What are Functional Requirements in System Design? | Examples, Definition

Functional requirements are an important aspect of system design and development and describe the specific functionalities or behaviors that a system or software application must perform to satisfy user needs, business requirements, and stakeholder expectations. These requirements detail what the system should do and how it should behave under certain conditions. Functional requirements are typically documented during the requirements-gathering phase and serve as the basis for system design, development, testing, and validation.

Why the Functional Requirements are Documented?

• Clarifying Stakeholder Expectations:
  • Documenting functional requirements helps clarify and formalize stakeholder expectations regarding what the system should do and how it should behave. This ensures that all parties involved have a clear understanding of the desired functionalities.
• Providing a Blueprint for Development:
  • Functional requirements serve as a blueprint or roadmap for the development team, guiding them in the design, implementation, and testing of the system's functionalities. Developers refer to these requirements to understand the scope of work and the specific features they need to build.
• Facilitating Communication:
  • Functional requirements provide a common language and communication tool for stakeholders, project managers, developers, testers, and other team members involved in the project. They help facilitate effective communication and collaboration by ensuring that everyone is on the same page regarding the system's requirements.
• Managing Scope:
  • Documenting functional requirements helps manage project scope by clearly defining the boundaries of the system's functionalities. Any changes or additions to the requirements can be evaluated against the documented scope to assess their impact on the project timeline, budget, and resources.

Functional Requirements Example

Let us consider a simple example of Functional Requirements for an online bookstore system

User Functions:

• Users should be able to register for a new account by providing their name, email address, and password.
• Registered users should be able to log in to the system using their username/email and password.
• Users should be able to browse through the list of available books by category such as genre, author, or popularity.
• Users should be able to view detailed information about a selected book, including its title, author, description, price, availability, and reviews.
• Users should be able to add selected books to their shopping cart for purchase.
• Users should be able to proceed to checkout, enter billing and shipping information, and complete the purchase.
• Users should be able to update their account information, including name, email address, password, and shipping address.

Administrative Functions:

• Administrators should be able to manage the inventory of books, including adding new books, updating book information, and removing discontinued books.
• Administrators should be able to view and respond to customer inquiries, feedback, and support requests.
• Administrators should be able to manage orders, view order details, and update order statuses as needed.