External ID is a unique user identifier that is generated for logged-in users – usually based on their email address.
While the users are logged-in, this ID is sent to Meta with every event that Meta Pixel tracks, e.g. page view, click, form submission or a purchase.
This improves:
- Event Match Quality scores in Meta’s Event Manager,
- cross-browser tracking,
- and conversion attribution.
However, there is a problem – it only works if a user is logged in.
But there is a solution.
How Advanced External ID works in WP Full Picture
Advanced External ID improves on the standard mechanism in 2 areas:
- It is remembered after a user logs out. This way, it can be sent with events generated by logged-out users.
- It can be generated based on an email address that a user leaves in a form on a website. A user doesn’t have to be logged-in for this to happen. The ID is generated using a one-way encoding method and cannot be “reverse engineered” to get the email address.
As a result, more events can get External ID and improve conversion attribution and Event Match Quality scores.
No privacy issues
We generate and store (in a browser cookie and local storage) external IDs only for visitors who agree to using their data for marketing. No data is stored otherwise.
How to turn on Advanced External ID
- Go to the settings of the Meta Pixel module
- Click “Data collection settings” in the left menu
- Enable “Advanced Matching” – this will enable saving External ID in a cookie after a user logs out
- In the field below it, provide CSS selectors of form fields, where users leave their email addresses.