svelte

Component not valid for SSR rendering

is not a valid SSR component

Fixes

1.Add export default to the component or check the import path
2.Ensure the component doesn't use browser APIs at top level
3.Wrap browser-only code in onMount() or check typeof window !== 'undefined'

sveltesveltekitssr

Related Errors

Svelte $ reactive syntax error

\$.*is not defined|\$state.*not allowed

•Ensure $ reactive declarations are at the top level of a .svelte file
•In Svelte 5, use $state() rune inside .svelte.ts files only with proper config

Lifecycle function called outside component initialization

lifecycle.*can only be.*during.*initialisation|onMount.*outside component

•Call onMount/onDestroy at the top level of the component script, not in callbacks
•Move lifecycle calls out of async functions or setTimeout

SvelteKit load function failure

load function.*error|\+page\.ts.*failed|load.*returned.*undefined

•Ensure load function returns an object (even empty {})
•Handle fetch errors with try/catch and return error() from @sveltejs/kit