vercel/next.js · error · Error

Invalid URL

Error message

Invalid URL

What it means

Minimal input guard in prepareAppPage (app-render.tsx): before parsing, the incoming request is checked for a URL and req.url is falsy. App Router rendering needs a relative URL to parse into route params and search params; with none present this sentinel error fires — the fault is the malformed/incomplete request object handed to the renderer, not user code.

Source

Thrown at packages/next/src/server/app-render/app-render.tsx:3309

  serverComponentsHmrCache: ServerComponentsHmrCache | undefined,
  sharedContext: AppSharedContext
) => Promise<RenderResult<AppPageRenderResultMetadata>>

type AppPagePreparation = {
  url: ReturnType<typeof parseRelativeUrl>
  parsedRequestHeaders: ParsedRequestHeaders
  interpolatedParams: Params
  postponedState: PostponedState | null
}

function prepareAppPage(
  req: BaseNextRequest,
  pagePath: string,
  fallbackRouteParams: OpaqueFallbackRouteParams | null,
  renderOpts: RenderOpts
): AppPagePreparation {
  if (!req.url) {
    throw new Error('Invalid URL')
  }

  const url = parseRelativeUrl(req.url, undefined, false)

  // We read these values from the request object as, in certain cases,
  // base-server will strip them to opt into different rendering behavior.
  const parsedRequestHeaders = parseRequestHeaders(req.headers, {
    isRoutePPREnabled: renderOpts.experimental.isRoutePPREnabled === true,
    previewModeId: renderOpts.previewProps?.previewModeId,
  })

  const interpolatedParams = interpolateParallelRouteParams(
    renderOpts.ComponentMod.routeModule.userland.loaderTree,
    renderOpts.params ?? {},
    pagePath,
    fallbackRouteParams
  )

View on GitHub (pinned to 258b1c1bc0)

Solutions

1. Check the URL being parsed in your page/middleware; ensure it is an absolute, well-formed URL string.
2. Wrap `new URL(...)` input with a base URL (e.g. `new URL(path, 'http://localhost')`) when the input may be relative.

When it happens

Trigger: Thrown at packages/next/src/server/app-render/app-render.tsx:3276 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of vercel/next.js@258b1c1bc0 (2026-08-19). Data as JSON: /api/errors/cea191f4b96c895c. Report an issue: GitHub.