What are the recommended parameters to send to Meta when sending user data?
In addition to the required event parameters, Meta strongly recommends sending user data parameters. These fields help Meta improve attribution and campaign performance by increasing the likelihood of matching an event to the correct person.
How Does Meta Use User Data for Matching Events?
When someone interacts with your ad and later completes an action on your website, Meta attempts to connect the two actions. User data parameters provide identifying details that make this connection more accurate. The stronger the match, the better Meta can:
Attribute conversions back to the right ad.
Optimize delivery toward people most likely to convert.
Build higher-quality custom audiences and lookalikes.
Key Recommended Fields
em (Email)
The user’s email address.
One of the strongest identifiers because most people use the same email across accounts.
ph (Phone Number)
The user’s phone number in international format.
Another highly reliable identifier, especially for leads and registrations.
fn (First Name) and ln (Last Name)
The user’s first and last name.
Useful when combined with other identifiers such as email or phone.
external_id
A unique ID from your system, such as a customer ID or CRM identifier.
This allows you to match events back to individual records in your own database.
IP Address and User Agent
Captured automatically in most cases.
Helps confirm device and location information, adding another layer of matching accuracy.
How Does PixelFlow Handle Sensitive User Data?
PixelFlow automatically hashes sensitive user data before sending it to Meta. Hashing is a one-way process that converts identifiers like emails and phone numbers into a secure format. Meta then compares the hashed values with its own records to find matches. This means:
Raw data never leaves your system.
Sensitive fields remain protected while still enabling accurate event matching.