Static Sites: Same for Everyone
A static site is a collection of HTML, CSS, and JavaScript files that look the same to every visitor. The server just sends the files. There is no processing, no database, no user-specific logic. Your blog (if it has no comments), a portfolio site, a simple informational page -- these are static.
Static sites are fast, simple, and cheap to host. For content that does not change based on the user or user input, static is the right choice.
Dynamic Apps: Different for Each User or Input
A dynamic app processes requests and generates responses based on what the user sends or what is in a database. When you submit a form, the app receives the data and does something with it. When you log in, the app checks your credentials and shows you your personal dashboard. When a payment succeeds, the app updates your account status.
The test: does your site need to remember anything? Does it show different content to different people? Does it receive and process user input? If yes to any of these, you need a dynamic app.
What This Means for Your Replit Build
Most business applications are dynamic: they need to capture emails (form processing), show member content (authentication), display products (database), process payments (Stripe integration). The Express apps Claude builds are dynamic by default -- that is the right choice for any real business tool.
Frequently Asked Questions
What is the difference between a static site and a dynamic app?
A static site shows the same HTML content to every visitor. A dynamic app generates different content based on user input, database data, or user identity. Most business applications need to be dynamic.
When should I build a static site instead of a dynamic app?
When the content is informational and does not change based on the user or user input. A simple portfolio, a single-page product info site, or a landing page with no form are appropriate as static sites.
Are Express apps dynamic by default?
Yes. Express is a backend framework for building dynamic applications. Every route you define is a dynamic response -- even if it just serves a static HTML file, the routing logic is dynamic.
Can I convert a static site to a dynamic app later?
Yes, but it is easier to start with Express from the beginning if you know you will need dynamic features. Ask Claude to start with Express even for simple landing pages -- the overhead is minimal and it is much easier to add features later.
What is a React app and is it static or dynamic?
React is a JavaScript frontend framework that creates dynamic user interfaces. A React app can be frontend-only (fetching data from an API) or full-stack (with a backend). The Replit builds Claude creates typically use Express on the backend with HTML/JavaScript or React on the frontend.