playwright/docs/src/library-js.md

---
id: library
title: "Library"
---

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](./intro.md).

## 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:


```js tab=js-ts
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();
})();
```

```js tab=js-js
const assert = require('node:assert');
const { chromium, devices } = require('playwright');

(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:

```js tab=js-ts
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');
});
```

```js tab=js-js
const { expect, test, devices } = require('@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:

| | Library | Test |
| - | - | - |
| Installation | `npm install playwright` | `npm init playwright@latest` - note `install` vs. `init` |
| Install browsers | Chromium, Firefox, WebKit are installed by default | `npx playwright install` or `npx playwright install chromium` for a single one |
| `import`/`require` name | `playwright` | `@playwright/test` |
| Initialization | Explicitly need to: <ol><li>Pick a browser to use, e.g. `chromium`</li><li>Launch browser with [`method: BrowserType.launch`]</li><li>Create a context with [`method: Browser.newContext`], <em>and</em> pass any context options explicitly, e.g. `devices['iPhone 11']`</li><li>Create a page with [`method: BrowserContext.newPage`]</li></ol> | An isolated `page` and `context` are provided to each test out-of the box, along with other [built-in fixtures](./test-fixtures.md#built-in-fixtures). No explicit creation. If referenced by the test in it's arguments, the Test Runner will create them for the test. (i.e. lazy-initialization) |
| Assertions | No built-in Web-First Assertions | [Web-First assertions](./test-assertions.md) like: <ul><li>[`method: PageAssertions.toHaveTitle`]</li><li>[`method: PageAssertions.toHaveScreenshot#1`]</li></ul> which auto-wait and retry for the condition to be met.|
| Cleanup | Explicitly need to: <ol><li>Close context with [`method: BrowserContext.close`]</li><li>Close browser with [`method: Browser.close`]</li></ol> | No explicit close of [built-in fixtures](./test-fixtures.md#built-in-fixtures); the Test Runner will take care of it.
| Running | When 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](./test-configuration.md), 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:

- [Configuration Matrix and Projects](./test-configuration.md): In the above example, in the Playwright Library version, if we wanted to run with a different device or browser, we'd have to modify the script and plumb the information through. With Playwright Test, we can just specify the [matrix of configurations](./test-configuration.md) in one place, and it will create run the one test under each of these configurations.
- [Parallelization](./test-parallel.md)
- [Web-First Assertions](./test-assertions.md)
- [Reporting](./test-reporters.md)
- [Retries](./test-retries.md)
- [Easily Enabled Tracing](./trace-viewer-intro.md)
- and more…

## Usage

Use npm or Yarn to install Playwright library in your Node.js project. See [system requirements](./intro.md#system-requirements).

```bash
npm i -D playwright
```

This single command downloads the Playwright NPM package and browser binaries for Chromium, Firefox and WebKit. To modify this behavior see [managing browsers](./browsers.md#managing-browser-binaries).

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

```js
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](https://developer.mozilla.org/en-US/docs/Learn/JavaScript/Asynchronous/Async_await) to ease readability. The code is wrapped in an unnamed async arrow function which is invoking itself.

```js
(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.

```js
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](./debug.md).

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

## Record scripts

[Command line tools](./test-cli.md) can be used to record user interactions and generate JavaScript code.

```bash
npx playwright codegen wikipedia.org
```

## Browser downloads

By default, `playwright` automatically downloads Chromium, Firefox and WebKit during package installation.

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.

```bash tab=bash-bash lang=js
PLAYWRIGHT_SKIP_BROWSER_DOWNLOAD=1 npm install
```

```batch tab=bash-batch lang=js
set PLAYWRIGHT_SKIP_BROWSER_DOWNLOAD=1
npm install
```

```powershell tab=bash-powershell lang=js
$Env: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.

```js
// @ts-check
// ...
```

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

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

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

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