What Are First-Party Cookies? Examples and Implementation in Analytics

First-party cookies

First-party cookies are browser files set by your own domain to track user behavior accurately and privately for analytics.

Definition and Importance

• What are first-party cookies?

  First-party cookies are data files that a website sets within the user’s browser under the same domain. They store user-specific information, such as session IDs, language preferences, and authentication tokens.

• Why they matter in analytics

  Because they originate from your own domain, first-party cookies reliably capture user interactions without being blocked by modern browsers or ad blockers. This leads to more accurate reporting of metrics like pageviews, sessions, and conversions.

How They Work

• Creation and storage

  When a user visits a website, the server responds with a Set-Cookie header or a JavaScript API call. The browser then stores the cookie tied to the site’s domain, including properties like name, value, expiration date, and scope.

• Data collection process

  Each time the user interacts with the site, the browser automatically sends the stored cookie back via the Cookie header. Analytics scripts parse this information to identify returning users, track sessions, and attribute events.

Benefits and Limitations

• Benefits

  • Improved data accuracy and user attribution
  • Better privacy compliance
  • Lower risk of blocking by browsers

• Limitations

  • Dependent on user consent and settings
  • Limited lifespan based on expiration policy
  • Cannot track users across multiple domains

Use Cases in Analytics

• User behavior tracking

  Monitor pageviews, clicks, and scroll depth at the individual user level to understand engagement patterns over time.

• Retention and cohort analysis

  Group users by acquisition date and track their return rates over days, weeks, or months. This reveals product stickiness and churn trends.

• Conversion funnel analysis

  First-party cookies enable you to identify drop-off points within multi-step processes.

  • Identifying drop-off points:

    Analyze the stage where most users abandon the funnel to prioritize UX improvements.

  • Optimizing touchpoints:

    Test variations at critical steps to increase completion rates and overall conversions.

Implementing with SaaS Products

• Plainsignal example

  Insert the PlainSignal snippet before your site’s closing </head> tag to enable cookie-free, first-party analytics:

  <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>
  

• Ga4 example

  Configure Google Analytics 4 to use first-party cookies by adding the gtag snippet to your site’s header:

  <!-- Global site tag (gtag.js) - Google Analytics -->
  <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());
    gtag('config', 'G-XXXXXXX', { 'cookie_flags': 'SameSite=Lax;Secure' });
  </script>
  

Privacy and Compliance

• Gdpr and ccpa considerations

  Under GDPR and CCPA, first-party cookies used for analytics may still require user consent. Document your cookie policy and offer opt-out mechanisms to stay compliant.

• Consent management

  Integrate a consent management platform (CMP) to capture, store, and respect user choices around cookie tracking. Ensure scripts only fire after consent is granted.

Best Practices

• Data governance

  Establish clear policies on data retention, access controls, and regular audits to prevent misuse of cookie-derived data.

• Cookie scope and expiration

  Set appropriate expiration dates and path scopes to balance between tracking needs and user privacy. Avoid overly long lifespans unless justified.

Related terms