself, I’ve been documenting these patterns, solutions, and interview workflows. Eventually it turned into a Frontend Interview Playbook, covering system design questions like these, machine coding patterns, debugging approaches, and how to use AI effectively during preparation. 𝗚𝗲𝘁 𝘁𝗵𝗲 𝗣𝗹𝗮𝘆𝗯𝗼𝗼𝗸 𝗵𝗲𝗿𝗲: https://lnkd.in/d8vBd3_j Use code FRONT10 for 10% off.

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Any SDE can switch to a good tech giant like Google, Atlassian, etc., only when they understand: 🔻Everyone does LeetCode, but companies aren’t just looking for problem solvers. 🔻They want engineers who can build real-world solutions, and  🔻If your resume lacks depth, you will be rejected despite your coding skills. So, focus on this: Started building projects with real-world impact. Explore new technologies, create scalable applications, and showcase the ability to solve practical problems. At least this is what helped me land a role. So, here’s what I have learned: ✔LeetCode is important, but it’s not enough. ✔Projects show your ability to build, not just solve. ✔ A strong resume is a mix of skills and real-world experience. So, if you’re grinding LeetCode endlessly, take a step back. And prepare fully. And if you need any help with your tech interview preparation you can get the help from mentors at Bosscoder Academy. Check them out here: https://bit.ly/43BI5Wp They’ve already helped 2200+ SDE’s crack top Product-Based Companies. Here’s how they can help you, too:  💡 A well-structured curriculum for DSA, System Design, and Full Stack Development. 💡 1:1 mentorship from industry experts. 💡 24/7 doubt support and interactive live classes. 💡 Real-world project building and 100% job switch assistance. #tips #leetcode #projects #brandpartnership #resume

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Most SDEs fall for these 3 myths during their switch to PBCs (Here’s how to not be one of them 👇) After 3 years in the industry & now working as an SDE-II at Microsoft, I’ve seen 1 thing clearly → Most engineers switching to top PBCs with service background struggle because of the MYTHS, not the actual prep. Here are the biggest ones I wish more people spoke about 👇 👉 MYTH #1: “If I learn one hot framework, I’m set.” REALITY: PBCs don’t hire for framework trivia. They hire for fundamentals, data modeling, concurrency, latency, trade-offs, clarity of reasoning. Frameworks change. Your thinking doesn’t. 👉 MYTH #2: “PBCs don’t care about on-call or ops work.” Reality: They value it a lot. Knowing how to prevent, detect, & fix failures shows maturity. If you’ve handled outages, escalations, dashboards, then talk about it proudly. 👉 MYTH #3: “Side projects must be huge to matter.” Reality: A small service with → ✔ metrics ✔ tracing ✔ a clear cache strategy ✔ clean APIs …shows far more engineering maturity than a half-finished giant clone. Switching to a PBC isn’t about doing more, it’s about doing the right things with clarity, structure, & consistency. And if you’re an SDE trying to prepare for their next switch after a busy 9-5, I’d strongly recommend giving Bosscoder Academy a try. 🔗 Explore their programs here: bcalinks.com/PsSqiXw They’ve helped 2200+ engineers crack top PBC roles through: 💡 Structured curriculum to help you master DSA, System Design, & AI 💡 Real world, AI-powered projects & 24/7 doubt-solving 💡 1:1 mentorship from industry experts 💡 Resume reviews, mock interviews, & 100% job switch support #myth #engineering #tech #job #career #growth #servicetoproduct #jobswitch #tech #collab

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Few months back i attended the WarnerBros interview for SDE 2, below are the questions that they asked. Q1. Minimum no. of platforms needed to accommodate trains based on arrival & departure times (DSA). Q2. Which version of Java are you using? What new features are you applying in day-to-day work? Q3. How do you connect to a MySQL DB using Spring Boot? Q4. What is a connection pool? How do you manage it, and what happens when the pool is exhausted? Q5. Purpose of RabbitMQ – how does it work, solve distribution, handle failures & acknowledgments? Q6. What is Elasticsearch? How does it query data so fast behind the scenes? Q7. If a user uploads a file with thousands of records, how do you design the system so the user sees “success” immediately while processing continues in background? Q8. How does PhonePe (or similar large-scale systems) handle deployments? Q9. Design notification service to push notification on mail, whatsapp etc.(LLD) 💡 I found these questions a great mix of core Java, DB, messaging systems, and distributed systems design. Would love to hear — which one would you pick first if asked in an interview? #Java #SpringBoot #SystemDesign #BackendDevelopment #InterviewPreparation

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Discord pays 1.5-2 crore for SDE-2 role and 1 crore for SDE-1 role How Discord Solved the @everyone Problem😱😱 - Discord initially partitioned data based on channel_id - When someone typed @everyone in a channel with hundreds of thousands of users, the system had to handle massive simultaneous queries. - This caused hot partitioning, where a single node became overloaded. - Since the system was quorum-based, latency from one node affected others — slowing down the entire cluster. - To fix this, Discord introduced a data service layer between the API and the database. This service was written in Rust for performance and safety. Goal: avoid querying the database millions of times for the same row. When @everyone was used: - The first user’s query hit the data service. A worker thread spun up to handle that request. - Other users’ queries subscribed to that worker instead of hitting the database. - Once the worker completed, all users received the message data simultaneously. Result: Millions of redundant database queries were eliminated, and system stability improved. Latency dropped from 150ms to 15 ms

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