Usability

Usability refers to how easy, efficient, and pleasant it is for users to accomplish specific goals with a product — for example a website or mobile app. It covers measurable aspects such as effectiveness (can users complete tasks), efficiency (how quickly and with how much effort), and satisfaction (how users experience the interaction). In web & mobile development, usability also requires attention to contextual factors like screen size, network conditions, accessibility, and familiar interaction patterns.

Imagine a mobile e-commerce site where the checkout flow has five unclear steps: buttons are small, error messages give no guidance, and pages load slowly. By improving usability you can reduce the flow to a single clear page, use larger, well-placed buttons, show inline validation with actionable messages, and optimize load times. After these changes you typically see higher conversion, fewer drop-offs during checkout, and improved scores in usability tests such as task completion rates and the SUS (System Usability Scale).