UTM parameters
Measurement and data
Measurement and data
UTM parameters are snippets you add to a link so your analytics shows which source, medium and campaign a visitor came from.
A link with ?utm_source=newsletter&utm_medium=email&utm_campaign=summer shows exactly where traffic came from in GA4, even when the referring source doesn't pass that itself.
Agree one convention (all lowercase, fixed source names) and write it down. Two spellings of the same channel split your reporting without anyone noticing.
Tip
Use UTMs only on links coming from outside your own site: that preserves the original source and avoids starting an unnecessary new session.