High-Level Design (HLD) is the big-picture view of a software system. It describes the architecture, components, data flow, scalability, and trade-offs before a single line of code is written. This track teaches you how to think like a software architect.

Analogy: HLD is like the blueprint of a skyscraper — it shows the floor plan, elevator shafts, plumbing routes, and electrical grid. The actual construction (LLD / coding) happens later, guided by this blueprint.

flowchart LR
    Intro["01 Introduction<br/>What is HLD?"] --> Req["02 Requirements<br/>Functional & Non-Functional"]
    Req --> Cap["03 Capacity Estimation<br/>Traffic & Storage"]
    Cap --> Arch["04 Architecture Styles<br/>Monolith vs Microservices"]
    Arch --> LB["05 Load Balancers"]
    LB --> GW["06 API Gateway"]
    GW --> Cache["07 Caching Strategies"]
    Cache --> DB["08 Database Selection"]
    DB --> MQ["09 Message Queues"]
    MQ --> EDA["10 Event-Driven Architecture"]
    EDA --> CDN["11 CDN Design"]
    CDN --> Auth["12 Auth Architecture"]
    Auth --> File["13 File Storage"]
    File --> Mon["14 Monitoring & Observability"]
    Mon --> HA["15 High Availability"]
    HA --> DR["16 Disaster Recovery"]
    DR --> Cloud["17 Cloud Architecture"]
    Cloud --> Multi["18 Multi-Tenant Systems"]
    Multi --> RT["19 Real-Time Systems"]
    RT --> Interview["20 System Design Interviews"]

    style Intro fill:#7c3aed,color:#fff
    style Arch fill:#4f46e5,color:#fff
    style DB fill:#059669,color:#fff
    style HA fill:#f59e0b,color:#fff
    style Cloud fill:#ef4444,color:#fff
    style Interview fill:#6366f1,color:#fff

Each case study follows a consistent template: Problem → Requirements → Architecture → Components → Data Flow → Trade-offs → Scaling.

• Basic understanding of web applications (client-server model)
• Familiarity with databases (SQL and NoSQL concepts)
• Basic knowledge of networking (HTTP, TCP/IP)
• No prior architecture experience required — this track starts from fundamentals

• Each page follows a consistent template: Problem → Requirements → Architecture → Components → Data Flow → Trade-offs → Scaling → Interview Questions → Real-World Examples
• Mermaid diagrams illustrate every architecture and flow
• Pages end with key trade-offs and in simple words summaries
• Case studies apply everything you’ve learned to real-world systems

Start with 01 — Introduction to HLD to begin your journey!