High Level Design (HLD)

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High Level Design (HLD)

Understanding High Level Design System


4 min read

High Level Design (HLD) is a general system design that incorporates the architecture and design of the project. HLD also includes a brief overview of components such as platforms, systems, services, and procedures. HLD documents comprise data flows, flowcharts, and data structures so that developers/implementers may understand how the system is intended to work in terms of features and design. It describes the relationship between the system's many components and functionalities. It defines the actual logic for each module of the system, as well as the design architecture to understand the flow of the system with function and database management system.

Customer business requirements are transformed into High Level Solutions as part of consultant work or architecture design - in network and security setups, this may include security Zones, traffic flows, and high level connectivity between numerous entities.


High level design should have two crucial components in order to describe a bird's eye view of the complete solution โ€”

  1. Component functionalities and properties/attributes
  2. Interactions and relationships between different components


The goal of this High Level Design (HLD) Documentation is to include the specific descriptions required to depict a viable model. This paper is intended to assist with operational requirements and to serve as a reference handbook for how the modules interact.

HLD is essentially a technical description of functional requirements and information exchange between assets or components.

The need of the project at the introductory phases of development is to identify those areas of the project that may be at risk or time demanding. HLD offers a quick summary of how the system's various subsystems and components interact.


The software architecture, application flow, and technology architecture are all presented in the High-Level Design documentation. In contrast to Low Level Design documentation, which should be entirely technical language, High Level Design documentation may contain certain non-technical words.


  • HLD displays and describes all design features (based on business needs and projected outcomes) in the form of a diagram.
  • It describes the user interface that is being implemented as well as the hardware and software interfaces.
  • It describes the performance requirements as well as the flow of the user's everyday processes.
  • HLD comprises the project's design elements and architecture.
  • Port numbers, VLAN, physical requirements, and so forth are not included in High Level Design.


HLD provides a brief description of the platforms/products/services/processes/traffic flow on which it is dependent, as well as any significant modifications that must be made to them.

HLD is the input for developing LLD (Low Level Design) because important communication elements are presented in HLD and then translated to comprehensive communication in LLD, displaying connection and physical level.

HLD necessitates the participation of a number of professionals from many professional areas such as SME, Design Architectures. Every type of end-user should be defined and specified in the HLD, and each contributing design should take the customer experience into account.

Another essential element is that HLD and LLD are sources of reference in the Operations stage, after the project has been effectively completed and is now in the BAU stage. As a result, the design step is crucial.

When is HLD created?

This is where High Level Design is established once the project requirements have been grasped and an overview of overall solution/system components communication needs to be carved out. HLD will be used as a starting point for the production of LLD or detailed designs. The knowledge accessible in HLD serves as the guiding concept for Low Level design, which must be demonstrated in detail. HLD is essential during โ€”

Early design โ€” During the preliminary stages, it is necessary to size the project and identify those aspects of the project that may be dangerous or time demanding.

Design overview โ€” As the project progresses, it is necessary to present an overview of how the different subsystems and components of the system mix in a frame.

Who creates HLD?

Solution architects are in charge of creating the HLD. They generate HLD, and then Subject Matter Experts or Designers work to construct LLD in accordance with the HLD criteria. LLD will include information on analysing traffic flow, designing network topology, IP addresses/VLANs, and device naming conventions in an organisation for seamless troubleshooting and operation.


HLD provides a comprehensive overview of a complete solution, product, system, platform service, service, or platform. High-level design (HLD) is an architectural technique that will describe the architectural design diagrammatically in a concise overview of the complete system.

About Me ๐Ÿ‘จโ€๐Ÿ’ป

I'm Faiz A. Farooqui. Software Engineer from Bengaluru, India. Find out more about me @ faizahmed.in

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