Questions people ask
What is the difference between utm_source and utm_medium?
Source is where the click came from: google, facebook, newsletter, a partner site. Medium is the type of traffic: cpc, paid_social, email, social, referral. GA4 groups channels by medium, so a wrong medium value puts the traffic in the wrong report.
Should UTM values be lowercase?
Yes. Analytics tools treat Facebook and facebook as two different sources. Pick lowercase, pick one separator (this tool uses underscores) and use the same names every time. Consistency matters more than the exact words.
Do UTM parameters affect SEO?
Not when they are used on links from other places to your site. Do not put UTM tags on internal links on your own site, because that overwrites the original session source and splits your data.
Which parameters are required?
Source, medium and campaign are the three that GA4 expects. Term and content are optional and useful for paid search keywords and for telling two creatives in the same campaign apart.