vitest-dev/vitest · error · Error

Can't find browser origin URL for project

Error message

Can't find browser origin URL for project "${this.name}"

What it means

After confirming the browser is initialized, _openBrowserPage reads this.browser.vite.resolvedUrls to find the local or network origin. If neither local[0] nor network[0] exists, there is no URL to build the test page address from, so it throws naming the project.

Solutions

1. Check the Vite dev server startup logs for bind/listen errors.
2. Ensure server.host/port config is valid and the port is not already in use.
3. Avoid custom plugins that override resolvedUrls or server.listen behavior.
4. Retry after the server is fully ready; if persistent, file an issue with the server config.

// Ensure the dev server produced URLs before opening pages.
function assertOrigin(urls: { local?: string[]; network?: string[] } | null | undefined) {
  const origin = urls?.local?.[0] ?? urls?.network?.[0]
  if (!origin) throw new Error('Browser dev server has no resolved URL; check server config / port.')
  return origin
}

const hasResolvedUrl = (urls: { local?: string[]; network?: string[] } | null | undefined): boolean =>
  Boolean(urls && (urls.local?.length || urls.network?.length))

When it happens

Trigger: The browser Vite server has no resolvedUrls (local/network both empty) when _openBrowserPage tries to construct the /__vitest_test__/ page URL.

Common situations: The dev server failed to bind/resolve URLs, a custom server config that suppresses resolvedUrls, the server starting in a mode that does not compute URLs, or a race reading resolvedUrls before server.listen finished.

Related errors

• Browser is not initialized
• browser is not initialized
• Cannot spawn child server without a parent dev server.
• Access denied to " ". See Vite config documentation for…
• All browser instances within a project must use the same…

AI-assisted analysis of vitest-dev/vitest@1fa9837ec2 (2026-08-11). Data as JSON: /api/errors/7e3aa7aa474873a1. Report an issue: GitHub.

Appendix: source

Thrown at packages/vitest/src/node/project.ts:484

  /** @internal */
  public _getViteEnvironments(): DevEnvironment[] {
    return Object.values(this.vite.environments || {})
  }

  /** @internal */
  public async _openBrowserPage(sessionId: string, pool: {
    reject: (error: Error) => void
    parallel?: boolean
  }): Promise<void> {
    if (!this.browser) {
      throw new Error(`browser is not initialized`)
    }

    const resolvedUrls = this.browser.vite.resolvedUrls
    const origin = resolvedUrls?.local[0] ?? resolvedUrls?.network[0]
    if (!origin) {
      throw new Error(
        `Can't find browser origin URL for project "${this.name}"`,
      )
    }

    const url = new URL('/__vitest_test__/', origin)
    url.searchParams.set('sessionId', sessionId)
    const otelCarrier = this.vitest._traces.getContextCarrier()
    this.vitest._browserSessions.sessionIds.add(sessionId)
    const sessionPromise = this.vitest._browserSessions.createSession(
      sessionId,
      this,
      pool,
      { otelCarrier },
    )
    const pagePromise = this.browser.provider.openPage(
      sessionId,
      url.toString(),
      { parallel: pool.parallel ?? false },

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