Published on 2025-06-28T06:33:34Z

What is a Query String? Examples in Analytics

A query string is the component of a URL that follows the question mark (?) and contains one or more parameters formatted as key–value pairs, separated by ampersands (&). In web analytics, query strings are extensively used to convey campaign data (e.g., UTM parameters), personalize content, enable A/B testing, and stitch together user sessions without relying solely on cookies. Platforms like Plainsignal (a cookie-free, privacy-focused analytics solution) and Google Analytics 4 (GA4) automatically parse query string parameters to attribute traffic sources, measure campaign performance, and segment audiences. Because these parameters are part of the URL, they must be properly encoded and managed to maintain data accuracy and protect user privacy. The following sections break down the structure of query strings, illustrate their use in Plainsignal and GA4, and outline best practices for secure and effective tracking.

Illustration of Query string
Illustration of Query string

Query string

Key-value pairs appended to a URL after ‘?’, used in analytics to track campaigns, personalize content, and more.

Breaking Down a Query String

Query strings consist of structured elements that together pass data through URLs. Understanding each component is essential for accurate tracking and parsing in analytics.

  • Parameter name

    The key in a key–value pair (e.g., utm_source, session_id) that represents the variable being passed.

  • Parameter value

    The data assigned to a parameter name (e.g., google, 12345) which conveys specific information.

  • Delimiters

    Parameters follow the question mark (?) and are separated by ampersands (&). Each key–value is joined by an equals sign (=).

  • Example

    A typical query string example:

    ?utm_source=google&utm_medium=cpc&utm_campaign=spring_sale

Why Query Strings Matter in Analytics

Analytics platforms rely on query string parameters to enrich user and campaign data. This makes it possible to attribute traffic, tailor user experiences, and measure the ROI of marketing efforts.

  • Campaign attribution

    Assigns traffic to specific marketing channels or campaigns using parameters like utm_source, utm_medium, and utm_campaign.

  • Content personalization

    Dynamically serves or customizes content based on parameters in the URL, improving user relevance and engagement.

  • A/b testing

    Segments traffic into test variants by adding test identifiers to the query string, enabling split-test analysis.

  • Session stitching

    Links user activity across subdomains or systems by passing unique session IDs in the URL.

Query Strings with Plainsignal (Cookie-free Analytics)

PlainSignal captures query string parameters without cookies by reading them at page load via a lightweight script. This approach maintains user privacy while still allowing detailed campaign tracking.

  • Implementation

    Add PlainSignal’s tracking snippet to your HTML (ideally in the <head>):

    <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>

    Query parameters appended to your URLs will be automatically captured and visualized in the PlainSignal dashboard.

  • Advantages

    No cookies or client-side storage required, reducing privacy concerns. Simple to set up and lightweight for fast load times.

  • Considerations

    Since data is exposed in the URL, ensure no sensitive information is passed. Monitor URL length limits to avoid truncation.

Using Query Strings in Google Analytics 4

GA4 automatically captures standard UTM parameters and allows custom parameters for advanced reporting. Proper setup ensures precise attribution and analysis.

  • Utm tracking

    GA4 recognizes five standard UTM parameters to attribute campaigns.

    • Predefined utm parameters:

      GA4 automatically processes utm_source, utm_medium, utm_campaign, utm_term, and utm_content.

    • Custom campaign parameters:

      Use the Admin > Data Streams > More tagging settings to register additional parameters for reporting.

  • Custom parameters

    Define event-level custom parameters via gtag.js or Google Tag Manager. Append them in the query string or include them in event configuration.

  • Reporting in ga4

    Analyze campaign performance in the Traffic Acquisition report. Use Explorations to create custom segments based on query parameters.

Best Practices and Security Considerations

Maintain data integrity and user privacy when using query strings by following these guidelines.

  • Encode parameters

    URL-encode special characters (e.g., spaces as %20) to prevent parsing errors.

  • Avoid sensitive data

    Never include personal or confidential information (e.g., PII, tokens) in query strings.

  • Limit length

    Keep URLs concise; long query strings may be truncated by browsers or servers.

  • Consistent naming

    Use a standardized parameter naming convention (e.g., all lowercase, underscores) to avoid fragmentation in analytics.

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