How GA4 Tracks Traffic from Perplexity Comet and ChatGPT Atlas

Understanding how website traffic tracking works is vital for anyone running a digital presence. If you use the analytics tool Google Analytics 4 (GA4), you should know how emerging platforms like Perplexity Comet, and ChatGPT Atlas impact your data. 

Here we will show you how website traffic tracking changes when users come through those tools, how GA4 handles it, and what you can do to stay accurate.

What happens when AI-powered browsers send traffic

Website traffic tracking becomes more complex when users arrive through AI-powered browsers like Perplexity Comet and ChatGPT Atlas. These tools change how referral data is passed to your analytics system.

Perplexity Comet often behaves like a standard browser and passes a visible referrer header. In GA4, this means the session usually appears with a clear source, such as perplexity.ai, and a medium labeled referral. You can analyze it under Traffic acquisition reports to measure how many visitors are coming from that channel and how they engage with your pages. Over time, this helps you identify whether Perplexity is driving high-quality visits or casual exploration.

ChatGPT Atlas, on the other hand, is less predictable. It opens shared links in an internal sandbox or webview, which strips the referrer header entirely. In that case, GA4 logs the session as “Direct” or marks it as (not set) in your reports. This makes attribution harder because those sessions blend with visitors who type your URL manually or click from saved bookmarks.

These tracking gaps create noise in your reporting. Without configuration updates, your website traffic tracking in GA4 may underestimate referral traffic from AI-driven discovery platforms. Adjusting your setup ensures your analytics reflect how users truly find and access your content.

How GA4 handles referrals from these tools

Referrer and medium in GA4

When you open the acquisition reports in GA4, the Session source/medium metric shows where your users came from and how they reached your website. If a user clicks a link from Perplexity Comet and the browser passes a referrer header, GA4 correctly tags the session with perplexity.ai / referral. This makes it easy to measure visitor behavior, engagement rate, and conversions tied to that AI browser.

If the link comes from ChatGPT Atlas, things change. The platform often loads pages inside its own container or sandbox environment. This process strips the referrer information before it reaches your site. As a result, GA4 records the visit as Direct or marks it as (not set), mixing it with users who enter your URL manually or access it from bookmarks.

This difference matters because it affects attribution accuracy. You might think your Direct traffic is growing, when in reality a portion of those visits comes from AI browsing tools. Recognizing this helps you make smarter marketing and content decisions.

Why referrers disappear

Several technical issues can interfere with website traffic tracking and cause missing or incorrect referrer data:

• Embedded webviews. Some AI-powered tools use embedded browsers that suppress or rewrite the referrer header before the request hits your server.
• HTTPS to HTTP transitions. Moving from a secure page to a non-secure one strips the referrer by default, leaving GA4 without context for where the visitor came from.
• Privacy-focused settings. Browsers and AI tools increasingly adopt tracking-prevention features or sandbox modes that intentionally block referrer details to protect user privacy.
• URL shorteners or redirect chains. When traffic passes through multiple redirects, referrer data can be lost along the way, causing incomplete session tracking.

Each of these factors can distort your GA4 acquisition data. If referrers vanish, your reports will not accurately show how visitors are discovering your content, and that weakens your understanding of user intent and marketing performance.

Setting up GA4 for better website traffic tracking

Accurate website traffic tracking depends on how well your analytics system is configured. Since AI-based tools like Perplexity Comet, and ChatGPT Atlas can obscure or alter referral data, you need to refine your GA4 setup to ensure data integrity. 

The goal is to help GA4 recognize these visits as distinct traffic sources rather than blending them into generic “Direct” sessions.

Create a custom channel group

In GA4, you can define new channel rules to classify AI-related traffic correctly.

1. Go to Admin → Data settings → Channel groups.
2. Select Create new channel group.
3. Name it “AI Tools” or something descriptive.
4. Add conditions under the Session source using regex patterns to detect known AI platforms, such as:
   
   • perplexity\.ai
   • chat\.openai\.com
   • poe\.com
5. Place this new channel above the “Referral” channel so GA4 prioritizes it.

This setup ensures that visits from these platforms are tracked under a unique category, giving you a clearer view of how AI browsers contribute to engagement and conversions.

Use UTM tagging for shared content

If your audience frequently shares your content through AI chat tools, use UTM parameters to maintain clean attribution.

For example:

?utm_source=chatgpt&utm_medium=ai_browser&utm_campaign=content_test

UTM tagging helps preserve the source even when the AI browser strips referrer data. It keeps your website traffic tracking consistent across different tools and prevents data loss in your GA4 reports.

Create audience segments for analysis

Once your channel is set up, build audience segments in GA4 specifically for “AI Tools.” Compare engagement metrics like average session duration, pages per session, and conversion rate against organic or social traffic. You might find that visitors from Perplexity Comet spend longer reading your content or that ChatGPT Atlas visitors bounce faster due to embedded viewing environments. This insight helps tailor your content strategy to each traffic source.

Monitor referral patterns and anomalies

Keep an eye on your acquisition trends over time. If you notice sudden spikes in “Direct” traffic or sessions from unknown referrers, investigate the URLs and devices used. These anomalies often indicate new AI platforms sending users your way. Updating your GA4 regex list regularly keeps your website traffic tracking accurate as new AI-powered browsers emerge.

Keep historical data consistent

When you create new channels or tagging rules, the changes apply only going forward. To keep past data useful, export existing acquisition data to a spreadsheet or visualization tool like Looker Studio. Label suspected AI-origin traffic manually to maintain consistency between old and new reports.

Why this matters for attribution

Accurate website traffic tracking affects how you allocate resources, measure conversion rates, and decide what content to invest in. If one of your discovery channels is an AI browser and it’s showing up as direct traffic in GA4, you’re missing insight.

For example:

• If Perplexity Comet drives significant traffic but GA4 logs it as a referral, you know which content resonates in that environment.
• If ChatGPT Atlas drives traffic, but it’s logged as direct, you might misattribute it to bookmarks or typed URLs. That leads to faulty strategy decisions.
  Treating those tools as separate channels helps you measure their impact and optimise for them.

Best practices for more reliable website traffic tracking

To get the most accurate website traffic tracking in GA4, follow these practical steps:

• Maintain a list of known AI-browser domains. Keep an updated list of domains like perplexity.ai, chat.openai.com, or any new AI browsing platforms your audience may use. Include these in your GA4 regex rules so traffic is consistently classified.
• Use UTM tagging for links likely shared via AI tools. Tagging ensures that even if the AI browser strips the referrer header, GA4 can still attribute the session correctly. Use clear utm_source and utm_medium values to distinguish AI-driven traffic from organic or social.
• Segment traffic by channel group in GA4. Once your custom “AI Tools” channel is set up, analyze key metrics such as session duration, pages per session, and conversion rates. Compare these to other channels to understand engagement patterns.
• Educate your team. Not all sessions labelled “Direct” are manual visits or bookmarks. Some traffic comes from AI-powered browsers that hide referral data. Ensuring everyone on your team understands this prevents misinterpretation of metrics and marketing decisions.
• Review session sources and mediums regularly. AI tools are constantly evolving. Periodically check GA4 reports to identify new domains, and update your regex rules to capture traffic accurately.

Following these practices reduces misattribution, improves reporting accuracy, and allows you to make informed decisions based on real user behavior.

Final thoughts

Website traffic tracking is no longer straightforward. Tools like Perplexity Comet and ChatGPT Atlas introduce new paths to your content that GA4 does not always capture automatically. Without adjustments, your analytics may underreport or misclassify these sessions, creating blind spots in your data. Contact us for Integration of GA4 with Webflow.

By properly configuring GA4, creating custom channels, and using UTM parameters, you gain a clearer picture of where visitors come from and how they engage with your site. Accurate tracking enables smarter content strategies, better allocation of resources, and improved performance measurement. Understanding the nuances of AI-driven traffic ensures your decisions are based on reliable data, helping your website achieve stronger results over time.