The OpenAI Pixel, called the ChatGPT Ads Measurement Pixel in OpenAI's developer documentation, is a browser SDK (a small JavaScript library) that measures website events which can be attributed to ads in ChatGPT. It belongs to OpenAI's advertising system for ChatGPT, where advertisers manage campaigns in Ads Manager.
The advertiser adds a script to the head of each page; it loads oaiq.min.js from bzrcdn.openai.com and is initialized with a Pixel ID created in the conversions tab of Ads Manager. When a visitor completes an action, such as a purchase, a lead or a registration, the page calls oaiq("measure", ...). OpenAI appends a click reference called oppref to the landing page URL; the pixel stores it in a first-party cookie for 30 days and links later conversions to the ad click. The pixel can also hash customer details found in forms with SHA-256 in the browser (automatic advanced matching). A consent setting blocks measurement until the visitor agrees. A server-side Conversions API can send the same events, and a shared event ID removes duplicates.
The pixel comes with a ChatGPT Ads account; the documentation names no separate fee for it.