High-Level Design Document (HDD)

A High-Level Design Document (HDD) is a system design document that presents architectural overviews, major components, and design principles without implementation details.

• AKA: HLD, High-Level Design, Architecture Overview Document, System Overview Document.
• Context:
  • It can typically present System Architecture through architecture diagram.
  • It can typically define Component Relationship through component interaction.
  • It can typically establish Design Principle through principle documentation.
  • It can typically specify Technology Choice through technology justification.
  • It can typically outline System Boundary through boundary definition.
  • ...
  • It can often include Data Flow through flow diagram.
  • It can often describe System Interface through interface overview.
  • It can often establish Performance Goal through performance target.
  • It can often define Scalability Strategy through scaling approach.
  • ...
  • It can range from being a Minimal High-Level Design Document to being an Extensive High-Level Design Document, depending on its high-level design documentation scope.
  • It can range from being a Static High-Level Design Document to being an Evolutionary High-Level Design Document, depending on its high-level design change frequency.
  • It can range from being a Text-Based High-Level Design Document to being a Visual High-Level Design Document, depending on its high-level design representation style.
  • It can range from being a Traditional High-Level Design Document to being a Modern High-Level Design Document, depending on its high-level design methodology alignment.
  • It can range from being a Product High-Level Design Document to being a Platform High-Level Design Document, depending on its high-level design system type.
  • ...
  • It can integrate with Requirements Document for requirement alignment.
  • It can connect to Detailed Design Document for design refinement.
  • It can interface with Project Plan for milestone definition.
  • It can communicate with Test Strategy Document for test planning.
  • It can synchronize with Architecture Committee for design approval.
  • ...
• Example(s):
  • Web Application High-Level Design Documents, such as:
    • E-commerce High-Level Design Documents, such as:
      • Online Marketplace High-Level Design Document for marketplace platform architecture.
      • Payment System High-Level Design Document for payment processing architecture.
    • Social Media High-Level Design Documents, such as:
      • Content Sharing Platform High-Level Design Document for content distribution system.
      • Messaging Platform High-Level Design Document for real-time communication system.
  • Enterprise System High-Level Design Documents, such as:
    • ERP High-Level Design Documents, such as:
      • Manufacturing ERP High-Level Design Document for production management system.
      • Financial ERP High-Level Design Document for financial management system.
  • IoT System High-Level Design Documents, such as:
    • Smart Home High-Level Design Document for home automation architecture.
    • Industrial IoT High-Level Design Document for industrial monitoring system.
  • ...
• Counter-Example(s):
  • Detailed Design Document, which provides implementation-level details rather than architectural overviews.
  • Code Documentation, which describes code structures rather than system architecture.
  • User Manual, which explains system usage rather than system design.
• See: Software Architecture Design Document, System Design Document, Technical Design Document, Architecture Diagram, Design Specification, Solution Design Document, Conceptual Design Document.

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