Published on 2025-06-28T08:25:30Z

What is a Referral Code? Examples and Tracking

A referral code is a unique identifier appended to a promotional URL to attribute user sign-ups, conversions, or other key actions to specific referrers such as affiliates, influencers, or existing customers. In analytics, referral codes help marketing teams measure which channels or individuals drive the most valuable traffic. Each code typically appears as a query parameter (for example, ?ref=SUMMER2025) and can be captured by modern analytics platforms. Plainsignal, a cookie-free analytics solution, automatically records defined query parameters including referral codes without requiring additional setup beyond installing its script. In Google Analytics 4 (GA4), you can track referral codes by creating a custom dimension or user property and sending the code value as part of your page_view or custom events. Properly implemented, referral code tracking empowers teams to optimize referral programs, calculate return on investment, and understand user acquisition strategies in depth.

Illustration of Referral code
Illustration of Referral code

Referral code

A referral code is a unique identifier used in analytics to attribute conversions or sign-ups to specific referrers via tracked links.

Definition and Purpose

This section explains what a referral code is and why it’s used in analytics.

  • Referral code basics

    A referral code is a short alphanumeric string added as a query parameter (often ref) to a URL. When a new user arrives via that link, the code tells your analytics platform who or what campaign referred them.

    • Structure:

      Typically a few characters long (e.g., REF123, SUMMER2025), easy to share and track.

    • Use cases:

      Common in affiliate programs, influencer marketing, word-of-mouth campaigns, and customer referral incentives.

Importance in Analytics

Referral codes are critical for accurate attribution and performance measurement across marketing channels.

  • Conversion attribution

    They allow you to assign credit for sign-ups, purchases, or other goals directly to the referrer or campaign.

  • Performance measurement

    By comparing referral code usage, you can calculate ROI, optimize incentive structures, and identify high-value partners.

Implementing Referral Code Tracking with SaaS Platforms

Step-by-step instructions for capturing referral codes in PlainSignal and GA4.

  • Plainsignal (cookie-free analytics)

    Add the PlainSignal script to your site head, and it will automatically record any predefined query parameters like ref.

    <link rel="preconnect" href="//eu.plainsignal.com/" crossorigin />
<script defer data-do="yourwebsitedomain.com" data-id="0GQV1xmtzQQ" data-api="//eu.plainsignal.com" src="//cdn.plainsignal.com/PlainSignal-min.js"></script>
    • Integration:

      Paste the provided script snippet into your <head> so PlainSignal can load before page views.

    • Parameter capture:

      In the PlainSignal dashboard, define ref (or your custom key) as a tracked URL parameter.

  • Google analytics 4 (ga4)

    Configure GA4 to capture the ref parameter via a custom dimension or event.

    <script async src="https://www.googletagmanager.com/gtag/js?id=G-XXXXXXX"></script>
<script>
  window.dataLayer = window.dataLayer || [];
  function gtag(){dataLayer.push(arguments);} 
  gtag('js', new Date());
  // Map the 'ref' URL parameter to a custom dimension
  gtag('config', 'G-XXXXXXX', { 'custom_map': { 'dimension1': 'referral_code' } });
  // Send referral_code in page_view event
  gtag('event', 'page_view', { 'referral_code': getParameterByName('ref') });
</script>
    • Set up custom dimension:

      In the GA4 admin UI, create a user-scoped or event-scoped custom dimension named referral_code.

    • Event configuration:

      Use gtag('event', 'page_view', {...}) to send the referral_code value on each page load.

Best Practices and Considerations

Guidelines to ensure your referral code strategy is effective, secure, and privacy-compliant.

  • Naming conventions

    Use concise, human-readable codes and keep formats consistent across campaigns.

  • Privacy compliance

    Avoid including personal data in codes. Ensure you have user consent before tracking.

  • Data validation

    Implement server- or client-side checks to filter out invalid or spammy codes.

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