Key terms and concepts in web development, AI, and software engineering explained in plain language.
An AI agent is an autonomous system that uses an LLM as its reasoning engine to plan, make decisions, and execute multi-step tasks by invoking tools and APIs. Unlike simple chatbots, agents can browse the web, write and run code, manage files, and chain actions together to accomplish complex goals. Frameworks like LangChain, CrewAI, and Anthropic's Agent SDK enable developers to build agentic applications.
ARIA (Accessible Rich Internet Applications) is a set of HTML attributes that provide additional semantics to assistive technologies like screen readers. Attributes such as `aria-label`, `aria-hidden`, and `role` help describe dynamic content, custom widgets, and interactive elements that native HTML alone cannot fully express. The first rule of ARIA is to not use it when a native HTML element with the same semantics already exists.
Accessibility (often abbreviated a11y) is the practice of designing and building websites and apps so they can be used by everyone, including people with visual, motor, auditory, or cognitive disabilities. This involves proper semantic markup, keyboard navigation support, sufficient color contrast, and screen reader compatibility. Beyond being an ethical responsibility, accessibility is increasingly a legal requirement in many jurisdictions.
An affordance is a design property that suggests how an element should be used — a raised button looks clickable, a handle looks draggable, an underlined text looks like a link. In UI design, perceived affordances guide users toward correct interactions without explicit instructions. When affordances are missing or misleading (like text that looks clickable but isn't), users experience confusion and frustration.
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.