Non-functional_requirement

# Non-functional requirement ## Links (Wikipedia order)  `Accessibility` · [[Accuracy_and_precision]] · [[Adaptability]] · [[Algorithmic_efficiency]] · `Architecturally_significant_requirements` · [[Availability]] · `Backup` · `Backward_compatibility` · [[Black_box]] · `Certification` · `Computer_performance` · [[Computer_programming]] · `Computer_security` · [[Configuration_management]] · `Conformance_testing` · [[Correctness_(computer_science)]] · `Data_integrity` · `Data_retention` · `Documentation` · `Durability` · `Effectiveness` · `Efficacy` · `Efficiency` · `Environmental_protection` · [[Extensibility]] · `FURPS` · `Factor_of_safety` · [[Fault_tolerance]] · [[Flexibility_(engineering)]] · `Function_(mathematics)` · `Functional_requirement` · `IPO_model` · `ISO/IEC_9126` · `Internationalization_and_localization` · `Interoperability` · `List_of_system_quality_attributes` · [[Loose_coupling]] · [[Maintainability]] · `Mean_time_between_failures` · `Mean_time_to_repair` · `Misnomer` · `Network_topology` · `O'Reilly_Media` · `Open_source` · `Operability` · [[Orthogonality_(programming)]] · `Performance_engineering` · `Privacy` · `Quality_(business)` · [[Real-time_computing]] · `Reliability,_availability,_maintainability_and_safety` · [[Reliability_engineering]] · `Requirement` · `Requirements_analysis` · [[Requirements_engineering]] · [[Reusability]] · [[Robustness_(computer_science)]] · `Safety` · [[Scalability]] · `Schedule_(project_management)` · `Serviceability_(computer)` · [[Software_architecture]] · `Software_deployment` · [[Software_portability]] · [[Software_quality]] · [[Software_quality_assurance]] · [[Software_quality_control]] · [[Software_quality_management]] · [[Software_sizing]] · [[Software_testability]] · `Stability_model` · `System_integration` · `Systems_architecture` · `Systems_design` · [[Systems_engineering]] · `Thoughtworks` · `Training` · `Transparency_(behavior)` · [[Usability]] > Summary stub · part of System Quality Attributes · [Wikipedia source](https://en.wikipedia.org/wiki/Non-functional_requirement) ## Summary A non-functional requirement specifies criteria that judge the operation of a [[System|system]], as opposed to specific behaviors or functions. Non-functional requirements define system quality attributes such as performance, reliability, security, [[Usability|usability]], and [[Maintainability|maintainability]]. They specify constraints and conditions under which the system must operate and describe how well the system must perform its functions. Non-functional requirements are essential for translating business goals into measurable quality attributes and architectural decisions. ## Key points - Specifies criteria judging operation quality versus specific behaviors - Defines quality attributes: performance, reliability, security, usability, maintainability - Establishes constraints and conditions for system operation - Translates business goals into measurable architectural decisions ## Relation to System Quality Attributes This article connects to system quality attributes as non-functional requirement directly influences how systems are designed, evaluated, and operated. It contributes to understanding the broader [[Ecosystem|ecosystem]] of quality concerns, from high-level requirements and [[Architecture|architecture]] patterns down to specific measurable attributes and [[Engineering|engineering]] practices. ## Sources - [Non-functional requirement — Wikipedia](https://en.wikipedia.org/wiki/Non-functional_requirement) Back to System Quality Attributes ---  ## Semiotic profile > *The semiotic universals this article invokes, machine-derived from the crossref — **unverified** (born so). Populated 2026-07-06 for the Systems room.* **Universals (3):** 🟡 system (13) · 🟢 measurement (3) · 🟡 architecture (2) **Enter by sign:** Systems Semiotic Gateway · Alphabetum · Icon Registry · ← Systems Portal  ## Wikipedia : Wikitube **Strict pair:** [Wikipedia](https://en.wikipedia.org/wiki/Non-functional_requirement) : [Wikitube](https://en.wikitube.io/wiki/Non-functional_requirement) ## Previous hub tags Tree parent: [[Reliability_engineering]]. Legacy hubs: none. --- *Sources: 1 legacy note. Minted wave 1, 2026-07-30 (v1.6 order).*