The answer depends on where you're building and using the audience. Here's how it works on Meta (Facebook/Instagram):
Custom audiences from product views (Website Custom Audiences via Pixel or CAPI):
These audiences do auto-refresh, but not in true real-time.
Facebook updates them approximately every few hours, with most updates completed within 24 hours.
So while it's close to real-time, there can be a slight delay (usually 1–4 hours depending on volume and traffic).
This means:
If someone views a product, they’ll usually be added to your retargeting audience the same day, but not instantly.
Meta queues and processes events in batches, not in real-time like a CRM might.
Pro tip:
If you're running time-sensitive ads (like cart abandonment retargeting within 1 hour), that slight lag can matter — in which case using event-based triggers via 3rd-party tools or CRM-integrated audiences (like Klaviyo + Meta) can help create more immediate syncing.
