Custom audiences give advertisers explicit customer-list controls. They can restrict eligibility, suppress existing customers or modify bids — but they are a separate layer from context hints and conversational relevance.
Last verified September 23, 2026 · OpenAI source documentation + current Magnify product capabilities.
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OpenAI supports audience files containing email addresses, phone numbers, SHA-256 hashed email or phone identifiers, and Google Advertising IDs. Ads Manager processes those files into matched audiences rather than exposing individual matched users.
Campaign-level inclusion limits eligibility to selected audiences, while exclusion prevents selected audiences from receiving the campaign. OpenAI currently requires at least 25,000 matched users for inclusion; smaller matched audiences can still be used for exclusions.
Eligible custom audiences can receive an ad-group bid multiplier. OpenAI currently documents multipliers from 0.1x to 10x, with the highest matching multiplier applied when someone belongs to multiple selected audiences.
OpenAI's current campaign guidance says to avoid custom audiences for campaigns targeting the EEA or Switzerland while ads personalization is unavailable there. Always re-check current regional rules before launch.
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FAQ
OpenAI currently documents 25,000 matched users as the minimum for inclusion targeting and audience bid adjustments. Smaller matched audiences can be used for exclusions.
Yes. OpenAI documents campaign-level exclusion as a use case for existing customers, recent purchasers or other groups that should not receive a campaign.
OpenAI's advertising product is evolving quickly. These primary sources are the reference point for platform facts on this page.
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