What is High Level Design?

High-level design or HLD refers to the overall system, a design that consists description of the system architecture and design and is a generic system design that includes:

• System architecture
• Database design
• Brief description of systems, services, platforms, and relationships among modules.

 What is High-Level Design Document? 

HLD document consists of data flows, flowcharts, and data structures to help developers in understanding and implement how the current system is being designed intentionally to function. 

This document is responsible for: 

• explaining the connections between system components and operations which depict the logic, and 
• architecture design needed (for the system’s functionality and flow) for each and every module of the system

as per the functional requirements. It is so because customer business requirements are transformed into solutions that we state as high-level designing as part of consulting work or architecture design, security, and networks.

HLD does not include physical requirements, port details, VLAN, and many other details.

Scope of High-Level Design Document 

The High-Level Design documentation presents the structure of the system as the application/database architecture, application flow, and technology architecture. High-Level Design documentation may use some non-technical terms, unlike low-level design which should be strictly technical jargon.

Note: Making the HLD is the responsibility of solution architects. After creating HLD, now expert experienced designers move towards LLD in accordance with the HLD’s criteria. LLD will provide details about how software entities will work whereas HLD focuses only on what software entities to place in an organization for efficient operation.

Here below constraints are expected from solution architects while designing HLD:

• Gathering both functional and non-functional requirements
• Costing Limitations (It becomes an important pillar once the system for the organization scales up)
• Strong bounds over the degree of consistency, availability, scalability, and performance of a system.