Skip to main content

Library

Introduction​

Playwright Library provides unified APIs for launching and interacting with browsers, while Playwright Test provides all this plus a fully managed end-to-end Test Runner and experience.

Under most circumstances, for end-to-end testing, you'll want to use @playwright/test (Playwright Test), and not playwright (Playwright Library) directly. To get started with Playwright Test, follow the Getting Started Guide.

Differences when using library​

Library Example​

The following is an example of using the Playwright Library directly to launch Chromium, go to a page, and check its title:

import { chromium, devices } from 'playwright';
import assert from 'node:assert';

(async () => {
  // Setup
  const browser = await chromium.launch();
  const context = await browser.newContext(devices['iPhone 11']);
  const page = await context.newPage();

  // The actual interesting bit
  await context.route('**.jpg', route => route.abort());
  await page.goto('https://example.com/');

  assert(await page.title() === 'Example Domain'); // 👎 not a Web First assertion

  // Teardown
  await context.close();
  await browser.close();
})();

Run it with node my-script.js.

Test Example​

A test to achieve similar behavior, would look like:

import { expect, test, devices } from '@playwright/test';

test.use(devices['iPhone 11']);

test('should be titled', async ({ page, context }) => {
  await context.route('**.jpg', route => route.abort());
  await page.goto('https://example.com/');

  await expect(page).toHaveTitle('Example');
});

Run it with npx playwright test.

Key Differences​

The key differences to note are as follows:

LibraryTest
Installationnpm install playwrightnpm init playwright@latest - note install vs. init
Install browsersInstall @playwright/browser-chromium, @playwright/browser-firefox and/or @playwright/browser-webkitnpx playwright install or npx playwright install chromium for a single one
import fromplaywright@playwright/test
InitializationExplicitly need to:
  1. Pick a browser to use, e.g. chromium
  2. Launch browser with browserType.launch()
  3. Create a context with browser.newContext(), and pass any context options explicitly, e.g. devices['iPhone 11']
  4. Create a page with browserContext.newPage()
An isolated page and context are provided to each test out-of the box, along with other built-in fixtures. No explicit creation. If referenced by the test in its arguments, the Test Runner will create them for the test. (i.e. lazy-initialization)
AssertionsNo built-in Web-First AssertionsWeb-First assertions like: which auto-wait and retry for the condition to be met.
TimeoutsDefaults to 30s for most operations.Most operations don't time out, but every test has a timeout that makes it fail (30s by default).
CleanupExplicitly need to:
  1. Close context with browserContext.close()
  2. Close browser with browser.close()
No explicit close of built-in fixtures; the Test Runner will take care of it.
RunningWhen using the Library, you run the code as a node script, possibly with some compilation first.When using the Test Runner, you use the npx playwright test command. Along with your config, the Test Runner handles any compilation and choosing what to run and how to run it.

In addition to the above, Playwright Test, as a full-featured Test Runner, includes:

Usage​

Use npm or Yarn to install Playwright library in your Node.js project. See system requirements.

npm i -D playwright

You will also need to install browsers - either manually or by adding a package that will do it for you automatically.

# Download the Chromium, Firefox and WebKit browser
npx playwright install chromium firefox webkit

# Alternatively, add packages that will download a browser upon npm install
npm i -D @playwright/browser-chromium @playwright/browser-firefox @playwright/browser-webkit

See managing browsers for more options.

Once installed, you can import Playwright in a Node.js script, and launch any of the 3 browsers (chromium, firefox and webkit).

const { chromium } = require('playwright');

(async () => {
  const browser = await chromium.launch();
  // Create pages, interact with UI elements, assert values
  await browser.close();
})();

Playwright APIs are asynchronous and return Promise objects. Our code examples use the async/await pattern to ease readability. The code is wrapped in an unnamed async arrow function which is invoking itself.

(async () => { // Start of async arrow function
  // Function code
  // ...
})(); // End of the function and () to invoke itself

First script​

In our first script, we will navigate to https://playwright.dev/ and take a screenshot in WebKit.

const { webkit } = require('playwright');

(async () => {
  const browser = await webkit.launch();
  const page = await browser.newPage();
  await page.goto('https://playwright.dev/');
  await page.screenshot({ path: `example.png` });
  await browser.close();
})();

By default, Playwright runs the browsers in headless mode. To see the browser UI, pass the headless: false flag while launching the browser. You can also use slowMo to slow down execution. Learn more in the debugging tools section.

firefox.launch({ headless: false, slowMo: 50 });

Record scripts​

Command line tools can be used to record user interactions and generate JavaScript code.

npx playwright codegen wikipedia.org

Browser downloads​

To download Playwright browsers run:

# Explicitly download browsers
npx playwright install

Alternatively, you can add @playwright/browser-chromium, @playwright/browser-firefox and @playwright/browser-webkit packages to automatically download the respective browser during the package installation.

# Use a helper package that downloads a browser on npm install
npm install @playwright/browser-chromium

Download behind a firewall or a proxy

Pass HTTPS_PROXY environment variable to download through a proxy.

# Manual
HTTPS_PROXY=https://192.0.2.1 npx playwright install

# Through @playwright/browser-chromium, @playwright/browser-firefox
# and @playwright/browser-webkit helper packages
HTTPS_PROXY=https://192.0.2.1 npm install

Download from artifact repository

By default, Playwright downloads browsers from Microsoft's CDN. Pass PLAYWRIGHT_DOWNLOAD_HOST environment variable to download from an internal artifacts repository instead.

# Manual
PLAYWRIGHT_DOWNLOAD_HOST=192.0.2.1 npx playwright install

# Through @playwright/browser-chromium, @playwright/browser-firefox
# and @playwright/browser-webkit helper packages
PLAYWRIGHT_DOWNLOAD_HOST=192.0.2.1 npm install

Skip browser download

In certain cases, it is desired to avoid browser downloads altogether because browser binaries are managed separately. This can be done by setting PLAYWRIGHT_SKIP_BROWSER_DOWNLOAD variable before installing packages.

# When using @playwright/browser-chromium, @playwright/browser-firefox
# and @playwright/browser-webkit helper packages
PLAYWRIGHT_SKIP_BROWSER_DOWNLOAD=1 npm install

TypeScript support​

Playwright includes built-in support for TypeScript. Type definitions will be imported automatically. It is recommended to use type-checking to improve the IDE experience.

In JavaScript​

Add the following to the top of your JavaScript file to get type-checking in VS Code or WebStorm.

// @ts-check
// ...

Alternatively, you can use JSDoc to set types for variables.

/** @type {import('playwright').Page} */
let page;

In TypeScript​

TypeScript support will work out-of-the-box. Types can also be imported explicitly.

let page: import('playwright').Page;