I have some doubts about non functional requirements in a web app. Are quality attributes non functional requirements? Also, these are all examples of non functional requirements?

  • The system should have a score >= 80 in PageSpeed
  • All network transactions should be encrypted
  • The users need to login to the system to access the administrator panel
  • 90% of new users should be able to perform the main tasks (task 1 and task 2) of the system without any error the first time they perform the task
  • The system should be compatible with the main browsers


  • Hi Carrick, on this site, askers are expected to do some research on their own before they ask. So what exactly are your own doubts/thoughts about the examples you gave? Please clarify, or don't be astonished if the community here will add more downvotes and close your question.
    – Doc Brown
    Commented Aug 27, 2018 at 17:40

1 Answer 1


The general rule that I follow for non-functional requirements are those things ending it "ilities", like: scalability, availability, reliability, etc... and then performance and security related requirements as well.

So, in your examples, here's how I would tag them:

  • PageSpeed (Performance: Nonfunctional)
  • Encrypted transactions (Security: Nonfunctional)
  • Admin panel (Security: Nonfunctional)
  • 90% of new users understand the system immediately (Usability: Nonfunctional)
  • Browser (Compatibility: Nonfunctional)

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