sveltejs/kit · error · Error

${keypath} must be a valid origin (e.g. 'https://my-site.com

Error message

${keypath} must be a valid origin (e.g. 'https://my-site.com'). '${input}' could not be parsed as a URL

What it means

`prerender.origin` (validated here) must be a parseable URL, since SvelteKit uses it to resolve absolute URLs during prerendering. If `new URL(input)` throws, the config value is not a valid URL and this error is thrown including the bad input.

Source

Thrown at packages/kit/src/core/config/options.js:225

				if (input.endsWith('/')) {
					throw new Error(
						`${keypath} option must not end with '/'. See https://svelte.dev/docs/kit/configuration#paths`
					);
				}
			}

			return input;
		}),
		origin: validate(undefined, (input, keypath) => {
			assert_string(input, keypath);

			let url;

			try {
				url = new URL(input);
			} catch {
				throw new Error(
					`${keypath} must be a valid origin (e.g. 'https://my-site.com'). '${input}' could not be parsed as a URL`
				);
			}

			if (url.protocol !== 'http:' && url.protocol !== 'https:') {
				throw new Error(
					`${keypath} must be a valid origin — only 'http' and 'https' protocols are supported, received '${url.protocol}'`
				);
			}

			const origin = url.origin;

			if (input !== origin) {
				throw new Error(
					`${keypath} must be a valid origin — received '${input}' which contains a path, query, or hash. Use the bare origin '${origin}' instead`
				);
			}

View on GitHub (pinned to 03f1687fe6)

Solutions

1. Include the full scheme: `https://my-site.com`
2. Verify with `new URL(value)` in Node before assigning
3. If the value comes from an env var, check it is set and non-empty: `origin: process.env.ORIGIN ?? 'https://my-site.com'`
4. Trim whitespace from env-derived values

Example fix

// before
prerender: { origin: 'my-site.com' }
// after
prerender: { origin: 'https://my-site.com' }

const origin = config.prerender?.origin;
if (origin !== undefined) {
  try {
    new URL(origin);
  } catch {
    throw new Error(`prerender.origin is not a valid URL: '${origin}'`);
  }
}

function isParseableUrl(v) {
  if (typeof v !== 'string') return false;
  try {
    new URL(v);
    return true;
  } catch {
    return false;
  }
}

try {
  assertOrigin(config.prerender?.origin);
} catch (e) {
  if (String(e.message).includes('could not be parsed as a URL')) {
    console.error('Include the full scheme, e.g. https://my-site.com');
  }
  throw e;
}

When it happens

Trigger: `prerender: { origin: 'my-site.com' }` (missing scheme) or `origin: 'https'`/`origin: ''` — any string the `URL` constructor cannot parse.

Common situations: Forgetting `https://` in svelte.config.js; env var `ORIGIN` unset so an empty or partial string is used; trailing whitespace or typos in CI-configured origins.

Understand the failure class

Background: "Invalid URL" errors: why new URL(), URI.parse, and reqwest::Url reject your string — missing scheme, whitespace, and bad path format — this error's family across 39 libraries.

Related errors

• ${keypath} should be "fail", "warn", "ignore" or a custom fu
• ${keypath} option must be an absolute path, if specified. Se
• ${keypath} must be a valid origin — only 'http' and 'https'
• Invalid isr.expiration value: ${JSON.stringify(value)} (${de
• The SvelteKit options from the Vite config must be an object

AI-assisted analysis of sveltejs/kit@03f1687fe6 (2026-09-02). Data as JSON: /api/errors/cc283dc2cee74732. Report an issue: GitHub.