SvelteKit is an officially supported framework, built around Svelte. components and libraries 118 # svelte-preprocess-markdown npm install svelte-preprocess-markdown Write Svelte components in markdown syntax integrations preprocessors 109 essence, SvelteKit is a tool for taking your Svelte code and converting it into a packaged app. Asking for help, clarification, or responding to other answers. Obviously that's the wrong mental model. You may need to review your build config to ensure that dependencies are compiled, rather than imported as pre-compiled modules at validate_component I have the following in my client config: Obviously after I figure out CSS colors, I no longer require the ColorTest pieces at all. By rejecting non-essential cookies, Reddit may still use certain cookies to ensure the proper functionality of our platform. Returns a Promise that resolves when the navigation is complete. When importing code from src/lib, instead of a relative path, you can use $lib. Why it's harder to do the authentication in SSR than SPA? The general idea is to let Svelte create a container and then hook into that container after its mounted with your third party library and fill it in. That javascript file is downloaded and executed immediately in the browser and builds the HTML DOM dynamically. Moving svelte-toolbox to a devDependency fixed the error. If you use SvelteKit's SSR with client-side hydration, you need to check whether the user is logged in in two parts of your application, in the backend side and the frontend side. : First import the createForm factory function in your component