ChatGPT Ads Can Target You by Email or Phone Number

ChatGPT ads can be matched to specific users through their email address, phone number, or Android advertising ID. Gizmodo reported the finding on October 16, based on test ad campaigns that 404 Media had run directly on the platform.

Advertisers can upload a list of target emails, phone numbers, or Android device ad IDs. The list can be submitted either in plain text or as hashed values. These lists often come from a company's own customer database.

OpenAI checks uploaded lists against ChatGPT accounts and only qualifies matched users to see the related ad. It does not tell advertisers whether a given entry matched, so the feature cannot be used to confirm whether a specific person has a ChatGPT account.

Running this kind of targeting requires a list of at least 25,000 entries. OpenAI said uploaded files are deleted within 24 hours of processing. The article noted it isn't clear whether the original data is stored in hashed form before that.

Turning on ChatGPT's ad personalization opt-out excludes ads based on past conversations, activity, and inferred preferences. Whether it also blocks this identifier-based targeting isn't clear. OpenAI said ads based on the current conversation can still appear regardless.

Being on a list doesn't guarantee a matched user will actually see the targeted ad, OpenAI added. Gizmodo asked OpenAI for further comment but hadn't received a response by publication time.

404 Media also raised concerns about the possibility that the original data is stored without hashing. The article noted that encryption practices during upload haven't been clearly disclosed, so a data exposure risk can't be ruled out entirely.

The report shows ChatGPT's ad ecosystem moving closer to the identifier-based targeting long used in traditional digital advertising. With ChatGPT's user base past one billion, how far this targeting reach extends is likely to keep drawing scrutiny.

The approach resembles the "custom audience" matching tools Meta and Google ads have offered for years. But because ChatGPT also handles the content of users' conversations, similar targeting mechanics may carry a different weight in practice.

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If your company holds a list of customer emails or phone numbers, it's worth factoring this kind of matched targeting into how you think about ChatGPT ad campaigns going forward.

Source: Gizmodo, October 16, 2026. Checked October 21, 2026. Read the original