create a funnel using Google Flights as source of traffic (gclsrc=gf?)
Hi! I’m building a funnel for traffic coming from Google Flights. The unique parameter that appears in the URL coming from them is gclsrc=gf.
How can i create a funnel using the source of traffic this parameter?
Detailsidentifying_conversions
The short answer is:
You should utilize the Google Analytics Measurement Protocol to establish a robust, server-side tracking funnel that correctly attributes conversions originating from Google Flights traffic identified by the gclsrc=gf URL parameter.
The initial identification of this parameter and the corresponding client ID (CID) is handled in the browser via Google Tag Manager (GTM) and a Google Cloud Platform (GCP) or Stape server container.
This setup allows you to pass the gclsrc=gf value and the CID (which is essential for user-level attribution) to your server, then use the Measurement Protocol to send delayed or enhanced conversion events to Google Analytics 4 (GA4).
This method ensures reliable conversion attribution, bypassing common client-side tracking limitations like ad blockers and browser restrictions, thus guaranteeing the accuracy of your Google Flights funnel analysis.
The long answer is:
The core of your solution lies in moving your Google Flights conversion tracking from the unreliable client-side to a server-side architecture, leveraging the Google Analytics Measurement Protocol for data transmission.
This approach is necessitated by the requirement to accurately track a specific traffic source identified by the non-standard gclsrc=gf parameter and ensure that all subsequent conversion events are correctly attributed to that initial session.
The process begins on the client-side: when a user lands on your site with the gclsrc=gf parameter, GTM is used to read this URL parameter and the Google Analytics Client ID (CID).
The CID is the key component for linking server-side events back to the original client-side session.
GTM then sends this data, along with a PageView or other initial event, to your server-side tracking endpoint hosted on a platform like Stape or GCP.
The real technical advantage comes in the server container.
Here, you capture the incoming request, the gclsrc=gf value, and the unique CID.
You can then use the server environment to process subsequent conversion events, such as AddToCart or Purchase, and send them directly to GA4 using the Google Analytics Measurement Protocol (a set of rules for constructing HTTP requests to send raw user interaction data to Google Analytics).
Because the server-side requests include the original CID and the gclsrc=gf context, GA4 correctly attributes the conversion to the Google Flights source, effectively building your desired funnel.
The Measurement Protocol is ideal for this because it allows for delayed or non-web event reporting, ensuring that even if a conversion happens hours after the initial click (e.g., an offline purchase following a flight search), it’s linked back to the correct source, which is the definition of creating a robust funnel.
This is highly cost-effective because it utilizes free or low-cost tools like GTM and server-side tagging (especially with a service like Stape) to solve a fundamental attribution problem, eliminating the need for expensive third-party custom data collection or complex database synchronization.
To further enhance your data utility, you should integrate the BigQuery API to export your raw, clean GA4 event data into BigQuery.
Once in BigQuery, you can use the Looker Studio API to build custom, highly detailed funnel visualizations and reports that directly pull from this server-validated conversion data, allowing for deeper analysis of the Google Flights traffic performance beyond the standard GA4 interface limitations.
This BigQuery plus Looker Studio integration provides unparalleled flexibility and drill-down capability, turning your raw funnel data into actionable marketing intelligence.
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