Mobile app design
Designs apps for phones and tablets: small screens, finger input and use anywhere, often in a hurry.
What problem it addresses
An app is used on a small screen, with fingers (often the thumb of a single hand) and in short bursts, between other tasks and on the move. It also has to respect the conventions of iOS or Android, and ask for permissions and send notifications without abusing the trust of the people who use it.
Principles
Within thumb reach
Frequent actions go in the middle and lower part of the screen, where the thumb reaches, and at a size the finger can hit without effort.
Essentials first
Not everything fits on a small screen: each screen focuses on the main task and leaves the secondary one tap away.
Use in short bursts
People open the app for a minute, jump to another and come back; they should find it where they left it, without losing what they had typed.
Permissions at the right moment
Ask for access to location, the camera or contacts when the person uses the feature that needs it, and explain why in one clear sentence.
Each platform's conventions
On iOS and Android people expect different gestures, navigation and controls; follow them unless there is a good reason not to.
Applications in design
Use it like this
Put frequent actions in the part of the screen the thumb can reach.
Avoid
Cramming everything from the desktop version into the phone.
Don’t fall for it
Test the app on the street, in a hurry and with one hand, not just at your desk.
Connections
Authors and works
- 2011
Steven Hoober and Eric Berkman
Collected 76 interaction patterns for mobile interfaces.
- 2011
Luke Wroblewski
Proposed starting design with the phone screen to force yourself to decide what is essential.
- 2013
Steven Hoober
Made 1,333 observations of people using their phones on the street, in cafés and on public transport: of the 780 touching the screen, 49% did so with one hand.
Apple
Its interface guidelines describe the controls, gestures and patterns of its systems; for example, asking for a permission only when the person uses the feature that needs it.
Google
Material Design, its design system, gathers components, guidelines and reusable code; it is the reference for Android apps.
Sources
Original sources
- Apple (2008, March 12). iPhone SDK downloads top 100,000 [Nota de prensa]. Apple Newsroom. View source: Apple (2008, March 12)
- Hoober, S., & Berkman, E. (2011). Designing mobile interfaces. O’Reilly.
- Hoober, S. (2013, February 18). How do users really hold mobile devices? UXmatters. View source: Hoober, S. (2013, February 18)
- Wroblewski, L. (2011). Mobile first. A Book Apart.
- Apple (2026). Human Interface Guidelines. Apple Developer. View source: Apple (2026)
- Google (2026). Material Design 3. Google. View source: Google (2026)
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