utm_medium for email, influencers and affiliates: which channel it lands in

Published October 10, 2026 by the UTM Builder team at Limner.

Use email for email and newsletters, affiliate for affiliates, sms for SMS and push for notifications. These are values the GA4 default channel group rules recognize. Influencers don’t have a channel of their own: what decides is the source and whether the post is paid.

The table

What’s behind each row, according to the default channel group page:

• Email: source or medium equal to email, e-mail, e_mail or e mail.
• Affiliates: medium equal to affiliate. Use the singular, in English.
• SMS: source or medium exactly sms.
• Push: medium ending in push (push and web-push both work), medium containing mobile or notification, or source exactly firebase.
• Organic Social: source on Google’s list of social sites, or medium social, social-network, social-media, sm, social network or social media.
• Paid Social: source on the social sites list and medium matching ^(.*cp.*|ppc|retargeting|paid.*)$.

The rules are case-insensitive, but the reports aren’t. Write everything in lowercase. And if you read the help in Portuguese, be careful: that version shows afiliados and notificação where the English version shows affiliate and notification. The guide on capitals, accents and spaces has the comparison.

Why newsletter and influencer end up in Unassigned

There’s no channel rule for the medium newsletter or for influencer. With either one, GA4 only finds a channel if the source matches some rule. If it doesn’t, the visit goes to Unassigned.

• utm_source=rd-station&utm_medium=newsletter: no rule matches. Unassigned.
• utm_source=newsletter&utm_medium=email: the medium matches Email. The newsletter is still identifiable by its source.
• utm_source=maria-silva&utm_medium=influencer: neither the source nor the medium matches. Unassigned.
• utm_source=instagram&utm_medium=influencer: instagram is on Google’s list of social sources and influencer isn’t a paid medium. Organic Social.

The last format is the most useful one for influencers. In the default group, the visit lands in the social channel. In a custom channel group, you can create an Influencers channel with the condition medium exactly matches influencer and separate that traffic from your own organic. The creator’s name goes in utm_content or utm_campaign. If the creator is paid on commission and you treat them as an affiliate, use affiliate with their name as the source.

Coupons and links measure different things. The UTM records who clicked; the coupon only shows up on the order. To match the two, give each creator a coupon and a link with the same name.

Automatic UTMs from your email tool

Some tools add UTMs on their own. In Mailchimp, the Google Analytics link tracking option is checked on each email. In automation flows, you can edit each email’s parameters under Modify UTM Parameters, and the help asks you not to leave any field blank. The single welcome email doesn’t accept this tracking. The title sent to Google Analytics combines the email title with the date.

Mailchimp’s help doesn’t list the default source and medium values. Whatever the tool, run two checks on a test send:

• Open the link in the email and read the final URL. If you also added UTMs by hand, make sure you didn’t end up with two utm_source parameters.
• Confirm that the recorded medium is email. If the tool uses a different value, edit it there, or turn the feature off and use your own UTM.