What is the difference between a web app and a website?

A website delivers content. A web app delivers functionality. The distinction matters for architecture, cost, and technology decisions.

A website is primarily read-only: visitors consume pages, read blog posts, browse products, fill out forms. The interaction model is simple — navigate, read, occasionally submit. Marketing sites, blogs, portfolios, and documentation are websites.

A web app is interactive: users create, edit, delete, and manipulate data. They have accounts, dashboards, settings, and workflows. The interaction model is complex — CRUD operations, real-time updates, file uploads, collaborative editing. Project management tools, CRMs, analytics dashboards, and SaaS products are web apps.

The gray area is large. An e-commerce site with a shopping cart is somewhere in between. A blog with user comments is mostly a website. A knowledge base with search and bookmarking is leaning toward app territory.

Why the distinction matters: websites should be static-first (SSG/ISR) for SEO and performance. Web apps should be client-rendered or server-rendered for real-time interactivity. Using app architecture for a marketing site wastes budget and hurts SEO. Using website architecture for an app creates poor user experience.

Cost comparison: a 10-page marketing website costs $15,000-$30,000. A web application with authentication, dashboards, and integrations costs $50,000-$200,000+.