UTM Parameters for Affiliate Links: Simple Shopify Guide

UTM parameters for affiliate links tell you exactly which partner, channel and campaign sent each visitor to your Shopify store. They are short tags added to the end of a URL, and they cost nothing to use. This guide explains what each UTM parameter does, how to name them for affiliates, and the mistakes that quietly break your reports.

What are UTM parameters?

UTM parameters are pieces of text you add after a question mark in a link. Analytics tools such as Google Analytics 4 (GA4) and Shopify's own reports read them when someone clicks the link and lands on your store.

Here is a simple affiliate link with UTM parameters:

https://yourstore.com/products/face-serum?utm_source=sara_beauty&utm_medium=affiliate&utm_campaign=summer_launch&ref=SARA10

The part before the ? is the normal product page. Everything after it is tracking data. The page looks the same to the shopper. Only your reports see the difference.

UTM stands for "Urchin Tracking Module." Urchin was an analytics company that Google bought, and the name stayed.

The five standard UTM parameters

There are five classic UTM parameters. Three of them do most of the work.

Parameter	What it answers	Affiliate example	Required?
`utm_source`	Who sent the visitor?	`sara_beauty`	Yes
`utm_medium`	What type of channel?	`affiliate`	Yes
`utm_campaign`	Which promotion or program?	`summer_launch`	Strongly recommended
`utm_content`	Which post, button or creative?	`ig_story_1`	Optional
`utm_term`	Which keyword? (mostly for paid search)	`vitamin_c_serum`	Rarely used for affiliates

GA4 also supports a few newer parameters, such as utm_id (a campaign ID) and utm_source_platform. Most small stores do not need them for an affiliate program.

utm_source: the affiliate

For affiliate links, utm_source should identify the affiliate. Use a short, stable name or ID, such as sara_beauty or aff_1042. This is the value you will filter by when you want to see one partner's traffic.

utm_medium: the channel type

Keep utm_medium the same for every affiliate link: affiliate. This lets you compare all affiliate traffic against email, paid social, organic search and other channels in one view. If some links say affiliate, others say Affiliate and others say partners, your channel totals split into three rows.

utm_campaign: the program or promotion

Use utm_campaign for the reason the link exists. Good examples:

affiliate_program for your always-on links
eid_sale or black_friday for a seasonal push
new_serum_launch for a product launch

utm_content: the creative

utm_content is useful when one affiliate posts in several places. An influencer might share the same product in a TikTok video, an Instagram story and a WhatsApp group. Give each link its own utm_content (for example tiktok_video, ig_story, whatsapp) and you can see which format works best.

Why UTM parameters matter for affiliate programs

A plain referral code tells you which affiliate gets credit. UTM parameters add context around that credit. Together they help you answer questions like these:

Which affiliates send traffic that actually buys, and which send clicks that bounce?
Is TikTok or Instagram traffic converting better for this product?
Did the seasonal campaign bring new visitors, or just shift existing buyers?
How does affiliate traffic compare with your paid ads on cost and conversion?

UTMs also give you a second opinion. If your affiliate app reports 40 orders from one partner but your analytics show almost no sessions from that partner, something is worth checking. That gap can point to broken links, coupon code leaks or suspicious orders. Our guide on affiliate fraud, self-referrals and fake orders covers what to look for.

UTM parameters vs referral codes vs coupon codes

These three tools are often confused. They do different jobs.

UTM parameters describe the traffic. Analytics tools read them to build reports. They do not, on their own, assign commission.
A referral code (often ref= in the link) identifies the affiliate to your affiliate app. The app uses it to credit orders.
A coupon code gives the shopper a discount and can also credit the affiliate, even without a click. This is helpful when people hear about a code in a video or a voice note and type it at checkout.

Most strong affiliate programs use all three. If you are deciding between codes and links, read affiliate coupon codes vs affiliate links.

How to build UTM links for affiliates

You can build UTM links by hand, with a free URL builder, or let your affiliate app generate them. The steps are the same.

Step 1: Write a naming guide

Decide your rules once and write them down. A one-page guide is enough. Typical starting points:

All lowercase
Use underscores instead of spaces
utm_medium is always affiliate
utm_source is the affiliate's handle or ID
utm_campaign comes from a short, fixed list

Step 2: Choose the landing page

Send people to the most relevant page. A product page usually converts better than the home page when the affiliate is talking about one product. For a collection or a sale, link to that collection.

Step 3: Add the parameters

Start with the page URL, add ?, then join each parameter with &:

https://yourstore.com/collections/summer?utm_source=aff_1042&utm_medium=affiliate&utm_campaign=summer_sale&utm_content=tiktok_video

If the URL already has a ? in it (for example a variant ID), add your UTMs with & instead of a second ?.

Step 4: Test every link

Before you send links to affiliates:

Open the link in a private browser window.
Check that the page loads and the UTMs stay in the address bar.
Look for the visit in your analytics real-time view.
If you can, place a test order and confirm the affiliate is credited in your affiliate app.

Step 5: Shorten for social and chat

Long links look messy in captions, bios and chat messages. You can use a link shortener or your own branded short domain. Always test that the short link keeps the UTM parameters after the redirect.

Common UTM mistakes (and how to avoid them)

Small errors cause most UTM problems. Watch for these.

Inconsistent capital letters

GA4 treats UTM values as case sensitive. Affiliate, affiliate and AFFILIATE show up as three separate rows. Pick lowercase and stick with it.

Spaces and special characters

Spaces turn into %20 or + and make reports hard to read. Use underscores or hyphens. Avoid characters like #, & or ? inside values, because they have special meaning in URLs.

Typos in parameter names

utm-source (with a hyphen) or utm_sorce will be ignored by analytics. Use a builder or a template so the parameter names are always correct.

Using UTMs on internal links

Do not add UTM parameters to links inside your own store, such as banners or menu links. When a visitor clicks one, analytics may start a new session and overwrite the original affiliate source.

Changing values in the middle of a campaign

If you rename summer_sale to summer_sale_2 halfway through, your data splits. Keep values stable and create a new campaign name only for a new campaign.

Relying on UTMs alone for commission

UTMs live in the URL. When a shopper leaves and comes back later by typing your address, the UTMs are gone. Some apps and browsers also strip query parameters. That is why commission should not depend on UTMs alone. Pair them with a referral code, a cookie and, where it fits, a coupon code.

UTM tracking for cash on delivery stores

COD stores face an extra challenge. Many COD checkouts use a form app instead of the standard Shopify checkout. The shopper fills in a name, phone number and address on the product page, and the order is created right away.

That flow is fast for shoppers, but it can make attribution harder:

The order may be created without passing through the normal checkout steps that some tracking tools rely on.
A COD order is not real revenue until it is delivered and paid for. A click that leads to a refused parcel should not count the same as a delivered order.

For COD stores, it helps to save the affiliate referral on the cart or order itself, not only in the URL. It also helps to wait until delivery before approving commission. Our guide on COD affiliate marketing explains how to pay commission only on delivered orders.

When you read your UTM reports, remember that sessions and "orders placed" can look better than real results in COD markets. Compare affiliate traffic against delivered orders, not just placed orders.

How to read UTM data for affiliates

Once your links are live, check your reports regularly. In Shopify, the "Sessions by referrer" report in Analytics lets you add UTM columns and filter by them. In GA4, the traffic acquisition reports let you view source, medium and campaign.

Useful views for an affiliate program:

By medium: total affiliate traffic compared with other channels.
By source: sessions and conversions per affiliate.
By content: which post formats (video, story, chat) bring buyers.
By campaign: how each promotion performed.

Look at trends, not single days. One viral post can spike traffic for a day and then fade. A steady affiliate who brings a few buyers every week can be worth more over time.

A simple UTM template you can copy

Use this as a typical starting point for your affiliate links:

utm_source = affiliate handle or ID (for example aff_1042)
utm_medium = affiliate
utm_campaign = affiliate_program (or the promotion name)
utm_content = where it is posted (tiktok, instagram, whatsapp, youtube, blog)
plus your referral code, for example ref=SARA10

Example:

https://yourstore.com/products/face-serum?utm_source=aff_1042&utm_medium=affiliate&utm_campaign=affiliate_program&utm_content=instagram&ref=SARA10

If you are setting up a program from scratch, our step-by-step guide on how to start a Shopify affiliate program covers the rest of the setup.

How Taguu helps

Taguu is a Shopify affiliate app built for COD stores. It handles UTM links for you:

Affiliates get links for any product with UTM parameters and their ref code already added. The merchant can also create an optional coupon code per affiliate.
Attribution checks the affiliate coupon first, then the UTM last click, then a referral cookie saved on the cart, so it works with COD form apps. The last affiliate click wins.
Commissions stay pending until the order is delivered (and paid for COD) plus a hold period (default 7 days). Cancelled, refused, returned and refunded orders are reversed automatically.

There is a Free plan for up to 50 affiliate orders a month and 0% fee on sales on every plan. You can install Taguu and try it on your store.

FAQ

Do UTM parameters affect SEO?

UTM parameters are meant for tracking, not ranking. Affiliate links are usually shared on social media and in chats rather than used as links from your own pages. To be safe, do not use UTM links in your own site navigation, and make sure your product pages have a canonical URL (Shopify themes usually set this).

Are UTM parameters case sensitive?

In GA4, UTM values are case sensitive, so Affiliate and affiliate appear as different values. Use lowercase for every value to keep your reports clean.

Can I track affiliate sales with UTMs only?

You can see traffic and some conversions, but UTMs alone are not reliable for paying commission. They disappear when a shopper returns later without the link. Combine UTMs with a referral code, a cookie and coupon codes.

Should every affiliate have a unique utm_source?

Yes. A unique utm_source for each affiliate lets you compare partners side by side. Use their handle or an ID that will not change if they rename their social account.

What utm_medium should I use for affiliates?

Use one fixed value, such as affiliate, for every affiliate link. This keeps all affiliate traffic grouped together so you can compare it with your other channels.

UTM Parameters for Affiliate Links: A Simple Guide for Shopify Stores