What are Functional Requirements? Definition & Examples

Max 5min read

Ready to explore the world of functional requirements? Let’s dive in and discover what they’re all about.

Functional requirements play a vital role in software development. They define the specific tasks and features a system needs to perform to meet the needs of its users. In simpler terms, they are like a rulebook that guides the design and functionality of a software product.

Let’s consider a mobile banking app to give you a clearer picture. Some functional requirements for this app would include allowing users to check their account balance, transfer funds, and view transaction history. These requirements ensure the app has all the features users expect from a banking platform.

In essence, functional requirements are a software system’s foundation, ensuring it delivers the desired functionalities and meets user expectations. So, let’s dig deeper and explore the fascinating world of functional requirements together!

What are Functional Requirements

Definition of Functional Requirements

Functional requirements specify the behavior and capabilities of a software system. They detail the desired outcomes, functions, and interactions that users expect from the software.

Functional requirements serve as the guiding principles in software development, outlining the specific tasks and functionalities that a system must possess to fulfill the needs of its users. They define what a software product should do.

Imagine functional requirements as the blueprint that architects the design and functionality of a system. They outline the software’s essential features and actions, ensuring it operates smoothly and meets user expectations.

For instance, functional requirements in a mobile banking application might encompass functionalities like account balance checking, fund transfers, and transaction history viewing. These requirements ensure that the app offers the capabilities expected from a banking platform.

Functional vs Non-Functional Requirements

Functional RequirementsNon-Functional Requirements
FocusWhat the system should doHow well the system should perform
DescribesSpecific functions and capabilitiesOverall qualities and characteristics
EmphasizeSystem behavior and functionalitySystem performance and attributes
ExamplesUser authentication, data validation,Performance, reliability, security, usability, scalability,
Report generation, search functionalityMaintainability, availability, etc.
ConcernsActions and behaviors of the systemEffectiveness, efficiency, and quality standards
EvaluationDetermined by verifying system behaviorAssessed by measuring system performance and meeting standards
ImportanceEssential for meeting users’ needsCrucial for ensuring system effectiveness and user satisfaction
ImpactDirectly affects the system’s functionalityIndirectly impacts the user experience and system performance
Comparison chart of Functional vs Non-Functional Requirements

Remember, both functional and non-functional requirements are important for developing a successful system. While functional requirements define the specific features and actions of the system, non-functional requirements ensure that the system meets the desired quality standards and constraints.

Types of Functional Requirements

You can categorize functional requirements into several types based on the nature of the functionality they describe. Here are some common types of functional requirements:

Business Process Requirements

These requirements describe the specific business processes and workflows that the system must support. They outline the steps, actions, and interactions required to complete various tasks within the system.

User Interface Requirements

User interface requirements specify how the system’s interface should get designed and how users will interact with it. They define the user interface’s layout, navigation, input controls, and visual elements.

Data Requirements

Data requirements define the data elements, structures, and relationships the system must capture, store, manipulate, and present. They specify the types of data to be processed, the required data validations, and any data constraints or business rules that apply.

Functional Performance Requirements

These requirements define the expected performance characteristics of the system in terms of response time, throughput, resource utilization, and capacity. They ensure the system can handle the anticipated workload and perform its functions efficiently.

Security Requirements

Security requirements outline the measures and controls that must get implemented to protect the system and its data from unauthorized access, breaches, or misuse. They cover authentication, authorization, data encryption, audit trails, and compliance with security standards.

Integration Requirements

Integration requirements specify how the system should interact and exchange data with external systems or components. They define the interfaces, protocols, and data formats required for seamless integration and interoperability.

Reporting and Analytics Requirements

These requirements describe the system’s capabilities for generating reports, conducting data analysis, and presenting insights. They outline the specific reports, metrics, charts, or dashboards the system should provide to support decision-making and monitoring.

Compliance and Legal Requirements

Compliance and legal requirements encompass any legal, regulatory, or industry-specific standards the system must adhere to. They ensure that the system meets legal and regulatory obligations, such as data privacy, accessibility, or industry-specific regulations.

How to Write Functional Requirements

Writing functional requirements effectively involves following certain principles. Here’s a summary of the key guidelines:

  • Be Clear and Concise: Use clear and straightforward language to convey the intended functionality. Avoid ambiguity or unnecessary complexity.
  • Use Unambiguous Language: Ensure your requirements are clear and free from multiple interpretations. Be precise and avoid vague or ambiguous terms.
  • Use Consistent Terminology: Maintain consistency in the terminology used throughout your requirements document. Employ the same terms to refer to the same concepts consistently.
  • Be Specific: Provide detailed descriptions of the desired functionality, including inputs, outputs, conditions, and constraints. Avoid general statements or broad descriptions.
  • Be Measurable: Make your requirements measurable whenever possible. Define criteria or metrics that you can use to evaluate whether you have successfully implemented functionality.

Examples of Functional Requirements

Here are some examples that demonstrate the application of the guidelines:

  • The system must allow users to create, edit, and delete records: Users should be able to create new records, modify existing records, and delete records from the system. This functionality is crucial for managing and maintaining data.
  • The system must provide users with a search function: Users should be able to search for specific information. This feature allows users to locate relevant records or data based on specific criteria, enhancing the system’s usability and efficiency.
  • The system must be able to handle 100 concurrent users: The system should have the capability to support and handle a minimum of 100 users simultaneously. This requirement ensures that the system can accommodate a substantial number of users without experiencing performance issues or slowdowns.
  • The system must be available 24/7: The system should be accessible to users all the time without any scheduled downtime. This requirement ensures that users can utilize the system whenever they need to, regardless of the time or day.
  • The system must be secure: The system should implement proper security measures to protect sensitive data and prevent unauthorized access. This requirement ensures that user information and system data remain confidential and protected from potential threats.

These examples illustrate different functional requirements that describe specific features and capabilities the system should possess to fulfill user needs effectively.


How do you identify functional requirements?

Identifying functional requirements involves understanding the specific functionalities and capabilities that a system or software needs to have. This is through gathering and analyzing user requirements, conducting interviews, discussing with stakeholders, and documenting the desired system behavior. Functional requirements describe what the system should do and how it should perform specific tasks.

What are the functional requirements in project management?

In project management, functional requirements refer to the specific features, capabilities, and behaviors a system or software must possess to meet the project objectives. These requirements focus on describing what the system should do rather than how it should get implemented. Functional requirements serve as a foundation for designing, developing, and testing the system to ensure that it meets the desired functionality.

Who writes functional requirements?

Functional requirements are typically written by business analysts, product managers, or system analysts who work closely with stakeholders and end-users to gather and document the requirements. These professionals collaborate with stakeholders to understand their needs and expectations and then translate them into clear and concise functional requirements. The process may involve iterations and feedback loops to ensure that the requirements accurately capture the desired system functionalities.


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