Google Gemini has started adding UTM parameters to outbound links, so Gemini traffic can now be counted in GA4

A site that gets a click from a Gemini answer has for most of this year had no reliable way to count it. Yesterday the parameters started arriving on outbound links, so Gemini traffic will land in a named source in GA4 instead of in the unknown Direct bucket, according to Search Engine Journal reporting on 1 October 2026.

The reporter, Roger Montti, cites a Reddit post that first spotted the change: "Gemini Start using UTM! finally, its very new 24 hours or so. Like chatgpt UTM." SEJ confirms it is happening and sets out what changes.

Why Gemini traffic was ending up in Direct

A visit from an AI chatbot has to carry a signal for GA4 to attribute it. Without a referrer header or a UTM query string, GA4 falls back to the Direct channel, so sites that already get a lot of generative-engine traffic have no way to tell how much came from Gemini and how much is genuinely direct.

Gemini did send a browser referrer, but only on desktop web. One commenter quoted in the SEJ piece says pass-through from the Gemini mobile app ran around 9 percent, and that Android assistant invocations stripped the referrer entirely. So a large share of Gemini-sourced visits had been landing in Direct instead of the ai_assistant medium GA4 uses for recognised chatbot sources.

What changed and how it compares to ChatGPT

The outbound links in Gemini answers now carry UTM parameters, so the receiving site can recognise them regardless of the referrer. GA4 will attribute them to a named source, and the sessions can be filtered and segmented in reports.

Montti compares the behaviour with ChatGPT, which has added UTM parameters for a while on the links inside answers grounded in web sources. SEJ notes that Google's implementation is undocumented at this point, so the trigger is still unknown: presumably when the answer references a website directly, but that is Montti's inference and Google has made no public statement.

The consequence for a team doing GEO work

The useful thing is that a site can now justify time spent on generative-engine visibility with a measured number instead of a guess. SEJ argues the attribution lets a team segment Gemini visitors, compare them against ChatGPT and traditional search, and allocate resources with real signal. For teams in the middle of a GEO pilot, the practical first move is to confirm the UTM is coming through on live Gemini traffic (search for the brand term and click the citation), check that GA4 is receiving a non-Direct source for that visit, and build a Gemini-attributed segment in GA4 before the historical data gets lost in the Direct noise.

The scale of what starts getting counted is not stated. The Gemini app passed a billion monthly users in August by Sundar Pichai's own figure, so a site that was never attributing those visits is likely to see the Direct share drop and a Gemini-attributed share appear. How large depends on the share of Gemini answers that cite the web and on which of those citations get the parameter, both of which Google has not documented.

Source

• Primary source: Search Engine Journal: Google Gemini Adds UTM Parameters For Referral Attribution, 1 October 2026