Deployment

If the dev server is the rehearsal, deployment is opening night. You put the build output on a machine that's always online and give it a URL. Fully static sites (SPA, SSG) can go on a static hosting service or CDN. Projects that need SSR or backend APIs have to be deployed to a platform or server that can run Node.js.

A common setup is to push your code to a Git repo, and a hosting platform (like Vercel or Netlify) detects the new commit, builds it, and puts it live automatically. This is called continuous deployment.

Common problems after launch: works locally but errors in production, usually because an Environment Variable isn't set on the platform. Refreshing a sub-page gives a 404, because the single page app fallback rule isn't set up. API requests fail, possibly because of CORS, or because the API URL still points to localhost.