Oriva

oppref: the ChatGPT Ads click identifier

Published on by the Oriva team.

OpenAI automatically adds oppref to the end of your landing page address when someone clicks your ChatGPT ad (?oppref=…). It is an opaque value, to be left unmodified, that ties a sale to a precise click. The OpenAI pixel reads it and keeps it 30 days in a cookie; the Conversions API does not read it: your server has to keep it and send it back, as it is, with the sale.

The click on a ChatGPT ad adds oppref to the address: the OpenAI pixel reads it, the Conversions API has to receive it from your server.

Where does it live?

In the landing address, then in the __oppref cookie the pixel sets on your domain. The cookie lasts 30 days and starts again at 30 days each time the pixel picks up a non-empty oppref again; reading the cookie does not extend it. It is only set if measurement consent is granted, and switching consent to “no” deletes it, along with __obref. A browser may shorten these durations.

What do I have to do on the server?

The Conversions API does not capture it for you. Keep it when the visitor arrives and across redirects and navigation, then send back the original string, unmodified, in the event's oppref field (at the event level, not inside user). Never reuse another person's oppref or a default value. The obref cookie, for its part, goes in user.obref.

Is it required?

No, the field is optional. It is the most direct signal for finding the click, but OpenAI also relies on advanced matching (hashed customer data) and, where available, on modeled measurement: the conversion total can include modeled conversions.

What happens if it goes missing?

Ads Manager shows the warning “Ad click information is missing or cannot be connected”. A redirect (from www to the bare domain, from http to https) or a host's cache can strip address parameters before your site sees them: we have seen one strip gclid at a host.

To test, open an address of your site with ?oppref=test and check whether the parameter reaches the final page.

And the Image Tag?

The Image Tag, the path with no JavaScript, neither captures nor keeps oppref: if your page knows it, pass it in the image address.

How long does it stay valid?

OpenAI does not document it. What is documented: the pixel cookie's duration (30 days) and the attribution windows.

What Oriva does with it

Oriva's tracking code reads oppref in the address, with the pixel__oppref cookie as a fallback, counts it as a click for attribution and sends it back in the event's oppref field. It is only read with the visitor's advertising consent. obref goes in user.obref and never creates a touchpoint on its own.

The setup details are on the ChatGPT Ads page, and the whole context (pixel, API, consent) in the Track ChatGPT Ads conversions guide.

Keep reading

Sources

OpenAI pages read on October 13, 2026.