sveltejs/kit · error · Error

The `generateManifest` adapter API has been removed — use `g

Error message

The `generateManifest` adapter API has been removed — use `generateServerInstance` or `builder.manifest` instead. You may need to update your adapter

What it means

SvelteKit removed the `generateManifest` Builder API from the adapt pipeline. Builders (adapters) still calling the old method hit a stub that throws, directing them to the replacement APIs `generateServerInstance` or `builder.manifest`.

Source

Thrown at packages/kit/src/core/adapt/builder.js:223

			const variables = explicit_env_config ?? {};

			/** @type {Record<string, StandardSchemaV1.Issue[]>} */
			const issues = {};

			for (const [name, config] of Object.entries(variables)) {
				if (config.static || !config.public) continue;
				values[name] = validate(variables, env[name], name, issues);
			}

			handle_issues(issues);

			const payload = devalue.uneval(values);

			write(`${dest}/env.js`, `export const env=${payload}`);
		},

		generateManifest() {
			throw new Error(
				'The `generateManifest` adapter API has been removed — use `generateServerInstance` or `builder.manifest` instead. You may need to update your adapter'
			);
		},

		generateServerInstance(dest, { routes: subset, serverDirectory } = {}) {
			const relative = relative_path(
				path.dirname(dest),
				serverDirectory ?? this.getServerDirectory()
			);
			write(
				dest,
				dedent`
					import { Server } from '${relative}/index.js';
					const manifest = ${generate_manifest({
						build_data,
						prerendered: prerendered.paths,
						relative_path: relative,
						routes: subset

View on GitHub (pinned to 03f1687fe6)

Solutions

1. Update the adapter package to a version supporting the new Builder API
2. Replace `generateManifest` usage in custom adapter code with `generateServerInstance` or `builder.manifest`
3. Pin SvelteKit to an older version only as a temporary stopgap

Example fix

// before (adapter)
const manifest = builder.generateManifest(routes);
// after
const instance = builder.generateServerInstance(dest, { routes, serverDirectory });

// custom adapter: feature-detect before calling
if (typeof builder.generateManifest === 'function' && builder.generateManifest.toString().includes('has been removed')) {
  throw new Error('Update adapter: use generateServerInstance or builder.manifest');
}

try {
  await adapter.adapt(builder);
} catch (e) {
  if (String(e.message).includes('generateManifest')) {
    console.error('Your adapter uses a removed SvelteKit API — upgrade it');
  }
  throw e;
}

When it happens

Trigger: An adapter's `adapt` implementation calls `builder.generateManifest(...)` during `pnpm build` / adaptation.

Common situations: Using an outdated third-party adapter written against the pre-removal Builder API after upgrading SvelteKit.

Related errors

• Instrumentation file ${instrumentation} not found. This is p
• Entrypoint file ${entrypoint} not found. This is probably a
• Instrumentation initializer ${initializer} not found. This i
• SvelteKit configuration (${keys}) no longer lives inside a `
• The `${keypath}` option has been removed. Please see the lis

AI-assisted analysis of sveltejs/kit@03f1687fe6 (2026-09-02). Data as JSON: /api/errors/a781a104675f8e6a. Report an issue: GitHub.