Interaction design

Interaction design is designing how a product behaves rather than how it looks: what happens on the empty state, the slow connection, the second attempt, the error nobody planned for. It is the least visible design skill and the hardest to fake.

What the work consists of

Working through every state a screen can be in, and deciding what the product should do in each. The happy path is perhaps a fifth of the work. The rest is the long tail of ways reality fails to cooperate — which, on a mobile connection in a market where data is expensive, is not a long tail at all.

What employers screen for

The unhappy path. A portfolio showing only the successful flow tells a reviewer you have designed a demo. Showing what the interface does when the data is missing, the request times out, or the user enters something unexpected is the fastest way to be taken seriously, because it demonstrates you have shipped something real.

• Empty, loading, error and partial states designed rather than inherited
• Feedback: how the product tells someone it heard them
• Designing for a connection that drops, which is a local requirement and not an edge case
• Knowing which decisions belong to design and which are an engineering constraint

The honest limit

Six to twelve months to employable, and it is the slowest design skill to acquire because it needs real products with real failure modes to practise on. Redesigning a famous app’s home screen teaches almost none of it.