Functional and Non-Functional Requirements

Functional and Non-functional requirements are those statements that specify what the system should do.

Functional Requirements describe the behavior of the system; while on-functional requirements state a characteristic of the performance. For example: The functional requirement of a table is to hold objects, while the non-functional requirement is to hold up to 50kg.

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Some examples of Functional and Non-Functional requirements:

Functional Requirements

  • Business Rules
  • Transaction corrections, adjustments and cancellations
  • Administrative functions
  • Authentication
  • Authorization levels
  • Audit Tracking
  • External Interfaces
  • Certification Requirements
  • Reporting Requirements
  • Historical Data
  • Legal or Regulatory Requirements

Non-Fuctinal Requirements

  • Performance
  • Scalability
  • Capacity
  • Availability
  • Reliability
  • Recoverability
  • Maintainability
  • Serviceability
  • Security
  • Regulatory
  • Manageability
  • Environmental
  • Data Integrity
  • Usability
  • Interoperability



StackOverflow. (2015). what is functional and non functional requirement. August 8th, 2016, from StackOverflow. Website:

Ulf, E. (2012). Functional vs Non Functional Requirements. August 8th, 2016, from ReQtest. Website: