To track affiliate links in email, add unique UTM parameters to each link, use your affiliate platform’s tracking IDs, and analyze the results in your analytics dashboard — this tells you exactly which emails, placements, and campaigns drive the most clicks and commissions.
You’ve sent your affiliate newsletter to thousands of subscribers, and sales come in — but you have no idea which email drove the sale, whether your subject line made a difference, or if a particular call-to-action converted better. Without tracking, you’re essentially guessing what works.
In this guide, you’ll learn exactly how to track affiliate links in email, from adding UTM parameters to using affiliate sub-IDs, analysing email click data, and optimising based on real performance.
TL;DR
Track affiliate links in email by adding UTM parameters (utm_source=newsletter, utm_medium=email, utm_campaign, and utm_content to identify specific placements). For affiliate-specific tracking, use subid or tid parameters supported by your affiliate platform. Most email marketing tools provide click tracking data showing which links were clicked. The analytics dashboard from your email service provider tells you who clicked, while your affiliate dashboard tells you who bought — combining these two is how you find the full picture.
Key Takeaways
- UTM parameters are the universal tracking standard for email — use utm_medium=email to identify email traffic in Google Analytics, and utm_content to distinguish different links within the same email.
- Affiliate sub-IDs or tracking IDs let you see performance at the link level within your affiliate dashboard, not just in Google Analytics.
- Each email placement needs a unique identifier — the header link, in-text link, and button CTA should all have different utm_content values so you can see which placement performs best.
- Email open tracking uses invisible pixels and is a strong engagement signal rather than an exact count — click tracking is more precise because it records a deliberate action.
How to Track Affiliate Links in Email: The Complete Process
Tracking affiliate links in email marketing involves three distinct steps: creating trackable links, monitoring clicks, and connecting clicks to conversions.
Step 1: Add UTM Parameters to Your Affiliate Links
UTM (Urchin Traffic Module) parameters are the gold standard for email tracking. When someone clicks your affiliate link, these tags tell Google Analytics exactly where the traffic came from.
The essential UTM parameters for email are:
| Parameter | What It Tracks | Example Value | Required? |
|---|---|---|---|
| utm_source | Where the traffic comes from | newsletter, weekly-email | Yes |
| utm_medium | The type of channel — always use email | Yes | |
| utm_campaign | The specific email or promotion | weekly-digest, june-sale | Yes |
| utm_content | Which link placement within the email | header-link, button-cta, in-text | Optional |
Building Your Tracked Link
Start with your standard affiliate link, then add the parameters:
https://example.com/ref/your-id?utm_source=newsletter&utm_medium=email&utm_campaign=weekly-digest&utm_content=header-link
For example, if you’re promoting a product in a weekly newsletter and the link appears in both the header and the main text, each link gets a different utm_content value:
- Header link: utm_content=header-link
- In-text link: utm_content=in-text
- Button CTA: utm_content=button-cta
This tells you which placement drives the most clicks and conversions.
Best Practices for UTM in Email
- Use lowercase consistently — analytics tools are case-sensitive. “Newsletter” and “newsletter” are treated as different sources.
- Replace spaces with hyphens — “weekly digest” becomes “weekly-digest”.
- Don’t use UTM on internal links — only on external affiliate links that point to merchant sites.
- Document your naming convention — maintain a spreadsheet of approved source names, medium types, and campaign naming patterns.
Step 2: Add Affiliate-Specific Tracking IDs
UTM parameters work with Google Analytics, but your affiliate platform may not pass that data through to your dashboard. That’s where affiliate sub-IDs or tracking IDs come in.
Most affiliate networks support custom parameters like subid, tid (tracking ID), or clickid. These appear directly in your affiliate dashboard reports.
Format your link like this:
https://example.com/affiliate?tid=weekly-digest-header
Check your affiliate platform’s documentation — some networks use aff_sub, others use subid, and some allow you to define custom parameters. For example, Post Affiliate Pro’s UTM builder supports creating campaign-specific URLs with source, medium, and campaign parameters.
If you’re using a platform like SamCart, affiliates can add UTM parameters to their affiliate links, which are then captured when an order is placed and stored with the order record.
Step 3: Use Your Email Service Provider’s Click Tracking
Most email marketing platforms (Mailchimp, Klaviyo, ConvertKit, etc.) provide built-in click tracking that shows you which links were clicked in each email.
Here’s what email click tracking typically includes:
- Total clicks per link — how many subscribers clicked each affiliate link.
- Unique clicks — the number of individual subscribers who clicked, excluding multiple clicks from the same person.
- Click-through rate (CTR) — the percentage of recipients who clicked.
- Sent-opened-clicked funnel — shows how many recipients opened each email and how many clicked a link inside it.
- Recent recipients — who clicked which link, useful for identifying engaged subscribers.
For example, with Referly, email tracking runs automatically and shows a funnel with three steps: Sent, Opened, and Clicked.
Open tracking uses a tiny invisible image embedded in the email. When the email is viewed, the image loads and counts as an open. Some email apps block or preload images, so open rates are a strong engagement signal rather than an exact count. Click tracking is more precise since it records an actual action the recipient took.
Step 4: Combine Click and Conversion Data
Here’s where everything comes together. You now have three sources of data:
- Email analytics — tells you which links got clicks.
- Google Analytics — shows you email traffic by source, medium, campaign, and content.
- Affiliate dashboard — tells you which links generated sales.
By using unique identifiers across all three, you can connect clicks to conversions:
- Your email click data shows Link A got 100 clicks.
- Your affiliate dashboard shows Link A generated 5 sales.
- Your conversion rate for Link A is 5%.
This is how you know which emails, placements, and campaigns actually drive revenue.
Step 5: Analyse and Optimise
Once you have data, look for patterns:
- Which email sent the most clicks? — compare different newsletters or email types.
- Which link placement converted best? — compare the header link vs. the button CTA.
- Which campaign had the highest conversion rate? — is there a type of offer or product that performs better?
- What’s the click-to-sale time? — do most sales happen immediately or after a delay?
Common Affiliate Link Tracking Mistakes in Email
- Using the same link for multiple placements — you can’t tell which CTA performed best. Add utm_content to distinguish them.
- Inconsistent naming conventions — “newsletter” in one email, “weekly-digest” in another. Fragmenting your analytics.
- Not using utm_medium=email — if you don’t set the medium, email traffic may appear as “direct” or “referral” in analytics.
- Forgetting to test links — always click your tracked links before sending to verify tracking works and the destination is correct.
- Over-tagging — long tracked links can look messy. Use a URL shortener while preserving UTM parameters.
Email Deliverability and Affiliate Links
Tracking is useless if your emails don’t reach the inbox. Two critical factors affect deliverability for affiliate emails:
Link Reputation
If your affiliate link points to a domain with a poor reputation, email filters may flag your message. Use branded short links (like links.yourbrand.com/offer) instead of generic shorteners. Branded links build trust with both subscribers and email providers.
SPF, DKIM, and DMARC Alignment
Email authentication is essential for affiliate emails. If your SPF and DKIM records aren’t aligned with the domain in your “From:” address, bulk email filters may treat your promotions as suspicious and send them to spam or reject them entirely.
This is particularly important when affiliates are sending emails on your behalf through multiple ESPs. Gmail explicitly states that authenticated messages are less likely to be rejected or marked as spam, and mass senders should implement all three authentication methods.
Frequently Asked Questions
How do I track affiliate link clicks in email?
Use UTM parameters (utm_source, utm_medium=email, utm_campaign, and utm_content) on your affiliate links, then view click data in Google Analytics or your email service provider’s analytics. Your affiliate dashboard will also show conversions from those links if you use sub-IDs.
What’s the difference between email open tracking and click tracking?
Open tracking uses an invisible image pixel that loads when the email is viewed — some email providers block images, so opens are a signal rather than an exact count. Click tracking records when a recipient actually clicks a link, which is more precise since it’s a deliberate action.
Can I track affiliate links in email without Google Analytics?
Yes. Most email service providers include built-in click tracking that shows which links were clicked. Additionally, affiliate platforms often provide click and conversion data in their dashboards. You can also use a URL shortener with analytics to track clicks.
Why don’t my email link clicks match my affiliate dashboard conversions?
Some subscribers click but don’t buy. Others may buy later using a different device or after revisiting the site directly. Reporting delays on some affiliate platforms can also cause mismatches. UTM parameters and sub-IDs help connect clicks to conversions more accurately.
What should I put in utm_source for email?
Use the name of your newsletter or email type — for example, weekly-digest, welcome-series, or flash-sale. This lets you compare performance across different email campaigns.
Do shortened affiliate links lose tracking data?
No — if your short link redirects to your full, UTM-tagged URL, all tracking parameters are preserved. The shortener simply masks the length while keeping the tracking intact. Always redirect the shortened URL to your tagged URL, never the reverse.
Sources
- AffiliateTracker — UTM and Link Tracking for Email
- Shield Stack — Affiliate Link Tracking in Email
- Post Affiliate Pro — UTM Builder and Best Practices
- SamCart — Tracking UTM Parameters
- Referly — Email Open and Click Tracking
- PowerDMARC — Email Authentication for Affiliates
Have a specific email affiliate tracking challenge or platform you’d like help with? Drop your question in the comments — we’re here to help you maximise your affiliate email performance.
