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What is Attribution?

When a user visits your site, they rarely come from a single source. They might discover your product through a Google Ad, leave, come back from an email campaign, and finally convert through a direct visit. Attribution is how you decide which of those touchpoints gets the credit for the conversion. The CMS script’s cms_rf parameter-based cookie system is a lightweight, first-party implementation of this concept no third-party dependencies, no cross-domain complexity, just clean URL-parameter tracking stored directly in the browser.
The CMS script uses last-click attribution by default.
On page load, the CMS script checks the URL for the cms_rf parameter. If present, it runs attribution logic that either sets the cookie for the first time or updates an existing value.
1

User arrives on site

The user clicks a link with ?cms_rf=google_cpc appended to the URL (e.g., from a paid ad, email, or affiliate link).
2

Script detects cms_rf

The CMS script reads the cms_rf value from url on page load.
3

Cookie logic runs

Based on the attribution model, the script either sets the cookie (if not set) or overwrites it (if already set).
4

Cookie is sent with conversion

When the user completes a conversion event, the cms_rf cookie value is read and passed along to your analytics or CRM system.
The cms_rf cookie is a first-party cookie, which means it lives in the user’s browser under your own domain. This makes it more reliable than third-party tracking pixels in an era of increasing browser privacy restrictions (Safari ITP, Firefox ETP, etc.).

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First-Click Attribution

In first-click, the first touchpoint that introduced the user is retained. Once the cms_rf cookie is set, it is not overwritten even if the user returns later with a different cms_rf value.

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Example scenario

First-click is most useful when the initial discovery channel is the signal you want to report on (often longer consideration cycles like SaaS, B2B, or high-ticket products).

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When to use First-Click

  • You want to understand what drives awareness and top-of-funnel traffic.
  • You want credit to remain with the first recorded source across return visits.
  • Your customer journey typically spans multiple sessions before conversion.

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Last-Click Attribution

In last-click, the most recent touchpoint is retained. Every time a user arrives with a new cms_rf value, the cookie is overwritten. So the stored value reflects the last channel seen before converting.

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Example scenario

Last-click is most useful when the final converting touchpoint is the signal you want to report on (often performance and conversion-focused workflows).

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When to use Last-Click

  • You want to know what closes deals and drives final conversions.
  • You want the attribution value to reflect the most recent recorded source before conversion.
  • Your customer journey is short and straightforward.

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Which Model is Better?

There’s no universally “better” model. Each answers a different question.
  • Your primary marketing goal is brand discovery and awareness
  • You run significant spend on top-of-funnel channels (paid search, content, social) and need to justify ROI
  • Your conversion cycle is 30+ days
  • You’re trying to understand what channel to invest in to grow your audience

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Summary

Both models are simple, privacy-friendly, and effective when used for the right purpose. The most important thing is to choose deliberately based on your analytics goals and document which model is active so your team interprets the data correctly.