microsoft/playwright · error · Error

Launching server is not supported

Error message

Launching server is not supported

What it means

Thrown by BrowserType.launchServer() when _serverLauncher is undefined. The server launcher is only attached on full Playwright builds; thin/remote clients and some embedded distributions don't provide it. The guard `!this._serverLauncher` rejects the call before delegating.

Source

Thrown at packages/playwright-core/src/client/browserType.ts:87

    const logger = options.logger || this._playwright._defaultLaunchOptions?.logger;
    options = { ...this._playwright._defaultLaunchOptions, ...options };
    const launchOptions: channels.BrowserTypeLaunchParams = {
      ...options,
      ignoreDefaultArgs: Array.isArray(options.ignoreDefaultArgs) ? options.ignoreDefaultArgs : undefined,
      ignoreAllDefaultArgs: !!options.ignoreDefaultArgs && !Array.isArray(options.ignoreDefaultArgs),
      env: options.env ? envObjectToArray(options.env) : undefined,
    };
    return await this._wrapApiCall(async () => {
      const browser = Browser.from((await this._channel.launch(launchOptions, new TimeoutSettings().launchTimeout(options))).browser);
      browser._connectToBrowserType(this, options, logger);
      return browser;
    });
  }

  async launchServer(options: LaunchServerOptions = {}): Promise<api.BrowserServer> {
    if (!this._serverLauncher)
      throw new Error('Launching server is not supported');
    options = { ...this._playwright._defaultLaunchOptions, ...options };
    return await this._serverLauncher.launchServer(options);
  }

  async launchPersistentContext(userDataDir: string, options: LaunchPersistentContextOptions = {}): Promise<BrowserContext> {
    assert(!(options as any).port, 'Cannot specify a port without launching as a server.');
    options = this._playwright.selectors._withSelectorOptions({
      ...this._playwright._defaultLaunchOptions,
      ...options,
    });
    await this._instrumentation.runBeforeCreateBrowserContext(options);

    const logger = options.logger || this._playwright._defaultLaunchOptions?.logger;
    const contextParams = await prepareBrowserContextParams(options);
    const persistentParams: channels.BrowserTypeLaunchPersistentContextParams = {
      ...contextParams,
      ignoreDefaultArgs: Array.isArray(options.ignoreDefaultArgs) ? options.ignoreDefaultArgs : undefined,
      ignoreAllDefaultArgs: !!options.ignoreDefaultArgs && !Array.isArray(options.ignoreDefaultArgs),

View on GitHub (pinned to c8fc3bf8d3)

Solutions

1. Run launchServer from the full `playwright` or `playwright-core` package on the host.
2. Use connect/connectOverCDP from thin clients instead of launching servers.
3. If you must launch remotely, run a full Playwright process on the server host and connect to it.

Example fix

// before (thin client)
const { chromium } = require('@playwright/client');
await chromium.launchServer();
// after
const { chromium } = require('playwright');
await chromium.launchServer();

if (!(browserType as any)._serverLauncher)
  throw new Error('launchServer unavailable in this build; use the full playwright-core package.');

function supportsLaunchServer(bt: any): boolean {
  return !!bt?._serverLauncher;
}

When it happens

Trigger: Calling `chromium.launchServer()` from playwright-client or another thin-client entry, or in an environment where only the connect-side surface is wired. _serverLauncher is set only on the host owning the registry.

Common situations: Using playwright-client expecting full launch capability; bundling a stripped-down Playwright build; calling launchServer in a worker/remote context that only forwards commands.

Related errors

• Launching server is not supported
• No devices found
• No device with serial number '${options.deviceSerialNumber}'
• More than one device found. Please specify deviceSerialNumbe
• Route from har is not supported in thin clients

AI-assisted analysis of microsoft/playwright@c8fc3bf8d3 (2026-08-12). Data as JSON: /api/errors/e84aab3ffeee16bf. Report an issue: GitHub.