Design & User Experience Topics
User experience design, frontend architecture, and design systems. Includes UX principles, accessibility, and design documentation.
UI Component Design and Implementation
Capture the full lifecycle of designing implementing and hardening user interface components for production. This includes implementing interactive widgets such as autocomplete with API integration and keyboard navigation star rating controls accessible dropdowns and complex form widgets with validation and sanitization. It also covers larger UI patterns such as search and filter interfaces paginated or infinite scrolling lists and virtualization for performance. Interviewers should expect discussion of accessibility best practices focus management and ARIA attributes handling loading error and empty states mobile considerations keyboard interactions debouncing and throttling user input and strategies for testing and observing component behavior in integration. Candidates should demonstrate how they reason about state placement reuse performance trade offs and edge case handling in real products.
Responsive Design and Mobile First
Comprehensive understanding of responsive web design and the mobile first design approach, covering the full set of techniques used to make interfaces adapt across mobile, tablet, and desktop devices. Candidates should explain the rationale for designing mobile first and progressive enhancement, use of the viewport meta tag, and how to select and apply breakpoints. Core layout skills include fluid and flexible layouts, grid systems, and layout techniques such as Flexbox and Cascading Style Sheets Grid. Candidates should be familiar with relative sizing using percentages, em, rem, and viewport units, and with composing media queries to alter layout and behavior across viewport sizes. Important additional topics include responsive image strategies using the picture element and srcset and sizes attributes, support for high density or retina displays, touch friendly interaction patterns, accessibility considerations across devices and input types, performance implications for mobile networks, testing strategies across device sizes and browsers, and newer features such as container queries and aspect ratio controls when applicable.
Responsive and CSS Design
Focuses on building adaptable, maintainable user interfaces across devices and screen sizes using CSS and responsive design principles. Topics include mobile first and adaptive strategies, media queries, fluid and relative units, responsive images and picture sources, layout techniques using Flexbox and CSS Grid, responsive typography and spacing, component breakpoints and adaptive components, writing efficient and maintainable styles with methodologies like BEM or CSS in JS, CSS custom properties for theming, handling interactive states and accessible focus styles, performance considerations for layout and animations, and how responsive work intersects with accessibility (touch targets, readable text, focus management). Candidates should be ready to explain implementation details, trade offs, and examples of responsive patterns they used.
User Interface and User Experience Design
Covers the principles and execution of designing intuitive, usable, and polished digital interfaces. Topics include visual design fundamentals such as layout, visual hierarchy, typography, color, spacing, and contrast; accessibility considerations including color contrast, keyboard navigation, labeling, and assistive technology support; component and pattern design for consistent reusable interfaces; form design, navigation, and information architecture that guide user flows; interaction design and microinteraction practices including states for hover, focus, active, disabled, loading, and error, as well as feedback patterns and motion to communicate system status; handling edge cases and error states gracefully; responsive and platform specific design considerations; prototyping, design to implementation handoff, and basic usability validation and metrics. Candidates should be prepared to explain design decisions, demonstrate familiarity with trade offs between aesthetics and usability, and discuss how interaction details improve task completion and user satisfaction.
Taking and Implementing Feedback
Responding positively to interviewer suggestions, implementing changes gracefully, and building on feedback rather than getting defensive. Asking clarifying questions about feedback.
CSS and Responsive Design Issues
Identify common front end styling and responsiveness problems and propose pragmatic fixes. Look for missing or poorly applied media queries, fixed pixel sizing that breaks on small screens, inconsistent spacing and typography, unused or duplicated styles, and poor layout choices. Recommend mobile first breakpoints, flexible units, grid or flexbox layout patterns, and component level styling strategies. Consider performance impacts such as unnecessary repaints, heavy animations, and selector complexity, and suggest maintainability improvements like naming conventions and design tokens. Tie responsive and styling fixes to improved usability across devices.
State Management and Data Flow
Comprehensive coverage of strategies and patterns for managing application state and the flow of data in user interfaces and across system boundaries. Topics include local component state, derived state, and decisions about lifting state versus keeping it local; unidirectional data flow and event based updates; context providers and dependency injection for sharing state; and external state containers and libraries. Candidates should be able to explain criteria for selecting a solution based on application complexity, rendering performance, network characteristics, scalability, and team familiarity, and describe trade offs introduced by different libraries and architectures. Core engineering techniques include predictable state updates through immutability and pure update functions, minimizing duplicated and derived state, normalizing state shape, and designing for testability and debuggability. Synchronization concerns cover caching strategies and staleness models, when to refetch versus rely on cached data, optimistic and pessimistic update patterns and reconciliation, conflict resolution, and consistency across distributed front ends and server side systems. Also include considerations for rendering performance, concurrency, server side rendering, instrumentation, and debugging patterns used to reason about state in production.
Form Handling and Validation
Covers building and managing user input forms with correct markup and behavior, preventing duplicate submissions, and integrating with backend APIs. Includes client side validation rules such as required fields, format checking, length limits, and controlled versus uncontrolled component patterns in frameworks like React. Emphasizes clear, accessible error messaging and feedback for users, disabled states and loading indicators, input sanitization, and handling form specific edge cases such as empty submissions, partial input, and transient network failures.
Form Handling and Data Validation
Assess form implementation across user experience and system boundaries. Cover client side and server side validation strategies, input sanitization and protection against injection, cross field validation and error aggregation. Evaluate state management approaches for forms, including controlled and uncontrolled patterns, debouncing, optimistic updates and persistence of partial state. Review accessibility of form controls and error messaging, testing strategies for validation logic, and edge cases such as file uploads and international input formats. Discuss how validation decisions affect security and user experience.