LLD Case Study Jun 21, 2026
Designing WhatsApp - Low Level Design
Learn how to build a WhatsApp in Java. This walkthrough covers a class diagram, object-oriented design patterns, and complete Java implementation.
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Tech Blog Jun 14, 2026
How Kafka Works - and Why You Probably Don't Need It
A clear explanation of how Apache Kafka works under the hood - topics, partitions, consumer groups, offsets - and an honest take on when Kafka is overkill.
#system-design#kafka#distributed-systems
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Tech Blog Jun 14, 2026
How Rate Limiting Works and How to Build One
How rate limiting works under the hood: fixed window, sliding window, token bucket, and leaky bucket. Includes a working Redis implementation and an LLD breakdown.
#system-design#lld#backend#api
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Tech Blog Jun 14, 2026
How Redis Works as a Cache - and When It Betrays You
Redis is fast until it isn't. Here's how Redis actually works as a cache - including eviction policies, cache stampede, and the failure modes most engineers miss.
#system-design#redis#caching#backend
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Tech Blog Jun 14, 2026
SQL vs NoSQL: The Real Answer
The actual tradeoffs between SQL and NoSQL databases - not the surface-level answer. When each breaks, why PostgreSQL is almost always the right start, and when NoSQL genuinely earns its place.
#system-design#databases#backend
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Tech Blog Jun 13, 2026
How Consistent Hashing Works (With a Real Example)
Regular hashing breaks every time you add or remove a server. Consistent hashing fixes that. Here is how the hash ring works and where you will actually run into it.
#system-design#distributed-systems#backend
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Tech Blog Jun 13, 2026
How Database Indexing Actually Works
Indexes are the difference between a query taking 50ms and 12 seconds. Here is how B-trees actually work, why composite index column order matters, and what silently breaks your indexes.
#database#backend#sql#system-design#performance
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Tech Blog Jun 13, 2026
How Docker Actually Works Under the Hood
Most developers use Docker without knowing what is actually happening when they run docker run. Here is what namespaces, cgroups, and image layers actually do.
#docker#backend#devops#linux#system-design
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Tech Blog Jun 13, 2026
How JWT Authentication Actually Works Under the Hood
Most developers use JWTs every day without knowing what's actually inside them. Here's how the signing, verification, and stateless auth actually works, and where it breaks.
#backend#security#auth#system-design
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Tech Blog Jun 13, 2026
How OAuth 2.0 Works, Explained Without the Confusion
OAuth 2.0 confuses most developers because it is poorly explained everywhere. Here is how it actually works, what the flows are for, and where people get it wrong.
#backend#security#auth#system-design
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Tech Blog Jun 13, 2026
WebSockets vs SSE vs Long Polling: When to Use What
WebSockets, SSE, and long polling all get data from server to client, but picking the wrong one costs you in complexity and infrastructure. Here is how to choose.
#backend#system-design#real-time#web
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LLD Case Study Jun 7, 2026
Design an AI Agent Tool Execution Coordinator
Learn how to build an AI Agent Tool Execution Coordinator in Java using the Mediator and Command patterns with agentic loop execution and context window pruning.
#lld#java
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LLD Case Study Jun 7, 2026
Design an API Gateway / Reverse Proxy
Learn how to build an API Gateway/Reverse Proxy in Java. Covers a class diagram, object-oriented design patterns and complete Java implementation.
#lld#java
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LLD Case Study Jun 7, 2026
Design a Collaborative Real-time Rich-Text Editor (CRDT/OT Engine)
Learn how to build a collaborative real-time rich-text editor in Java. Covers CRDT/OT eventual consistency conflict resolution algorithms.
#lld#java
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LLD Case Study Jun 7, 2026
Design a Coupon / Promo Code Validator Service
Learn how to build a Coupon/Promo Code Validator Service in Java using the Strategy pattern and Chain of Responsibility. Includes complete Java code.
#lld#java
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LLD Case Study Jun 7, 2026
Design a Multi-Stage Task Scheduler with DAG Execution
Learn how to build a multi-stage task scheduler with Directed Acyclic Graph (DAG) validation, cycle detection, and parallel thread-pool execution in Java.
#lld#java
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LLD Case Study Jun 7, 2026
Design a Database Connection Pool (HikariCP style)
Learn how to build a Database Connection Pool in Java. Covers a class diagram, object-oriented design patterns and complete Java implementation.
#lld#java
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LLD Case Study Jun 7, 2026
Design an Extensible Dependency Injection (DI) Container
Learn how to design a Dependency Injection (DI) container in Java with bean lifecycle management, recursive reflection resolution, and circular dependency detection.
#lld#java
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LLD Case Study Jun 7, 2026
Design a Circuit Breaker
Learn how to build a Circuit Breaker in Java. This walkthrough covers a class diagram, object-oriented design patterns, and complete Java implementation.
#lld#java
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LLD Case Study Jun 7, 2026
Design a Load Balancer
Learn how to build a Load Balancer in Java. This walkthrough covers a class diagram, object-oriented design patterns, and complete Java implementation.
#lld#java
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LLD Case Study Jun 7, 2026
Design a Payment Gateway / Aggregator
Learn how to build a Payment Gateway/Aggregator in Java. Covers a class diagram, object-oriented design patterns and complete Java implementation.
#lld#java
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LLD Case Study Jun 7, 2026
Design an Extensible Rules/Decision Engine
Learn how to build an extensible rules and decision engine in Java using Composite and Builder patterns to evaluate hierarchical rules dynamically.
#lld#java
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LLD Case Study Jun 7, 2026
Software Design Patterns for LLD Interviews: A Complete Guide
A complete guide to software design patterns for LLD interviews — covers Singleton, Observer, Strategy, Builder, Decorator, and more with Java code.
#lld#java
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LLD Case Study Jun 7, 2026
Design a Distributed / Concurrent Job Scheduler (Quartz / Cron style)
Learn how to build a Distributed/Concurrent Job Scheduler in Java using scheduled job execution and recurrence rules. Includes complete Java code.
#lld#java
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LLD Case Study Jun 7, 2026
Design an Event Sourcing & CQRS Framework
Learn how to design an Event Sourcing and CQRS framework in Java, featuring aggregate state reconstruction, real-time query projections, and an append-only event store.
#lld#java
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LLD Case Study Jun 7, 2026
Design a Excel Workbook (Spreadsheet with Formula)
Learn how to build an Excel Workbook in Java featuring thread-safe concurrency. Covers object-oriented design patterns and complete Java implementation.
#lld#java
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LLD Case Study Jun 7, 2026
Design a Financial Ledger Engine (Double-Entry Bookkeeping)
Learn how to design a double-entry bookkeeping financial ledger engine in Java, validating balance constraints, resolving concurrency, and avoiding float errors.
#lld#java
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LLD Case Study Jun 7, 2026
Design a Git Version Control System
Learn how to build a Mini-Git version control system in Java, covering file staging (add), snapshots (commit), branching, switching, and log history.
#lld#java
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LLD Case Study Jun 7, 2026
Design a Google Calendar Scheduler (with Complex Recurrence Rules)
Learn how to design a Google Calendar meeting scheduler in Java, covering dynamic conflict detection and complex recurrence rules expansion.
#lld#java
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LLD Case Study Jun 7, 2026
Design an In-Memory Cache (LRU/LFU with TTL)
Learn how to build an In-Memory Cache in Java. This walkthrough covers a class diagram, object-oriented design patterns, and complete Java implementation.
#lld#java
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LLD Case Study Jun 7, 2026
Design an In-Memory File System
Learn how to build an In-Memory File System in Java. Covers a class diagram, object-oriented design patterns and complete Java implementation.
#lld#java
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LLD Case Study Jun 7, 2026
Design a In-Memory Key-Value DB with Transactions (Redis-lite with Rollback)
Learn how to build an In-Memory Key-Value DB in Java. This walkthrough covers object-oriented design patterns, and complete Java implementation.
#lld#java
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LLD Case Study Jun 7, 2026
Design Local-First Sync Engine (Offline-Capable Client Store)
Learn how to build a client-side local-first synchronization engine in Java with offline command queueing and Last-Write-Wins conflict resolution.
#lld#java
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LLD Case Study Jun 7, 2026
Design Log Analyzer and Parser (Indexed Search Engine)
Learn how to design a log analyzer and search engine in Java using inverted index mapping and boolean search query evaluation.
#lld#java
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LLD Case Study Jun 7, 2026
Design a Logging Library/Framework (Log4j/Logback style)
Learn how to build a Logging Library/Framework in Java. Covers a class diagram, object-oriented design patterns and complete Java implementation.
#lld#java
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LLD Case Study Jun 7, 2026
Design a Model Context Protocol (MCP) Router
Learn how to build a Model Context Protocol (MCP) tool router in Java to parse and route JSON-RPC 2.0 requests from AI clients.
#lld#java
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LLD Case Study Jun 7, 2026
Design an Order Matching Engine (Stock Brokerage System)
Learn how to build an Order Matching Engine in Java. Covers a class diagram, object-oriented design patterns and complete Java implementation.
#lld#java
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LLD Case Study Jun 7, 2026
Design a Package Manager/Installer with Dependency Resolution
Learn how to design a package manager in Java with topological sorting for dependency installation and cycle detection.
#lld#java
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LLD Case Study Jun 7, 2026
Design a Prompt Management & Template Engine
Learn how to build a Prompt Management and Template Engine in Java using the Strategy, Factory, and Builder patterns. Includes complete Java code.
#lld#java
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LLD Case Study Jun 7, 2026
Design a Quick commerce Delivery system like Amazon Now, Swiggy Instamart / Zepto (10-Minute Delivery LLD)
Learn how to build a Quick Commerce Delivery System in Java. This walkthrough covers object-oriented design patterns, and complete Java implementation.
#lld#java
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LLD Case Study Jun 7, 2026
Design a Saga Orchestrator for Distributed Transactions
Learn how to build a Saga Orchestrator in Java featuring thread-safe concurrency. Covers object-oriented design patterns and complete Java implementation.
#lld#java
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LLD Case Study Jun 7, 2026
Design a Trello / Jira-lite Board
Learn how to build an in-memory Trello/Jira-lite task planning board in Java, covering workspaces, custom list state management, and audit trails.
#lld#java
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LLD Case Study Jun 7, 2026
Design an In-Memory Vector Search Engine (Vector Database-lite)
Learn how to design an in-memory high-dimensional vector search engine in Java with cosine similarity and K-Nearest Neighbors (K-NN) search.
#lld#java
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LLD Case Study May 26, 2026
Design a Customer Issue Resolution System
Learn how to build a Customer Issue Resolution System in Java. Covers a class diagram, object-oriented design patterns and complete Java implementation.
#lld#java
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LLD Case Study May 26, 2026
Design a Airline Reservation System
Learn how to build an Airline Reservation System in Java. Covers a class diagram, object-oriented design patterns and complete Java implementation.
#lld#java
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LLD Case Study May 26, 2026
Design a ATM system
Learn how to build an ATM System in Java. This walkthrough covers a class diagram, object-oriented design patterns, and complete Java implementation.
#lld#java
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LLD Case Study May 26, 2026
Design a Chess Game
Learn how to build a Chess Game in Java. This walkthrough covers a class diagram, object-oriented design patterns, and complete Java implementation.
#lld#java
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LLD Case Study May 26, 2026
Design a Food Delivery/Ordering System
Learn how to build a Food Delivery/Ordering System in Java. Covers a class diagram, object-oriented design patterns and complete Java implementation.
#lld#java
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LLD Case Study May 26, 2026
Design a Hotel Management/Booking System
Learn how to build a Hotel Management/Booking System in Java. Covers a class diagram, object-oriented design patterns and complete Java implementation.
#lld#java
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LLD Case Study May 26, 2026
Design a Library Management System
Learn how to build a Library Management System in Java. Covers a class diagram, object-oriented design patterns and complete Java implementation.
#lld#java
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LLD Case Study May 26, 2026
Design a Meeting Scheduler System
Learn how to build a Meeting Scheduler System in Java. Covers a class diagram, object-oriented design patterns and complete Java implementation.
#lld#java
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LLD Case Study May 26, 2026
Design a Notification System
Learn how to build a Notification System in Java supporting multi-channel notifications via email, SMS, and push. Includes complete Java code.
#lld#java
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LLD Case Study May 26, 2026
Design a Online Bookstore System
Learn how to build an Online Bookstore System in Java. Covers a class diagram, object-oriented design patterns and complete Java implementation.
#lld#java
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LLD Case Study May 26, 2026
Design a Rate Limiter system
Learn how to build a Rate Limiter System in Java covering sliding window and fixed window rate limiting algorithms. Includes complete Java implementation.
#lld#java
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LLD Case Study May 26, 2026
Design a Ride-Sharing/Booking system
Learn how to build a Ride-Sharing/Booking System in Java. Covers a class diagram, object-oriented design patterns and complete Java implementation.
#lld#java
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LLD Case Study May 26, 2026
Design a Shopping Cart system
Learn how to build a Shopping Cart System in Java. Covers a class diagram, object-oriented design patterns and complete Java implementation.
#lld#java
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LLD Case Study May 26, 2026
Design a Splitwise system
Learn how to build a Splitwise System in Java. This walkthrough covers a class diagram, object-oriented design patterns, and complete Java implementation.
#lld#java
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LLD Case Study May 26, 2026
Design an Elevator/Lift system
Learn how to build an Elevator/Lift System in Java. Covers a class diagram, object-oriented design patterns and complete Java implementation.
#lld#java
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LLD Case Study May 26, 2026
Design an E-commerce/Online Shopping system
Learn how to build an E-Commerce/Online Shopping System in Java. Covers a class diagram, object-oriented design patterns and complete Java implementation.
#lld#java
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LLD Case Study May 26, 2026
Design a File Storage System like Google Drive/ DropBox
Learn how to build a File Storage System in Java covering file permissions and storage, object-oriented design patterns, and complete Java code.
#lld#java
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LLD Case Study May 26, 2026
Most Frequently Asked Low Level Design(LLD) Interview Questions
A curated list of the most commonly asked LLD interview problems, each with complete Java code, class diagrams, and design pattern explanations.
#lld#java
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LLD Case Study May 26, 2026
Design a Movie Ticket Booking system
Learn how to build a Movie Ticket Booking System in Java. Covers a class diagram, object-oriented design patterns and complete Java implementation.
#lld#java
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LLD Case Study May 26, 2026
Design a Order Inventory Management System
Learn how to build an Order Inventory Management System in Java. Covers a class diagram, object-oriented design patterns and complete Java implementation.
#lld#java
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LLD Case Study May 26, 2026
Design a Real-time Chat Application
Learn how to build a Real-Time Chat Application in Java. Covers a class diagram, object-oriented design patterns and complete Java implementation.
#lld#java
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LLD Case Study May 26, 2026
Design a Snake and Ladder game
Learn how to build a Snake and Ladder Game in Java. Covers a class diagram, object-oriented design patterns and complete Java implementation.
#lld#java
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LLD Case Study May 26, 2026
Design a Social Media Platform like Facebook
Learn how to build a Social Media Platform in Java. Covers a class diagram, object-oriented design patterns and complete Java implementation.
#lld#java
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LLD Case Study May 26, 2026
Design a Text Editor/Word Processor like Microsoft Word
Learn how to build a Text Editor/Word Processor in Java. Covers a class diagram, object-oriented design patterns and complete Java implementation.
#lld#java
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LLD Case Study May 26, 2026
Top 10 Low Level Design (LLD) Interview Questions
The top 10 low-level design interview questions with complete Java solutions, class diagrams, and thorough explanations of object-oriented design.
#lld#java
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LLD Case Study May 16, 2026
Designing a Parking Lot - Low Level Design
Learn how to build a Parking Lot in Java. This walkthrough covers a class diagram, object-oriented design patterns, and complete Java implementation.
#lld#java
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SDE Playbook May 7, 2026
Software Engineer Resume Templates (ATS-Friendly)
Top software engineer resume templates (ATS-friendly) for FAANG/MAANG roles. Curated Word & LaTeX layouts for Google, Amazon, Microsoft, and Meta.
#resume#career#ats-friendly#faang
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