Grokking the System Design Interview

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System Design Problems

  • System Design Interviews: A step by step guide
  • Designing a URL Shortening service like TinyURL
    • Let’s design a URL shortening service like TinyURL. This service will provide short aliases redirecting to long URLs.
    • Similar services:,,, etc.
    • Difficulty Level: Easy
    • KGS, Data Partition, Cache, Load Balance
  • Designing Pastebin
    • Let’s design a Pastebin like web service, where users can store plain text. Users of the service will enter a piece of text and get a randomly generated URL to access it.
    • Similar Services:,,
    • Difficulty Level: Easy
    • Metadata database and Object storage
  • Designing Instagram
    • Let’s design a photo-sharing service like Instagram, where users can upload photos to share them with other users.
    • Similar Services: Flickr, Picasa
    • Difficulty Level: Medium
  • Designing Dropbox
  • Designing Facebook Messenger
  • Designing Twitter
  • Designing Youtube or Netflix
  • Designing Typeahead Suggestion
  • Designing an API Rate Limiter
  • Designing Twitter Search
  • Designing a Web Crawler
  • Designing Facebook’s Newsfeed
  • Designing Yelp or Nearby Friends
  • Designing Uber backend
  • Design Ticketmaster (New)
  • Additional Resources

System Design Basics

  • Key Characteristics of Distributed Systems
  • Load Balancing
  • Caching
  • Sharding or Data Partitioning
  • Indexes
  • Proxies
  • Redundancy and Replication
  • SQL vs. NoSQL
  • CAP Theorem
  • Consistent Hashing
  • Long-Polling vs WebSockets vs Server-Sent Events


The most common types of NoSQL:

  • Key-Value Stores: Redis
  • Document Databases: MongoDB
  • Wide-Column Databases: HBase
  • Graph Databases

High level differences between SQL and NoSQL:

  • Storage
  • Schema
  • Querying
  • Scalability
  • Reliability or ACID Compliancy (Atomicity, Consistency, Isolation, Durability)

Reasons to use SQL database:

  • ensure ACID compliance.
  • data is structured and unchanging.

Reasons to use NoSQL database:

  • data is no structured
  • cloud computing
  • repid development

Consistent Hashing