Micro-frontends break frontend monoliths into small, independently deployed features that communicate via lightweight APIs, boosting scalability, parallel development, maintenance, and resilience; they demand modular JS, web components, state management, inter-app messaging, CSS-in-JS, and strong build/deploy tooling; use vertical/horizontal splits and frameworks like single-spa; expect added complexity, integration hurdles, and tougher debugging (e.g., GreenMart e-commerce).