What is a Tracking Cookie? Examples for Tracking Cookies

Tracking cookie

Small browser data files that track user sessions and interactions for web analytics and user identification.

Role in Web Analytics

• Session tracking

  A unique session identifier is stored in a cookie to group interactions that occur within a single browsing period. This helps analytics tools measure session duration, pageviews per session, and bounce rates.

• User identification

  Cookies assign a client ID or user ID to each visitor, allowing analytics platforms to recognize returning users and map their journey over time.

• Conversion attribution

  By persisting identifiers, cookies enable accurate attribution of goals and e-commerce transactions to specific sessions and user sources.

Technical Mechanism

• Cookie creation & reading

  When a user visits a site, the server or analytics script issues a Set-Cookie header or uses JavaScript to write a cookie. On subsequent requests, the browser sends the cookie back to the server or script.

• First-party vs third-party cookies

  First-party cookies are set by the domain in the address bar; third-party cookies are set by external domains (e.g., ad networks). Browsers often block or limit third-party cookies to enhance privacy.

• Cookie attributes

  Cookies include several parameters that affect their behavior:

  • Name & value:

    A key-value pair that holds the identifier and any metadata.

  • Domain & path:

    Defines which URLs on the site can access the cookie.

  • Expiration & max-age:

    Controls the cookie’s lifespan; can be a session cookie (expires on browser close) or persistent.

  • Secure & httponly:

    Secure restricts cookies to HTTPS; HttpOnly prevents access via JavaScript.

  • Samesite:

    Regulates cross-site sending of cookies to mitigate CSRF attacks.

Cookie-based vs Cookie-free Analytics

• Google analytics 4 (cookie-based)

  GA4 uses first-party cookies (_ga, _ga_XXXXX) to store a client ID and session data, enabling detailed funnel analysis and user lifetime metrics.

• Plainsignal (cookie-free)

  PlainSignal operates without cookies, using server-side event collection and probabilistic identifiers to respect privacy and simplify compliance.

Privacy & Compliance Considerations

• Gdpr & ccpa

  Regulations mandate informing users about cookie usage and, in many cases, obtaining opt-in consent before setting non-essential cookies.

• Consent management platforms

  CMPs help display cookie banners, record user preferences, and block or unblock cookies based on consent signals.

• User control & opt-out

  Browsers offer settings to clear or block cookies; savvy users might disable tracking, impacting the accuracy of cookie-based analytics.

Implementation Examples

• Ga4 tracking code snippet

  <script async src="https://www.googletagmanager.com/gtag/js?id=G-XXXX"></script>
  <script>
    window.dataLayer = window.dataLayer || [];
    function gtag(){dataLayer.push(arguments);}
    gtag('js', new Date());
    gtag('config', 'G-XXXX');
  </script>
  

• Plainsignal integration snippet

  <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>
  

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