ChatGPT Is Now Running Ads Inside Your Conversations. Here's Exactly How It Works.

If you've asked ChatGPT for a product recommendation lately, there's a real chance the answer you got was paid for by someone.

A researcher named Luca Buchodi published a detailed technical breakdown on April 28th showing - with captured live traffic - exactly how OpenAI's advertising system works inside ChatGPT. This isn't speculation. He observed the actual data flowing through the system using a consented research panel.

Here's what's happening, in plain language.

What the ads look like inside ChatGPT

When you send a message to ChatGPT, the backend opens a streaming response (called an SSE stream). Most of what comes back is the AI's output. But some of it is now a structured ad object. Buchodi captured one from Grubhub that looked like this in the raw data:

A user was planning a trip to Beijing. ChatGPT recommended Chinese food delivery. The ad that ran: Grubhub - "Satisfy Your Cravings with Grubhub Delivery."

Same conversation topic, same brand category. The targeting is contextual - meaning OpenAI reads what you're talking about and serves an ad that fits the moment.

Here's a sample of what he observed across six different conversations:

Trip planning for Beijing - Grubhub Chinese food delivery
Beijing tour bookings - GetYourGuide, Great Wall tour
NBA playoffs discussion - Gametime tickets
Spring fashion trends - Aritzia
Productivity help / slide decks - Canva

Same account. Different topic. Different advertiser every time.

The tracking goes further than the chat

This is the part that matters most for business owners.

When you click an ad inside ChatGPT, OpenAI opens the merchant's page inside their own in-app browser - so they can see your post-click navigation on top of any pixel data. The merchant's site then loads a tracking SDK called OAIQ (OpenAI's attribution tool) that drops a cookie called __oppref with a 30-day lifespan.

Translation: OpenAI tracks what you do after you click, on the merchant's website, for a month.

The whole system - ad injection, click tracking, cross-site measurement - is already live. Buchodi found it active with real advertisers including Grubhub, GetYourGuide, Canva, and Home Depot.

What Sam Altman said two years ago

In 2023, Altman described ads as "a last resort" for OpenAI's business model: "I would do it if it meant that was the only way to get everybody in the world access to great services."

The system is apparently live now. OpenAI has not made a public announcement about when the ad program officially launched or how widely it's running.

What this means for you as a small business owner

If you use ChatGPT to research vendors, tools, or products: The recommendations you receive may now be influenced by who paid for placement. It doesn't mean the recommendation is wrong - contextual ads can still be relevant - but you should know the information may not be neutral.

If you're a small business thinking about advertising: This is a brand new ad channel. The targeting appears to be contextual (based on conversation topic), not behavioral (based on your history). That's actually a different model than Google or Meta, which use years of behavioral data. It's worth watching.

If you're concerned about privacy: Two domains to be aware of: bzrcdn.openai.com and bzr.openai.com. Two cookie names: __oppref and __oaiq_domain_probe. These appear in your browser after clicking a ChatGPT ad recommendation.

The bottom line

The AI tool you've been using for research and vendor decisions is now also an ad platform. That doesn't make it useless - but it does mean you should cross-reference recommendations that involve a purchase, especially for services, software, and vendors.

The free version of ChatGPT is where this appears to be running. Paid subscribers may see fewer or no ads - though OpenAI hasn't officially clarified the policy.

When a tool gives you advice and also accepts money from the companies it's advising about, the right response isn't to stop using the tool. It's to know what you're looking at.

Source: Luca Buchodi, "How ChatGPT serves ads - Here's the full attribution loop," buchodi.com, April 28, 2026. Community discussion: Hacker News thread 47942437.

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