Advertising

Custom Audience

In short

A custom audience is an ad audience made of people who already know you: customer lists, website visitors or people who have engaged with your content.

A custom audience is an ad audience made of people who have already been in touch with your business. You use it to reach these people again, to exclude them from campaigns, or as the source list for a lookalike audience.

Sources for custom audiences

  • Customer list: You upload email addresses or phone numbers. They are made unreadable through hashing before being matched against Meta accounts.
  • Website: Visitors to specific pages, captured through the Meta Pixel or the Conversion API, on Meta for up to 180 days back.
  • App activity: Users who took certain actions in your app.
  • Engagement on Meta: e.g. people who watched a video, opened a lead form or visited your Instagram profile.

Google Ads offers a similar concept for customer lists called Customer Match.

Example

An online course provider has 3,000 leads in the CRM, 400 of whom bought. They create three custom audiences: buyers (to exclude from acquisition campaigns), leads without a purchase (for retargeting with a webinar offer) and visitors to the pricing page in the last 30 days. The retargeting campaign costs $600 and brings in 18 sales from leads that would otherwise have gone cold.

Custom audiences in lead generation

The most valuable custom audiences are built on CRM data: who is qualified, who bought, who dropped out? That's exactly the information missing from the ad account until you send it back. How well Meta can match your uploaded or sent data to people depends heavily on how many identifiers you include. For background, see the guide on how to improve Meta Event Match Quality.

LeadMetrics sends events like lead, purchase or deal won with hashed email, phone number and name plus click IDs through the Conversion API to Meta Ads, Google Ads, TikTok and LinkedIn. That way the platform learns which leads actually became customers.

Common mistakes

  • Not excluding buyers: Existing customers keep seeing acquisition ads and eat up budget.
  • Outdated lists: A customer list you uploaded once doesn't update itself.
  • Audiences that are too small: Very small custom audiences barely deliver, if at all.

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Frequently asked questions

That depends on your legal basis and consent. Meta hashes the data before matching, but that doesn't replace a legal review. Check with your data protection officer. This is not legal advice.

Guides on this topic

Tracking9 min read

How to Improve Meta Event Match Quality: What Data to Send

How to improve Event Match Quality in Meta: which customer data counts, how to normalize and hash it, and how fbc, fbp and event_id help your score.

Read guide

Related terms

All terms

Lookalike Audience

A lookalike audience is a target audience an ad platform builds from people who closely resemble a source list you provide, such as your best customers.

Retargeting

Retargeting shows ads to people who have already interacted with your brand, for example by visiting your website without filling out a form yet.

Hashing

Hashing turns data like email addresses into a fixed string using a one-way function (e.g. SHA-256), so the original can't be calculated back from it.

Tracking Pixel

A tracking pixel is a snippet of code from an ad platform that captures page views and conversions in the browser and reports them to Meta, Google and others.

Ad Set

An ad set is the middle level of an ad campaign: this is where you define the audience, placements, optimization goal and often the budget for several ads.

A/B Test

An A/B test compares two versions of an ad, audience or landing page that differ in exactly one element, to find out which one performs better.