Nielsen's 10 Usability Heuristics

Foundational principles for evaluating and designing usable interfaces. Apply these as a review checklist and as design constraints from the start — not only as a post-hoc audit tool.

1. Visibility of System Status

The design should always keep users informed about what is going on, through appropriate feedback within a reasonable amount of time.

Users cannot make good decisions without knowing the current state of the system. Trust is built through clear, timely feedback.

In practice:

• Show loading states, progress indicators, and completion confirmations
• Indicate where the user is in a multi-step process
• Reflect state changes immediately (optimistic UI or loading spinners)
• Never leave a user wondering whether an action was registered

Review question: After any user action, is the outcome visible within 1 second?