Intercept and modify requests

CDP Fetch.enable lets you inspect, block, or modify every request the page makes.

Block by resource type

Puppeteer:

await page.setRequestInterception(true);

page.on('request', req => {
  if (['image', 'media', 'font'].includes(req.resourceType())) {
    req.abort();
  } else {
    req.continue();
  }
});

Playwright:

await page.route('**/*', route => {
  if (['image', 'media', 'font'].includes(route.request().resourceType())) {
    route.abort();
  } else {
    route.continue();
  }
});

Block by URL pattern

// Puppeteer
page.on('request', req => {
  const url = req.url();
  if (url.includes('google-analytics.com') || url.includes('doubleclick.net')) {
    req.abort();
  } else {
    req.continue();
  }
});

// Playwright
await page.route(/google-analytics\.com|doubleclick\.net/, route => route.abort());

Modify headers

// Puppeteer
page.on('request', req => {
  req.continue({
    headers: { ...req.headers(), 'X-Custom': 'value' },
  });
});

// Playwright
await page.route('**/*', route => {
  route.continue({
    headers: { ...route.request().headers(), 'X-Custom': 'value' },
  });
});

Return a fake response

// Puppeteer
page.on('request', req => {
  if (req.url().endsWith('/api/feature-flags')) {
    req.respond({
      status: 200,
      contentType: 'application/json',
      body: JSON.stringify({ newDashboard: true }),
    });
  } else {
    req.continue();
  }
});

// Playwright
await page.route('**/api/feature-flags', route => {
  route.fulfill({
    status: 200,
    contentType: 'application/json',
    body: JSON.stringify({ newDashboard: true }),
  });
});

Strip analytics in production scrapes

const BLOCK = [
  'google-analytics.com',
  'googletagmanager.com',
  'doubleclick.net',
  'facebook.net',
  'segment.io',
  'mixpanel.com',
  'hotjar.com',
];

page.on('request', req => {
  if (BLOCK.some(host => req.url().includes(host))) {
    req.abort();
  } else {
    req.continue();
  }
});

Built-in: --stealth ships with a tracker blocklist that handles most of these without per-script setup. See Configure stealth and proxies.

From the Rust library

The patterns above drive interception over CDP from Puppeteer or Playwright. If you embed the engine with the obscura crate, the same capability is a native API on Page: on_request / on_response callbacks, an enable_interception() channel that can block, mock, or rewrite requests, and add_preload_script to run code before the page's own scripts. See Use as a Rust library.