Actually, the first web applications were server-side rendered (like PHP applications). SvelteKit is a relatively new SSR framework for SvelteJS. That means the server is only sending once a simple skeleton HTML with a javascript file inside. Obviously that's the wrong mental model. Making statements based on opinion; back them up with references or personal experience. SvelteKit can be considered the successor to Sapper or NextJS for Svelte. Once you are happy you can run `svelte-kit package` to create you component library. I ran into this error in my SvelteKit project. The hype around it just came back into the tech world a few years ago, after realizing that SPAs have many cons (and a lot of pros, of course). This is an example or POC of how to use SvelteKit with Firebase Auth and Firestore and how to model your Firestore for multi-tenancy. When working with svelte and sapper you to have think about 2 types of rendering : client side rendering (sveltjs, js) and server side rendering (SSR), it's sapper (nodejs or expressjs), there are a few ways to handle this, but according to the document of dependency you are using : for SSR you consider to import like this: SvelteKit has a special file called hooks. By clicking Sign up for GitHub, you agree to our terms of service and The components are pre-compiled to DOM code so its not usable in SSR. Does this happen only on components imported from cloudinary/svelte? You could apply a green or red border to indicate its valid or invalid state. You may need to review your build config to ensure that dependencies are compiled, rather than imported as pre-compiled modules.