What is utm_source=chatgpt.com?

Who adds it

OpenAI's ChatGPT adds it to links in its answers when it sends people to a website. OpenAI's publisher FAQ said ChatGPT includes utm_source=chatgpt.com in referral URLs from ChatGPT search results.

What it means

Someone clicked a link to your site in a ChatGPT answer. The same visit usually carries a chatgpt.com referrer too; the tag survives in the URL even when the referrer is stripped. GA4 files referrals from a list of AI assistants under its AI Assistant channel.

What to do with it

Keep it: it's the clearest signal of ChatGPT traffic. If people copy the tagged URL and share it, later visits from that copy carry the tag too, so a canonical tag on the page helps search engines treat it as the clean URL.

How Vireo shows it

Vireo Pro's UTM campaigns card lists tagged visits by Source, Medium and Campaign, with visitors and pageviews. The tags are read from the first page of each visit, and the same tags feed revenue by source.

In the free plugin, Vireo drops the query string from page addresses, keeping only a few WordPress ones such as p and page_id, so a tagged URL counts as the same page as the untagged one. The visit is counted under the referrer it arrived with.

When a link carries utm_source with no utm_medium, as ChatGPT's do, Pro's revenue attribution takes the medium from the referrer's source group. With no referrer either, it's labelled campaign.

UTM campaigns are part of Vireo Pro. See UTM campaigns in the docs.

Sources

ChatGPT automatically includes the UTM parameter utm_source=chatgpt.com in referral URLs, enabling clear tracking and analysis of inbound traffic from ChatGPT search results.

Publishers and Developers - FAQ, OpenAI Help Center (Wayback Machine snapshot, 2026-10-04)

The medium is set to “ai-assistant” and the campaign is set to “(ai-assistant)” if the referrer matches a list of AI Assistants.

Default channel group - Analytics Help

How to Specify a Canonical with rel="canonical" and Other Methods - Google Search Central