What Is utm_source? A Practical Guide

utm_source identifies the place where a tracked visit started. It is usually the name of a platform, publication, partner, or distribution channel that sent someone to your website.

For example, a link shared in a Facebook post might use utm_source=facebook, while a link in your weekly newsletter might use utm_source=newsletter. The parameter gives your analytics reports a consistent answer to the question: where did this visit come from?

What does utm_source mean?

Source is the specific origin of the traffic. It is not the campaign name and it is not usually the type of channel. Those are represented by other parameters.

https://example.com/pricing?utm_source=linkedin&utm_medium=organic_social&utm_campaign=summer_launch

Here, linkedin is the source. organic_social describes the medium, and summer_launch identifies the campaign.

What should the value be?

Use a short, recognizable, lowercase value that identifies the actual origin of the link. Good values are easy to read in a report and can be used consistently by everyone on the team.

• google for a Google placement when your tracking plan calls for it.
• facebook for Facebook links.
• instagram for Instagram links.
• linkedin for LinkedIn links.
• newsletter for a recurring email newsletter.
• partner_name for a named partner.

Source is not the same as medium

A common mistake is to put the same value in both fields. Source answers where; medium answers what kind of traffic or channel.

utm_source=facebook
utm_medium=paid_social

utm_source=newsletter
utm_medium=email

There can be several sources within one medium. Facebook, Instagram, and LinkedIn can all belong to a social grouping, depending on your reporting convention.

Why lowercase matters

Many analytics systems treat values with different capitalization as different values. That means Facebook, facebook, and FACEBOOK may appear as separate rows instead of one clean source.

Choose one spelling and use it everywhere. Lowercase is the simplest convention: use facebook, newsletter, and partner_acme.

Common mistakes

Using a different spelling for every link

Decide whether your team uses facebook or fb, then document the decision. Both can work; inconsistent use is what causes reporting problems.

Putting the campaign name in the source

utm_source=summer_sale does not tell you where the traffic came from. Keep the campaign in utm_campaign and the platform or distribution origin in utm_source.

Creating a new source for every creative

Different ads or buttons usually belong in utm_content. The source should stay stable when the origin stays the same.

A simple source naming convention

1. Use lowercase values only.
2. Use one spelling for each platform or partner.
3. Use underscores between words when needed.
4. Keep a short approved list and add new values deliberately.
5. Do not use source values for campaign names or creative variants.

A short approved list prevents reports from filling up with near-duplicates. It also makes links easier to build for colleagues who do not work in analytics every day.

Build a link with a consistent source

Once your source, medium, and campaign values are decided, use the BestUTM builder to create and copy the final URL. Before publishing it, check the spelling and make sure the link points to the intended landing page.