How to Write UTM Source for an Email Newsletter Campaign

How to write UTM source for an email newsletter campaign: use utm_source=newsletter and utm_medium=email, with utm_campaign naming the specific issue or offer, because GA4 groups traffic by those exact values and a consistent source keeps every issue comparable. Build each link free with our UTM builder instead of hand-typing parameters into every email link.

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The Short Answer, With the Reasoning

The source answers the question where did this visitor come from, and for a newsletter the honest answer is the newsletter itself, not the email platform and not your company name. That is why utm_source=newsletter is the standard choice: it stays identical across every issue, every list segment, and every sender tool you might switch to later. Using the platform name, such as mailchimp or convertkit, answers a different question, namely which tool sent the mail, and it breaks your history the day you change tools. Using your brand name as the source wastes the field, because the brand is already implied by the site the visitor lands on. Newsletter is stable, readable in a report, and instantly understood by anyone who opens GA4 after you.

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utm_source=newsletter vs the Sender Name

The most common alternative is the sender name, such as weekly-digest or the-james-letter, and it is worth understanding before rejecting it. A sender-name source makes sense when one account sends several genuinely different publications, for example a daily news brief and a monthly research letter, because then the source distinguishes the publications and the campaign can name the issue. For a single newsletter, though, the sender name adds a distinction nobody needs and creates a second source the moment someone writes it slightly differently. Our guide explaining utm_source vs medium vs campaign draws the same line: source is the property, campaign is the individual send. If you run one newsletter, newsletter is the source and the issue name belongs in the campaign value, where it can change every week without splitting the source.

utm_medium=email, Not Newsletter

The medium answers how the visitor arrived, and for email that answer is email, not newsletter, because GA4's channel rules recognise email as a medium and group it into the Email channel. Writing utm_medium=newsletter is the single most common newsletter-tagging mistake, and it pushes the traffic into an unassigned or other bucket instead of the Email channel, which makes the newsletter look like it sent nobody. The swap feels natural, since people say newsletter email as one phrase, but source and medium are two different slots and each has its own correct value: source newsletter, medium email. Keep the pair fixed as newsletter / email on every link in every issue, and let campaign and content carry all the variation, so the channel report stays clean while the per-issue detail stays visible.

utm_campaign: Name the Issue, Not the Month

Campaign names should identify one send so you can compare issues against each other, which means a value like october-newsletter is too vague and a value like 2026-10-31-product-launch is exactly right. Include the date or issue number plus a short topic slug, keep it lowercase and hyphenated, and never reuse a campaign name for a different issue, because GA4 will merge the two sends into one row and you will never separate them again. For a promotional series, use one campaign for the whole series only if you genuinely want series-level reporting, and otherwise give each email its own campaign so the winner is visible. A good campaign value reads like a file name: dated, specific, and boring, because boring names are the ones a future analyst can trust.

utm_content: One Value Per Link Position

A newsletter usually contains several links, and utm_content is how you learn which one earned the click, so give the logo, the hero button, and the footer link different content values, such as header-logo, hero-cta, and footer-ps. Without content values, all clicks from one issue collapse into a single row and you cannot tell whether the main offer or the postscript did the work, which is exactly the insight a newsletter test needs. This is the same discipline our UTM medium examples for social media apply to social links, where the button or placement is the variable. Keep content values short and positional rather than clever, because the report will be read by someone deciding which slot to sell or cut, and hero-cta is actionable in a way that link-3 is not.

Case Sensitivity and the Trailing-Slash Trap

UTM values are case-sensitive, so Newsletter, newsletter, and NEWSLETTER become three different sources in GA4, and a campaign split across cases is the hardest reporting bug to notice because every row looks plausible on its own. Pick lowercase for everything, enforce it in your email template, and check the first send of each month for capital letters before the list grows. The trailing-slash trap is subtler: yoursite.com/page and yoursite.com/page/ can be treated as different landing pages, so pick one form and use it in every link. Our UTM builder keeps the casing and structure you type, so the discipline has to live in your template, not in the tool. Add a pre-send checklist line, check UTM casing, and have a second person verify it on the test send, because a typo caught in testing costs nothing and a typo in a live send corrupts that issue's data permanently.

Checking the Send in GA4

After the send, open GA4's traffic acquisition report and filter to session source newsletter and session medium email, where the issue's campaign should appear with its sessions and conversions. For a same-day check, use the Realtime report during the first hour after sending and watch for the spike, which confirms the links survived your email platform's click tracking. Most email platforms wrap links in their own redirect for click measurement, and a correct wrapper preserves UTM parameters, but a misconfigured one can strip them, so the test click from a real inbox is mandatory, not optional. If clicks appear without parameters, the platform's link handling is the suspect, and its support docs on click tracking are the fix. While you are there, check the newsletter's length before the next issue with our free word counter, and turn total reading time into hours for the report with our free minutes to hours converter when an issue runs long.

Segmenting by List Without Splitting the Source

When one newsletter goes to several list segments, such as free readers and paying members, the temptation is to give each segment its own source, but that splits the newsletter into two sources and breaks the issue-to-issue comparison this article is built around. Keep utm_source=newsletter for every segment and carry the segment in utm_content or in a campaign suffix, for example utm_campaign=2026-10-31-product-launch-members, so the segment stays visible without creating a new source row. The same rule applies to A/B subject-line tests: the subject variant belongs in the campaign or content value, never in the source, because the test compares two sends of the same newsletter, not two different publications. If a segment later becomes a genuinely separate publication with its own name, cadence, and audience, that is the moment to give it its own source, and to note the change date in your tracking log so nobody compares pre-split and post-split rows as if they were the same series.

A Template for Every Issue

Copy this template and change only the campaign and content values: yoursite.com/offer?utm_source=newsletter&utm_medium=email&utm_campaign=2026-10-31-product-launch&utm_content=hero-cta. The logo link keeps the same campaign but uses utm_content=header-logo, and the footer link uses utm_content=footer-ps, so one issue produces three readable rows instead of one mystery row. Save the template in your email platform as a snippet or a default link format so nobody hand-types parameters under deadline pressure, because hand-typed parameters are where casing errors and missing values are born. Consistent source, correct medium, dated campaign, positional content: four decisions made once, reused every issue, and your newsletter reporting stays trustworthy for years.