OpenAI Lets Advertisers Match Customer Emails to ChatGPT Ad Audiences

OpenAI is allowing advertisers to use customer email addresses and phone numbers to build targeted audiences for advertisements on ChatGPT, adding another layer to the platform’s advertising system. The capability came into focus after an investigation by 404 Media on October 15, 2026, found that advertisers could upload customer lists and combine audience targeting with signals related to the topics people discuss with ChatGPT. The development raises questions about how information collected outside an AI chatbot can influence the advertising users encounter inside it.

OpenAI says advertisers cannot see users’ private conversations, chat histories, memories or the identities of individual people matched to their customer lists. Instead, the company says its system uses audience matching internally to determine eligibility for advertisements, while advertisers receive aggregated performance information. ChatGPT’s current conversation can also influence ad selection, and selected signals from previous chats may be used when ad personalisation is enabled. The distinction is important: the system does not give advertisers direct access to private chats, but it allows external customer data and activity within ChatGPT to play roles in deciding which advertisements may be shown.

Key Takeaways

• Customer-list targeting: Advertisers can upload email addresses and phone numbers to create audiences for ChatGPT ads.
• Conversation-based relevance: The topics and intent of a user’s current conversation can influence ad selection.
• Personalisation controls: When enabled, selected signals from past chats and memory can also help determine relevant ads.
• Minimum audience threshold: OpenAI says inclusion targeting requires at least 25,000 matched users.
• Privacy safeguards: OpenAI says advertisers cannot see individual matches, private chats or chat histories.
• File processing: OpenAI told 404 Media that uploaded audience files are generally deleted after processing, usually within 24 hours.
• User controls: Turning off ad personalisation limits the use of broader ChatGPT activity, but does not necessarily remove ads or prevent the current chat from influencing them.

How Email-Based Ad Targeting Works

Customer-list targeting is a common feature of digital advertising. Businesses often maintain lists of customers, subscribers or prospective buyers and use those lists to reach people on advertising platforms.

For example, an online retailer might have email addresses for customers who previously purchased electronics. Rather than showing an advertisement to everyone, the retailer could upload the list to an advertising service and ask the platform to make the campaign eligible for a matching audience.

OpenAI’s advertising system adds this type of audience matching to ChatGPT. Advertisers can submit raw or hashed email addresses and phone numbers, along with Android advertising identifiers. A hashed identifier is a digitally transformed version of information such as a