A Few Pointers on Non-functional Requirements

Non-functional requirements (NFRs) are like the unstuffed crust of a pizza: they are the least exciting part of the spec & are often left untouched.

However, for many features, those parameters can be the difference between success & failure.

For example, imagine Uber took longer than a few minutes to match a rider to a driver.

Or Fortnite was unable to support more than 10 concurrent players.

Or a payment interface page had no security certificate.

Or a mission-critical server had less than 99% uptime.

Or a medical device came with no failsafe mechanism.

Or a text-based OTP was sent after its expiry.

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A few pointers on NFRs:
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1. They need to be measurable & testable. "The search needs to be fast" is a wish, not a NFR.
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2. Consider NFRs when dealing with search, notifications, alerts & concurrency.
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3. For marketplaces & e-commerce pages, important SEO requirements like meta-tags are packaged as NFRs.
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4. Typically, the more stringent the NFR, the higher the development cost. Therefore, always aim for acceptable benchmarks, not needlessly ambitious numbers.