What are URL Parameters? Examples and Best Practices

Url parameters

Key-value pairs appended to URLs for tracking, campaign attribution, and passing data to analytics tools like GA4 and Plainsignal.

Overview of URL Parameters

• Definition

  A URL parameter is a data point in the form key=value appended to the end of a URL to transmit information.

• Use cases

  URL parameters power various use cases including:

  • Campaign attribution and tracking
  • A/B testing and feature flags
  • Content personalization based on user segments

• Basic structure

  The basic structure of URL parameters consists of a query string and key-value pairs.

  • Query string separator:

    The question mark (?) marks the beginning of URL parameters.

  • Key-value pair format:

    Each parameter follows the key=value format, with multiple pairs joined by an ampersand (&).

Using URL Parameters in Analytics

• Campaign tracking (utm parameters)

  UTM parameters are standardized tags (utm_source, utm_medium, utm_campaign, etc.) recognized by GA4 and many other analytics platforms for tracking marketing campaigns.

  • Example url:

    https://example.com/landing-page?utm_source=newsletter&utm_medium=email&utm_campaign=summer_sale

• Custom parameters

  Custom parameters let you collect additional data beyond UTM tags, such as user IDs, session IDs, or feature flags. These parameters can be read by PlainSignal or forwarded to GA4 as custom dimensions.

Implementation Examples

• Plainsignal code snippet

  Insert PlainSignal’s cookie-free analytics script into your HTML to automatically collect URL parameters and send them as event properties.

  • Tracking script:

    <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>
    

  • How it works:

    PlainSignal parses window.location.search to extract URL parameters and transmits them server-side without relying on cookies.

• Ga4 example configuration

  Use the gtag.js library to read URL parameters via JavaScript and pass them to GA4 as configuration or event parameters.

  • Code example:

    <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());
      const urlParams = new URLSearchParams(window.location.search);
      gtag('config', 'G-XXXXXXX', {
        'campaign_source': urlParams.get('utm_source'),
        'campaign_medium': urlParams.get('utm_medium')
      });
    </script>
    

  • Notes:

    Ensure that the custom parameter keys match the custom dimensions configured in your GA4 property.

Best Practices and Common Pitfalls

• Naming conventions

  Use clear, lowercase, and consistent parameter names to avoid duplication and confusion.

• Proper encoding

  Apply URL encoding (percent-encoding) to parameter values to handle spaces and special characters correctly. For example, a space becomes %20.

• Avoid sensitive data

  Never pass personally identifiable information (PII) or confidential data in URL parameters, as URLs may be logged or exposed in referrers.

Related terms