vercel/next.js · error · Error

"${getDisplayName(App)}.getInitialProps()" is defined as an

Error message

"${getDisplayName(App)}.getInitialProps()" is defined as an instance method - visit https://nextjs.org/docs/messages/get-initial-props-as-an-instance-method for more information.

What it means

Error ""${getDisplayName(App)}.getInitialProps()" is defined as an instance method - visit https://nextjs.org/docs/messages/get-initial-props-as-an-instance-method for more information." thrown in vercel/next.js.

Source

Thrown at packages/next/src/shared/lib/utils.ts:383

      // first we replace any non-encoded backslashes with forward
      // then normalize repeated forward slashes
      .replace(/\\/g, '/')
      .replace(/\/\/+/g, '/') +
    (urlParts[1] ? `?${urlParts.slice(1).join('?')}` : '')
  )
}

export async function loadGetInitialProps<
  C extends BaseContext,
  IP = {},
  P = {},
>(App: NextComponentType<C, IP, P>, ctx: C): Promise<IP> {
  if (process.env.NODE_ENV !== 'production') {
    if (App.prototype?.getInitialProps) {
      const message = `"${getDisplayName(
        App
      )}.getInitialProps()" is defined as an instance method - visit https://nextjs.org/docs/messages/get-initial-props-as-an-instance-method for more information.`
      throw new Error(message)
    }
  }
  // when called from _app `ctx` is nested in `ctx`
  const res = ctx.res || (ctx.ctx && ctx.ctx.res)

  if (!App.getInitialProps) {
    if (ctx.ctx && ctx.Component) {
      // @ts-ignore pageProps default
      return {
        pageProps: await loadGetInitialProps(ctx.Component, ctx.ctx),
      }
    }
    return {} as IP
  }

  const props = await App.getInitialProps(ctx)

  if (res && isResSent(res)) {

View on GitHub (pinned to 89d017eac4)

Solutions

1. Define getInitialProps as a static method on the App component, not an instance method.

When it happens

Trigger: getInitialProps is defined as an instance method on App or a page component.

Common situations: Defining getInitialProps() inside a class body instead of as a static method.

AI-assisted analysis of vercel/next.js@89d017eac4 (2026-08-19). Data as JSON: /api/errors/1fa252e39d23f305. Report an issue: GitHub.