UTM parameters

UTM parameters are five standardized query-string tags appended to URLs to record where a visitor came from: utm_source (the site or platform, like google or newsletter), utm_medium (the channel, like cpc or email), utm_campaign (the specific campaign), utm_term (the paid keyword), and utm_content (the specific ad or link variant). The name survives from Urchin Tracking Module, the analytics product Google acquired and turned into Google Analytics.

They work because they are dumb. A UTM tag is just text in a URL - no cookies, no scripts, no platform lock-in - which is why every analytics tool, email platform, and ad network understands them. You tag outbound links once, and any page that reads its own URL can know which campaign produced the visit.

Their weakness is persistence. UTMs live on the landing page's URL only; the moment a visitor clicks to a second page, they are gone. Any system that wants to attach campaign data to a later action - like a form submission three pages deep - has to capture the parameters on arrival and carry them forward itself.

The SheetLink Forms embed handles that carrying automatically. When sl.js loads, it captures utm_source, utm_medium, utm_campaign, utm_term, and utm_content from the URL, persists them in localStorage across pages, and attaches them to any submission it sends - so the row that lands in your sheet carries the campaign that produced it, even when the form is nowhere near the landing page. The same mechanism captures ad click IDs like gclid.

The capture flow is walked through in the guide on capturing gclid in forms, and you can see attribution columns fill in on the live demo.