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Uploading a customer list to Meta is one of the best ways to reach people who already know you on Facebook and Instagram. But Meta can only use the numbers it can match to an account, and many lists match worse than expected. Checking the list first tells you what you are working with before you build audiences and spend budget
How customer list audiences work
In Meta Ads Manager you can create a Custom Audience from a customer list: a file with phone numbers, email addresses or other details of your customers. Meta compares the list with its users and builds an audience from the people it finds. Before the file leaves your computer, Ads Manager turns each value into a hash, a scrambled code, so the raw numbers are not sent as they are
From that audience you can:
- show ads to your existing customers, or exclude them
- build a Lookalike Audience: people who are similar to your customers. The source needs at least 100 people from one country
Why lists match badly
The most common reasons a list matches poorly:
- Wrong format. Meta asks for phone numbers with the country code. Numbers that start with 0, or that Excel turned into
4.91512E+12, cannot be matched. Our guide to international format shows the right way for 20 countries - Numbers without an account. Old numbers, landlines and numbers of people who do not use Facebook or Instagram
- Duplicates and junk. They make the list look bigger than it is
Check the list before you upload it
With the Facebook Checker and the Instagram Checker on PWF Platform you find out which numbers in your list are linked to an account on each platform. You upload the list once per check and get two files back: registered and not registered
That helps you to:
- Know your real audience size before you pay for a list or plan a campaign around it
- Build a cleaner source for lookalike audiences from numbers that are linked to accounts
- Choose the platform. A list with many Instagram accounts and few Facebook accounts calls for a different plan than the other way round
Get the file ready
- Put every number in international format, with the country code and no 0 after it
- Remove duplicates after formatting, so
0151…and+49 151…count once - Keep one country per file. Our checks work one country per order, and a lookalike source needs at least 100 people from one country anyway
- Upload the
.txtor.csvfile, one number per line
What the result means
A number marked as registered is linked to an account on that platform at the time of the check. That makes it more likely to be found when you upload it to Meta, but Meta does the final match and decides who ends up in your audience
Permission comes first
Meta's terms for customer lists require that you are allowed to use the data in this way, and privacy laws like the GDPR ask the same. Only upload lists of people who gave you their details and agreed to hear from you, and remove anyone who opted out
