withastro/astro · warning

The local Node.js version (${major}) is not supported by V

Error message

	The local Node.js version (${major}) is not supported by Vercel Serverless Functions.
	Your project will use Node.js 24 as the runtime instead.
	Consider switching your local version to 24.

What it means

While generating per-function .vc-config.json files, the Vercel adapter maps the local Node.js major version to a Vercel serverless runtime via SUPPORTED_NODE_VERSIONS. If the major running the build is not a key in that table (e.g. an odd-numbered, very new, or EOL-and-removed release), getRuntime() warns and pins the deployed functions to nodejs24.x instead, so production runtime differs from your local one.

Source

Thrown at packages/integrations/vercel/src/index.ts:792

			new URL('./middleware.mjs', functionFolder),
			middlewareSecret,
			this.logger,
			isrForwarding,
		);

		await writeJson(new URL(`./.vc-config.json`, functionFolder), {
			runtime: 'edge',
			entrypoint: 'middleware.mjs',
		});
	}
}

function getRuntime(process: NodeJS.Process, logger: AstroIntegrationLogger): Runtime {
	const version = process.version.slice(1); // 'v18.19.0' --> '18.19.0'
	const major = version.split('.')[0]; // '18.19.0' --> '18'
	const support = SUPPORTED_NODE_VERSIONS[major];
	if (support === undefined) {
		logger.warn(
			`\n` +
				`\tThe local Node.js version (${major}) is not supported by Vercel Serverless Functions.\n` +
				`\tYour project will use Node.js 24 as the runtime instead.\n` +
				`\tConsider switching your local version to 24.\n`,
		);
		return 'nodejs24.x';
	}
	if (support.status === 'default' || support.status === 'available') {
		return `nodejs${major}.x`;
	}
	if (support.status === 'retiring') {
		if (support.warnDate && new Date() >= support.warnDate) {
			logger.warn(
				`Your project is being built for Node.js ${major} as the runtime, which is retiring by ${support.removal}.`,
			);
		}
		return `nodejs${major}.x`;
	}

View on GitHub (pinned to 3578d45d34)

Solutions

1. Switch the build environment to Node 24 (matching the fallback runtime): use a .nvmrc / .node-version file with '24' or update the CI image (e.g. actions/setup-node with node-version: 24).
2. Upgrade @astrojs/vercel if a newer release added support for your Node major.
3. Pin engines.node in package.json (e.g. ">=24") so the toolchain fails loudly instead of silently deploying a different runtime.
4. Rebuild; the warning disappears and local and deployed runtimes match.

Example fix

# before
# .nvmrc
20.11.0

# after
# .nvmrc
24

const major = Number(process.versions.node.split('.')[0]);
const SUPPORTED = [20, 22, 24]; // keep in sync with @astrojs/vercel
if (!SUPPORTED.includes(major)) {
  throw new Error(
    `Node ${major} is not a supported Vercel serverless runtime; switch to 24 or update @astrojs/vercel`,
  );
}

When it happens

Trigger: Running astro build with the Vercel adapter on a Node major absent from SUPPORTED_NODE_VERSIONS (for example Node 21 or a newly released major not yet added to the adapter). support === undefined, the warning prints, and getRuntime returns 'nodejs24.x'.

Common situations: CI images or local toolchains pinned to non-LTS or bleeding-edge Node; building in Docker with an exotic Node tag; after Vercel drops an old major (e.g. 16/18) from the support table, older build images start hitting this; version-dependent dependencies (native modules, Intl behavior) behaving differently locally vs deployed.

Related errors

• Error generating redirects: ${error.message}
• Error generating routes: ${normalized.error.message}
• Your project is being built for Node.js ${major} as the runt
• Your project is being built for Node.js ${major} as the runt
• Your project is being built for Node.js ${major} as the ru

AI-assisted analysis of withastro/astro@3578d45d34 (2026-08-18). Data as JSON: /api/errors/b3f0d993c8d627fc. Report an issue: GitHub.