Diagrammatic

Design a Live Comments Feature for Facebook — System Design Interview Practice

Design a real-time commenting system for posts with live updates and threading. Work through the requirements, architecture trade-offs, and an interactive design review.

Requirements and concepts to consider

  • Post and view comments in real-timeRequirement
  • Support nested/threaded commentsRequirement
  • Like and reply to commentsRequirement
  • Edit and delete commentsRequirement
  • Handle viral posts with thousands of commentsRequirement
  • Spam and profanity filteringRequirement
  • Support millions of comments per dayRequirement
  • Pagination for large comment threadsRequirement
  • real timeConcept to explore
  • commentsConcept to explore
  • websocketsConcept to explore
  • social mediaConcept to explore
  • threadingConcept to explore
Diagrammatic — system design practice and architecture review.