Playwright: page.goto: net::ERR_CONNECTION_REFUSED

The hostname resolved, but nothing accepted a TCP connection on that address and port. The operating system answered with a refusal, so the browser reported net::ERR_CONNECTION_REFUSED and Playwright threw from page.goto. In Firefox the equivalent is NS_ERROR_CONNECTION_REFUSED.

In test suites this almost always means the application under test is not running yet, or is listening somewhere other than where the browser is looking. A classic case is localhost inside a Docker container: it refers to the container itself, not the host where your dev server runs. Another is IPv6: Node.js may bind to ::1 while the browser connects to 127.0.0.1, or the reverse.

What is not wrong: DNS and the URL's hostname. Unlike a timeout, a refusal is instant and definite.

// playwright.config.ts
import { defineConfig } from '@playwright/test';

export default defineConfig({
  webServer: {
    command: 'npm run start',
    url: 'http://127.0.0.1:3000',
    reuseExistingServer: !process.env.CI,
    timeout: 120_000,
  },
  use: { baseURL: 'http://127.0.0.1:3000' },
});

Never rely on a fixed sleep for server startup; use the webServer option or a readiness probe that polls the URL. Use explicit 127.0.0.1 in both the server bind and the base URL to avoid address-family surprises. In containerized setups, document which hostname the browser should use and set it through one environment variable.