Table of Contents
utm_source meaning: utm_source is the UTM parameter that tells analytics tools where a click came from: the website, platform, publisher or newsletter that sent the visitor. In ?utm_source=google&utm_medium=cpc, the source is google. Choose values your team can recognize and use them consistently.
What Is utm_source?
Put simply, utm_source answers "who sent this visit?" while utm_medium answers "through which channel?". Typical values are google, facebook, linkedin, newsletter or a partner's domain.
In Google Analytics 4, utm_source populates the Session source and First user source dimensions. Including it in manually tagged campaigns is a useful convention, but when it is missing GA4 may still have referrer, advertising-platform, or other traffic-source information. Review those values before concluding that the session will be reported as (direct), (not set), or another classification.
Approved utm_source Values by Platform
Choose consistent platform names to make reporting rows easier to compare. The examples below use lowercase as a naming convention:
| Marketing Channel | Approved utm_source Value | Forbidden Variations (Will Split Reports) |
|---|---|---|
| Google Ads / Search | google |
Google, googleads, adwords |
| Meta (Facebook & Instagram) | facebook, instagram, or meta |
FB, Facebook_Ads, ig |
| LinkedIn Ads / Organic | linkedin |
LinkedIn, lnkd, li |
| X (Twitter) | x or twitter |
Twitter, tweet, x.com |
| Email Marketing | newsletter, klaviyo, hubspot |
email (this is a medium, not a source!) |
| Affiliates / Partners | [partner_name] (e.g. wirecutter) |
affiliate (this is a medium!) |
What Does utm_source=chatgpt.com Mean?
If you see utm_source=chatgpt.com on your landing pages or as a source in GA4, the visitor clicked a link to your site inside a ChatGPT answer. ChatGPT appends that tag to many of the links it shows, so the visit is reported as coming from chatgpt.com instead of falling into Direct. You did not add it, and you do not need to remove it. To report AI assistants as their own group, see how to track AI assistant traffic in GA4.
The Difference Between Source and Medium
Source = The WHO (The specific publisher: google, facebook, substack).
Medium = The HOW (The transmission channel type: cpc, paid_social, email).
Common utm_source Mistakes That Break GA4
A very common tracking error is setting utm_source=email&utm_medium=email or utm_source=email&utm_medium=newsletter. Email is the vehicle (medium), not the source. Your source should be the specific publication or platform sending the message, such as newsletter_weekly, product_updates, or klaviyo.
For the broader setup, read Complete UTM Parameters Guide for GA4: Manual Campaign Dimensions & Best Practices. Browse the UTM Parameters guides to choose another troubleshooting task.
References
- Traffic-source dimensions in GA4 (Google Analytics Help)
