Meta Custom Audience Formatter

Why Formatted Lists Match Better on Meta

When advertisers upload offline conversion sheets or customer lists to Meta, the platform does not read the raw emails or phone numbers. Instead, Meta hashes the data using the SHA-256 algorithm to create localized, irreversible keys, and compares those hashes with their internal user database records.

If customer emails contain spaces, upper case letters, or periods inside Gmail addresses, the compiled SHA-256 hash will be completely different from Meta's database version, preventing match attributions. Pre-formatting and cleaning lists with standard formatting rules ensures your records map accurately.

Important Formatting Guidelines

• Email Formatting: Email addresses must be strictly lowercased, with trailing and leading whitespace trimmed. Spaces inside address names must be stripped out entirely.
• Phone Formatting: Phone numbers must contain country codes and contain zero leading zeros, symbols, spaces, or dashes. If customer spreadsheets only list raw local numbers, our formatter will auto-prepend the selected country code to boost match precision.
• Local Shield Privacy: Never upload customer list data into online external servers that store copy-pasted details. Protecting customer lists prevents security breaches and maintains compliance under GDPR, CCPA, and Meta policies.