How is conversion tracking implemented (cookie, tag, UTM)?

Getting credit for email-driven conversions requires connecting the click (which happens in email) to the conversion (which usually happens on your website). That connection relies on three main mechanisms, often used together.

UTM parameters. You tag your email links with URL parameters like ?utm_source=email&utm_medium=newsletter&utm_campaign=march2024. When subscribers click and land on your site, your analytics tool (Google Analytics or similar) captures these parameters and attributes the session to email. Any conversion that happens in that session gets credited to the email campaign. This is the most widely used approach and the easiest to set up.

Cookies. When a subscriber clicks your tracking URL and arrives on your site, a cookie can be set on their browser storing the campaign information. If they convert later (even after leaving and returning), the cookie links the conversion back to the email. Cookie-based attribution has a defined window, typically 7-30 days. After that, the cookie expires and late conversions go uncredited.

Conversion tags. JavaScript tags on your website fire events when specific actions occur (purchase confirmed, form submitted, etc.). These tags talk to your analytics or ad platform to record the conversion. Most ecommerce platforms and CMSes have these built in or installable as plugins.

Each method has gaps. Cookies break across devices. UTMs are lost if the subscriber navigates away and returns directly. Tags require accurate implementation on every conversion page. Cross-device journeys are particularly hard to track because browsers can't share cookies. The result is that email attribution is almost always an undercount of email's real contribution to revenue.

If you're setting this up from scratch, start with UTMs on all your email links, then add a sensible attribution window in your analytics platform that matches your typical purchase cycle.