What are the differences between Puppeteer's headless and headful modes? When should each be used?

Puppeteer's headless and headful modes are two different browser running methods, each with its own use cases.

Headless Mode:

Headless mode is Puppeteer's default mode, where the browser runs without a graphical interface.

Features:

• No browser window displayed, all operations run in the background
• Consumes fewer system resources, runs faster
• Suitable for server environments and automation tasks
• No display support required

Enable:

javascript
const browser = await puppeteer.launch({
  headless: true  // Default value, can be omitted
});

Use Cases:

• Automated testing in CI/CD pipelines
• Server-side web scraping
• Batch screenshots and PDF generation
• Performance testing and monitoring
• Scheduled tasks and background processing

Headful Mode:

Headful mode displays the full browser interface, allowing users to see all operations.

Features:

• Displays complete browser window
• Can observe browser behavior in real-time
• Easier for debugging and development
• Consumes more system resources

Enable:

javascript
const browser = await puppeteer.launch({
  headless: false
});

Use Cases:

• Development and debugging phase
• Scenarios requiring visual operations
• Demonstrations and teaching
• Manual testing assistance
• Debugging complex interactions

Performance Comparison:

Metric	Headless Mode	Headful Mode
Memory Usage	Lower	Higher
Startup Speed	Fast	Slow
CPU Usage	Low	High
Debugging Difficulty	Higher	Lower
Suitable Environment	Server	Dev Machine

Best Practices:

1. Development Phase: Use headful mode for debugging
2. Testing Environment: Use headless mode for efficiency
3. Production Environment: Always use headless mode
4. Mixed Usage: Dynamically switch modes as needed

Example Code:

javascript
const puppeteer = require('puppeteer');

// Choose mode based on environment variable
const isDev = process.env.NODE_ENV === 'development';

const browser = await puppeteer.launch({
  headless: !isDev,
  devtools: isDev  // Open DevTools in development mode
});