sveltejs/kit · error · Error

Server files not found at ${dir}, did you run `build` first?

Error message

Server files not found at ${dir}, did you run `build` first?

What it means

Startup check in the preview server: it expects the build output at outDir/output/server (with a manifest.js) to exist before it can serve a production preview. This stackless error fires when vite preview runs before vite build, or when outDir was customized so the built server lives elsewhere.

Source

Thrown at packages/kit/src/exports/vite/preview/index.js:32

import { stackless } from '../../../utils/error.js';

/**
 * @param {PreviewServer} vite
 * @param {ValidatedConfig} svelte_config
 */
export async function preview(vite, svelte_config) {
	const { paths } = svelte_config;
	const base = paths.base;
	const assets = paths.assets ? SVELTE_KIT_ASSETS : paths.base;

	const protocol = vite.config.preview.https ? 'https' : 'http';

	const etag = `"${Date.now()}"`;

	const dir = join(svelte_config.outDir, 'output/server');

	if (!fs.existsSync(`${dir}/manifest.js`)) {
		throw stackless(`Server files not found at ${dir}, did you run \`build\` first?`);
	}

	const instrumentation = join(dir, 'instrumentation.server.js');
	if (fs.existsSync(instrumentation)) {
		await import(pathToFileURL(instrumentation).href);
	}

	/** @type {ServerInternalModule} */
	const { set_assets } = await import(pathToFileURL(join(dir, 'internal.js')).href);

	/** @type {ServerModule} */
	const { Server } = await import(pathToFileURL(join(dir, 'index.js')).href);

	/** @type {{ manifest: import('types').SSRManifest }} */
	const { manifest } = await import(pathToFileURL(join(dir, 'manifest.js')).href);

	set_assets(assets);

View on GitHub (pinned to 03f1687fe6)

Solutions

1. Run `vite build` before `vite preview`
2. Ensure the preview outDir matches the build outDir in the SvelteKit/Vite config
3. Rebuild after changing config so output/server/manifest.js is regenerated

When it happens

Trigger: Thrown at packages/kit/src/exports/vite/preview/index.js:32 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of sveltejs/kit@03f1687fe6 (2026-09-02). Data as JSON: /api/errors/61ca54addf357cb6. Report an issue: GitHub.