How does PixelFlow handle Facebook click IDs (fbclid)?

PixelFlow automatically captures and persists the Facebook click ID (fbclid) from your URL parameters to ensure accurate attribution across your entire site, including subdomains and separate app domains.

Multi-stage persistence mechanism

When PixelFlow detects an fbclid parameter in your URL, it generates the _fbc value and stores it using multiple methods:

1. First-party cookie — PixelFlow sets _fbc as a first-party cookie with a 90-day TTL on your root domain (e.g., .yourdomain.com with a leading dot), making it accessible across all subdomains like app.yourdomain.com.

2. Local storage fallback — PixelFlow also stores _fbc to the browser's local storage. If the cookie is blocked, deleted, or unavailable, PixelFlow retrieves the value from local storage.

Works across domain transitions

If URL parameters like fbclid are stripped when users navigate between your main site and app (e.g., from yourdomain.com to app.yourdomain.com), PixelFlow still sends the correct _fbc value to Meta with all subsequent events by pulling it from cookies or local storage.

This ensures consistent attribution even when users move between different parts of your site or when tracking parameters are lost during navigation.