OpenAI Pixel.

The pixel works like other client-side tracking tags: a script sits on the website, fires on defined events, such as a submitted form or a completed purchase, and reports them to OpenAI. It is therefore subject to the same limitations as any browser-side tag: missing consent, script blockers, a change of device between click and conversion or a conversion by phone mean that an event is never created in the first place. If you judge a campaign solely by the pixel figures, you are measuring measurability, not demand.

The server-side Conversions API closes some of these gaps because it sends events from your own system rather than from the browser. The most important practical difference concerns attribution: the oppref parameter, which OpenAI appends to the landing page URL on a click, is read automatically by the pixel. With the Conversions API you have to capture it yourself, carry it along in your own data and return it when reporting the event. If this is forgotten, the events arrive but cannot be assigned to any click; this is the most common set-up error with server-side measurement.

An example of combining the two: an online shop uses the pixel for the completed purchase in the browser and also reports the same purchase server-side from the shop system. Both reports carry the same pixel ID, the same event_name and the same event ID; the event that arrives first is counted. If the browser-side route fails, the server-side one steps in without the purchase being counted twice. The prerequisite is that the event ID really is issued identically on both routes; otherwise one purchase produces two conversions, and the entire evaluation is worthless.

Two windows belong to attribution. The view-through window covers at most one day after a valid impression (adjustable to zero or one day in reporting), and the click-through window is configurable; where the two overlap, click attribution takes precedence. View-through conversions appear as a separate metric at campaign level and are not included in the conversion total; if you add them in, you count twice. That report figures catch up later is normal with every advertising system; there is no documented figure for how long this delay lasts with ChatGPT Ads, so we do not give one. As with every channel, attribution rules are an accounting convention, not proof of cause; see attribution model. According to OpenAI, changing the reporting window only affects reports, not bids, optimisation or billing. This description reflects the situation on 11 October 2026, checked against the OpenAI Help Center ('Measure Results').