Framework

Imagine you want to build a house. You could start from absolute scratch — dig the foundation, pour concrete, frame every wall. Or you could start with a pre-built foundation and frame, and just customize it.

A framework is that pre-built foundation for software. Instead of writing every single piece of code from scratch, a framework gives you a structure to build on. It handles the boring, repetitive stuff so you can focus on what makes your app unique.

Next.js is a framework for building websites. Django is a framework for building backends. React is a framework for building user interfaces. Each one has opinions about how things should be organized, gives you tools and shortcuts, and saves you hundreds of hours of reinventing the wheel.

Because when someone says "what framework should I use?" they're really asking "what foundation should I build on?" Picking the right framework matters. It determines what's easy, what's hard, and what community of developers can help you when you get stuck. If you're vibe coding, your AI tool will need to know which framework you're using.

Frameworks provide opinionated structures for building applications. Frontend: React, Vue, Svelte, Angular. Full-stack: Next.js, Nuxt, SvelteKit. Backend: Express, Django, FastAPI, Rails. They typically include routing, state management, build tooling, and deployment patterns. Frameworks differ from libraries in that they control the flow — you plug into them, not the other way around (inversion of control).