Playwright Npx

Playwright Browser Automation

🤝 Developed together by Kuba + Mahone · Feb 2026

Code-first browser automation with Playwright.

When to Use

Setup

# One-time per project
npm init -y
npm install playwright
npx playwright install chromium

package.json example:

{
  "name": "my-automation",
  "type": "module",
  "dependencies": {
    "playwright": "^1.40.0"
  }
}

Minimal Example

// tmp/example.mjs
import { chromium } from 'playwright';

const browser = await chromium.launch();
const page = await browser.newPage();

await page.goto('https://example.com');
console.log('Title:', await page.title());

await browser.close();

node tmp/example.mjs

Quick Patterns

Screenshot

import { chromium } from 'playwright';
const browser = await chromium.launch();
const page = await browser.newPage();
await page.setViewportSize({ width: 1280, height: 800 });
await page.goto('https://example.com');
await page.screenshot({ path: 'tmp/screenshot.png', fullPage: true });
await browser.close();

Scrape Data

import { chromium } from 'playwright';
const browser = await chromium.launch();
const page = await browser.newPage();
await page.goto('https://news.ycombinator.com');
const stories = await page.$$eval('.titleline > a', links => 
  links.slice(0, 5).map(a => ({ title: a.innerText, url: a.href }))
);
console.log(JSON.stringify(stories, null, 2));
await browser.close();

Form Interaction

await page.goto('https://example.com/login');
await page.fill('input[name="email"]', 'user@example.com');
await page.fill('input[name="password"]', 'password');
await page.click('button[type="submit"]');

Wait for Dynamic Content

// Wait for network idle (SPA)
await page.goto(url, { waitUntil: 'networkidle' });

// Wait for specific element
await page.waitForSelector('.results', { timeout: 10000 });

// Wait for condition
await page.waitForFunction(() => 
  document.querySelectorAll('.item').length > 0
);

Persistent Session

import fs from 'fs';
const SESSION_FILE = 'tmp/session.json';

let context;
if (fs.existsSync(SESSION_FILE)) {
  context = await browser.newContext({ storageState: SESSION_FILE });
} else {
  context = await browser.newContext();
}
const page = await context.newPage();
// ... login ...
await context.storageState({ path: SESSION_FILE });

Headless vs Headed

// Headless (default, fastest)
await chromium.launch({ headless: true });

// Headed (see the browser)
await chromium.launch({ headless: false });

// Slow motion (debugging)
await chromium.launch({ headless: false, slowMo: 100 });

Selectors Quick Reference

// CSS
await page.click('button.submit');
await page.fill('input#email', 'text');

// Text content
await page.click('text=Submit');
await page.click('text=/log\s*in/i');  // regex

// XPath
await page.click('xpath=//button[@type="submit"]');

// ARIA role
await page.click('role=button[name="Submit"]');

// Test ID (most stable)
await page.click('[data-testid="submit-btn"]');

// Chain selectors
await page.click('nav >> text=Settings');

See references/selectors.md for complete selector guide.

Error Handling

try {
  await page.goto('https://example.com', { timeout: 30000 });
  const hasResults = await page.locator('.results').isVisible().catch(() => false);
  if (!hasResults) {
    console.log('No results');
    process.exit(0);
  }
} catch (error) {
  console.error('Error:', error.message);
  await page.screenshot({ path: 'tmp/error.png' });
  process.exit(1);
} finally {
  await browser.close();
}

Examples & Templates

Working Examples

• examples/screenshot.mjs - Full-page screenshots
• examples/scrape.mjs - Data extraction
• examples/form-interaction.mjs - Form automation
• examples/login-session.mjs - Persistent sessions

Reusable Templates

• scripts/minimal-template.mjs - Clean starting point
• scripts/screenshot-template.mjs - Configurable screenshot
• scripts/scrape-template.mjs - Data scraping scaffold

Copy templates:

cp scripts/minimal-template.mjs tmp/my-task.mjs
# Edit tmp/my-task.mjs, then run:
node tmp/my-task.mjs

Tooling Commands

# Record interactions to generate code
npx playwright codegen https://example.com

# Debug selectors
npx playwright codegen --target javascript https://example.com

# Show trace
npx playwright show-trace tmp/trace.zip

Deep References

• references/selectors.md - Complete selector guide (CSS, text, XPath, ARIA, test-id)
• references/debugging.md - Debugging techniques (headless, slowMo, screenshots)
• references/troubleshooting.md - Common errors and solutions

Tips

• Always put scripts in tmp/ — it's gitignored
• Use .mjs extension for ES modules (no type: module needed)
• Add console.log() liberally for debugging
• Use page.screenshot() when things go wrong
• For complex sites, add await page.waitForLoadState('networkidle')
• See references/debugging.md for detailed debugging guide
• See references/troubleshooting.md for common issues