Puppeteer Launch Options and Page Request Interception: Ensuring Request Capture Across Navigations

Direct Answers

1. Recommended pattern: Create a helper that calls page.setRequestInterception(true) immediately after newPage() and before any navigation. Use this helper for both regular and incognito pages.
2. Persistence across navigations: Do not disable interception. Leave it enabled for the page's entire lifetime; toggling setRequestInterception(false) resets the flag and creates a race window where early requests slip through.
3. Incognito propagation: There is no documented launch option or context-level flag that propagates interception to incognito pages. Each incognito page must enable interception independently.

Minimal Helper Implementation

async function createInterceptedPage(browserOrContext, handler) {
  const page = await browserOrContext.newPage();
  await page.setRequestInterception(true);
  page.on('request', handler);
  return page;
}

// Regular page
const page = await createInterceptedPage(browser, req => req.continue());

// Incognito page
const incognitoCtx = await browser.createIncognitoBrowserContext();
const incognitoPage = await createInterceptedPage(incognitoCtx, req => req.continue());

Why This Works

Puppeteer's setRequestInterception is a per-page CDP flag. The Chrome DevTools Protocol resets it to false on every navigation (including same-document navigations). The only documented guarantee to capture the very first request is enabling interception before any navigation command (page.goto, page.click on links, page.reload, etc.).

Incognito contexts are fully isolated: they share no cookies, storage, service workers, or interception state with the parent browser context. The helper above ensures each page—regular or incognito—starts with interception active.

Critical Constraints

• No launch option exists. puppeteer.launch({...}) cannot pre-enable interception.
• Never toggle off. If you need to pause processing, use a no-op handler (request.continue()) instead of setRequestInterception(false).
• Enable before triggers. When using page.waitForNavigation() or page.waitForNetworkIdle(), interception must already be active before the action that initiates navigation.
• Cache side-effect. Enabling interception disables the browser cache by default. Newer CDP versions support { interception: true, cacheEnabled: true } (experimental) if cache behavior matters.

Verification Checklist

1. Run a minimal script against your target Chrome/Chromium revision that creates both page types, navigates to https://example.com, and logs every intercepted request URL.
2. Confirm the first request (usually the document) appears for both regular and incognito pages.
3. Check the Puppeteer changelog for your version (npm view puppeteer versions --json) to verify no regression in setRequestInterception persistence.

One Diagnostic Detail

Which Puppeteer version and Chrome/Chromium revision are you deploying against? Behavior can differ across CDP versions, and Firefox (via puppeteer-firefox) has different interception semantics.