Audience & TargetingCustom Audience
What is a Custom Audience? How It Works and How to Build One
Also known as: custom audiences
Short answer
A Custom Audience is an ad audience built from your own data, such as a customer list, website visitors, or people who messaged you. The ad platform matches that data against its users, then your ad shows only to people on the list.
The simple way to think about it
A Custom Audience is a guest list. You hand the door a list of names, and only people on that list see your ad.
The most useful sources
| Source | Main use |
|---|---|
| Website visitors | General retargeting |
| Conversion events you send | A sharp BoF audience |
| Buyer lists | Exclusion and cross-selling |
| People who messaged | Following up a stalled chat |
| Video viewers | A MoF audience |
Rules worth keeping
- Send tidy values. Phone numbers with a country code, emails without spaces or capitals.
- Never send values already encrypted inside your own system as identifiers. What the ad platform needs is a standard one-way code, not internal ciphertext.
- Hold a lawful basis for using that data, and honour deletion requests from customers.
Frequently asked questions
- Where can Custom Audience data come from?
- From website visitors recorded by your tracking code, from events you send to the ad platform, from customer lists you upload, and from in-platform interactions such as video views or inbound messages.
- Does the ad platform see my customers phone numbers?
- Identifiers such as email and phone are turned into one-way codes before they are sent, so what gets compared is the code, not the original value. Matching still works because both sides compute the code the same way.
- Why is the matched count smaller than my list?
- Because not every contact uses that platform, and some signed up with a different email or number. Match rates rise when phone and email formats are cleaned first.
Related terms
Konektor guides
Your ad numbers are only as accurate as the data behind them
Konektor captures the Click ID and sends conversions that close on WhatsApp, over the phone, or in a shop back to the ad platform.