Non-goal Articulation

Explicitly saying what you won't build is as valuable as saying what you will.

How It Works

Non-goals are features or concerns you explicitly exclude from the current design — "no video messaging," "no internationalization in v1," "no admin moderation tools." Why they matter: a system design interview has ~40 minutes, and every feature you accept into scope trades off time you can't spend on depth for the core features. Naming non-goals signals to the interviewer that you understand scope is a tradeoff, not an omission. It also prevents the trap where later in the interview the interviewer asks about something and you're forced to either hand-wave or scramble — you can point back to "we agreed that was out of scope." In interviews, list 2–3 non-goals immediately after scope decomposition, before diving deeper.

Real-World Example

When Stripe launched Payments, their scope had deliberate non-goals: no subscription management (came 2 years later as the Billing product), no fraud scoring (came 3 years later as Radar), no cross-border compliance at launch (rolled out per-country over 5 years). Stripe focused narrowly on "accept a card payment well" and shipped that world-class. Every deferred feature was revisited later as a standalone product with dedicated design. The initial non-goals weren't permanent exclusions — they were explicit deferrals that let the founding team ship the core correctly rather than shipping a mediocre everything.