Implementation:Getgauge Taiko OpenBrowser

Knowledge Sources	Taiko
Domains	Browser_Automation, Testing
Last Updated	2026-02-12 00:00 GMT

Overview

Concrete tool for launching a Chromium browser instance and establishing a Chrome DevTools Protocol (CDP) connection, provided by the Taiko library.

Description

openBrowser is the foundational function in every Taiko automation script. It launches a Chromium process (either headless or headful), connects to it via the Chrome DevTools Protocol (CDP) WebSocket interface, and initializes all CDP domain handlers required for subsequent browser interactions.

Key behaviors include:

Headless by default — the browser runs without a visible UI unless headless: false is specified.
Automatic port selection — when port is 0 (the default), a random available port is chosen for the CDP debugging connection.
Observe mode — when observe: true, Taiko runs in slow-motion mode with configurable delays between actions, useful for visual debugging and demonstrations.
Docker-safe flags — supports Chromium launch arguments commonly needed in containerized environments (e.g., --no-sandbox, --disable-dev-shm-usage).
Certificate handling — by default, certificate errors are ignored (ignoreCertificateErrors: true), simplifying testing against self-signed or development certificates.

Usage

Call openBrowser() at the beginning of every Taiko automation script or REPL session. It must be called before any navigation or interaction functions like goto, click, or write. The browser remains open until closeBrowser() is explicitly called.

Code Reference

Source Location

Repository: Taiko
File: lib/taiko.js
Lines: L90-125

Signature

module.exports.openBrowser = async (options = { headless: true }) => { ... }

Import

const { openBrowser } = require('taiko');

I/O Contract

Inputs

Name	Type	Required	Default	Description
options	Object	No	`{ headless: true }`	Configuration object for browser launch and CDP connection.
options.headless	boolean	No	`true`	Whether to launch Chromium in headless mode (no visible UI) or headful mode (visible browser window).
options.args	string[]	No	`[]`	Additional Chromium command-line launch flags (e.g., `--window-size=1440,900`, `--no-sandbox`).
options.host	string	No	`'127.0.0.1'`	Hostname or IP address for the remote debugging connection.
options.port	number	No	`0`	Remote debugging port. A value of `0` selects a random available port.
options.target	string	No	—	Specific target for the chrome-remote-interface connection.
options.useHostName	boolean	No	`false`	When `true`, uses the hostname instead of the IP address for the CDP connection.
options.secure	boolean	No	`false`	When `true`, uses HTTPS/WSS for the CDP frontend connection.
options.ignoreCertificateErrors	boolean	No	`true`	When `true`, ignores SSL/TLS certificate errors during navigation.
options.observe	boolean	No	`false`	When `true`, enables slow-motion observe mode for visual debugging.
options.observeTime	number	No	`3000`	Delay in milliseconds between actions when observe mode is enabled.
options.dumpio	boolean	No	`false`	When `true`, dumps browser process stdout and stderr to the Node.js process.

Outputs

Name	Type	Description
(return)	Promise<void>	Resolves when the browser is fully launched and the CDP connection is established with all domain handlers initialized. No explicit return value.

Side Effects

A Chromium process is spawned as a child process.
A CDP WebSocket connection is established to the browser's debugging port.
All CDP domain handlers (Page, Network, Runtime, DOM, etc.) are initialized and ready for use.
Internal Taiko state is updated to track the active browser connection.

Dependencies

chrome-remote-interface — provides the CDP WebSocket client for communicating with Chromium
Chromium binary — the actual browser executable (bundled or system-installed)

Usage Examples

Default Headless

const { openBrowser, goto, closeBrowser } = require('taiko');

(async () => {
  try {
    await openBrowser();
    await goto('https://example.com');
  } finally {
    await closeBrowser();
  }
})();

Headful for Debugging

await openBrowser({ headless: false });

Custom Window Size

await openBrowser({ args: ['--window-size=1440,900'] });

Observe Mode

await openBrowser({ headless: false, observe: true, observeTime: 2000 });

Docker-Safe Configuration

await openBrowser({
  args: [
    '--disable-gpu',
    '--disable-dev-shm-usage',
    '--disable-setuid-sandbox',
    '--no-first-run',
    '--no-sandbox',
    '--no-zygote'
  ]
});

Related Pages

Implements Principle

Principle:Getgauge_Taiko_Browser_Launch

Requires Environment

Uses Heuristic

Page Connections

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Implementation

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Environment