Design Tokens

A cron job is a time-based task scheduler originating from Unix systems that runs commands or scripts at specified intervals. The schedule is defined using a cron expression with five fields representing minute, hour, day, month, and weekday. Cron jobs are fundamental for automations like database backups, log rotation, report generation, and periodic data synchronization.

The View Transitions API is a browser-native way to create animated transitions between different DOM states or page navigations, previously only possible with complex JavaScript animation libraries. It captures a snapshot of the current state, applies the DOM update, then animates between the old and new snapshots using CSS. This API works for both single-page app state changes and multi-page navigations, enabling smooth page transitions with minimal code that feels native to the platform.

Atomic Design is a methodology by Brad Frost for creating design systems by breaking interfaces into five hierarchical levels: atoms (basic HTML elements), molecules (simple component groups), organisms (complex UI sections), templates (page-level layouts), and pages (specific instances with real content). This approach provides a consistent mental model for organizing component libraries in React, React Native, or Flutter projects and ensures systematic scalability of the UI.

Drag and drop is an interaction pattern that lets users move, reorder, or transfer UI elements by clicking (or touching), holding, and dragging them to a new position. It's used for file uploads, kanban boards, sortable lists, and layout builders. The HTML Drag and Drop API provides native browser support, while libraries like dnd-kit and react-beautiful-dnd offer more polished, accessible, and touch-friendly implementations.

CSS Animation uses `@keyframes` rules and the `animation` property to create complex, multi-step animations entirely in CSS without JavaScript. Combined with CSS transitions for simple state changes, these tools handle most UI animation needs performantly since browsers can optimize them on the GPU compositor thread. Properties like `transform` and `opacity` are particularly efficient to animate because they don't trigger layout recalculations or repaints.

Usability testing is a UX research method where real users attempt to complete specific tasks while observers note difficulties, confusion, and behavior patterns. It can be moderated (with a facilitator) or unmoderated (self-guided with recording), and conducted on prototypes or live products. Even testing with just 5 users typically uncovers the majority of usability issues, making it one of the highest-ROI activities in product development.