Custom Audience
A custom audience is an ad-targeting segment built from your own first-party data, such as customer email lists, website visitors, or app users, uploaded or synced to an advertising platform.
In depth
A custom audience lets you advertise to people you already have a relationship with, rather than strangers selected only by interest or demographic targeting. You create one by providing identifiers, hashed emails, phone numbers, or pixel/SDK events, which the platform matches against its user base to assemble a reachable segment. Because the input is your own data, custom audiences power high-relevance use cases like retargeting cart abandoners, re-engaging trial users, or suppressing existing customers from acquisition campaigns.
The biggest pitfall today is data hygiene and consent: shrinking match rates, privacy regulations, and the decline of third-party cookies mean a custom audience is only as good as the freshness and lawful basis of the data behind it. Lists also decay quickly as emails go stale and people change jobs, so audiences must be refreshed rather than set once. In a quiz-funnel and lead-qualification workflow, the funnel collects explicit, consented contact details alongside a fit score, giving you clean, segment-ready first-party data, so you can build a custom audience of, say, only high-scoring leads and exclude unqualified ones from costly ad spend.
Example in practice
Frequently asked questions
What is the difference between a custom audience and a lookalike audience?
A custom audience is built from your own first-party data of known contacts, while a lookalike audience uses that data as a seed to find similar new prospects. You typically create the custom audience first, then expand reach with a lookalike.
Why do match rates for custom audiences vary so much?
Match rates depend on data freshness, the identifiers you provide, and how many of your contacts use the platform with the same details. Stale lists and missing consent both lower the share of records the platform can successfully match.
Can I use a custom audience to exclude people?
Yes, exclusion is one of the most valuable uses. You can suppress existing customers or unqualified leads so your acquisition budget targets only new, high-fit prospects.