GA4 Channel Grouping Explained: All 19 Default Channels

One of the main goals of Google Analytics is to identify the most effective channels, advertising campaigns, and content for attracting new customers or traffic. To decide how best to allocate resources or marketing budgets for a better return on investment, it’s important to understand the quality of traffic from each channel.

As I mentioned in my other article, “Google Analytics 4 (GA4): The Essential Guide”, you can assess traffic quality in the Acquisition Tab of Google Analytics 4.

Understanding traffic can be quite complicated, but the quickest and simplest way is to understand the Default Channel Grouping dimension. Today, I’ll guide you through the default channel groupings in Google Analytics. Before diving in, make sure you understand how UTM parameters work, because several of the channels below depend on them being set correctly.

The 19 Default Channels in GA4

GA4's default channel group now has 19 channels. This guide walks through each one, including the 2026-added AI Assistants channel that captures referrals from AI assistants like ChatGPT and Gemini.

1. Direct Traffic

Direct traffic refers to the visits that occur when people enter your website’s URL directly into their browser.

This includes visits from people who have bookmarked your webpage or added it to their favorites and later visit the page through these bookmarks or favorites. Additionally, if someone shares a link with you through instant messaging apps like WhatsApp or Facebook Messenger, and you click on that link to visit the website, it is also considered direct traffic.

Typically, direct traffic is an indicator of brand recognition or repeat customer visits. An increase in your direct traffic usually signifies a boost in your brand’s visibility or that you are gaining more returning customers.

2. Organic Search Traffic

Organic search traffic refers to the visits that occur when people click on natural (non-paid) search results on a search engine results page (SERP) and subsequently visit your website. This type of traffic originates from unpaid search results, which is distinct from the traffic generated through paid search ads.

For example, Terrence searches for the keyword “gdn” on Google, sees the search results, and then clicks on one of the natural search results, leading him to your website page.

3. Paid Search Traffic

Paid search traffic is generated from clicks on search ads, primarily from Google Search Ads or Bing Search Ads.

When people search on Google or other search engines and click on the paid search results marked as “Ads” on the search engine results page (SERP), those clicks contribute to paid search traffic.

However, there’s a situation to be aware of: if your Google Ads aren’t set up with Auto Tagging, your paid search traffic may be incorrectly categorised as organic traffic. Auto Tagging is a default setting in Google Ads, and typically, unless there’s an operational error, this issue should not arise.

For example, Terrence searches for “kickads” and clicks on the “Ad” for kickads.co displayed in the search engine results page.

4. Organic Social Traffic

Social traffic comes from social networks: the clicks that happen when people share links on platforms like Facebook, X (Twitter), Instagram and LinkedIn. In GA4, social traffic is split into two official channels: Organic Social and Paid Social. If you paste a link directly onto a social platform and someone clicks it, that click is categorised as Organic Social.

5. Paid Social Traffic

Paid Social is traffic from paid ads run on social platforms. To identify paid social accurately, tag your links with UTM parameters.

6. Display Traffic

If you run Google Display Network (GDN) ads, Auto Tagging (on by default) labels those clicks as Display traffic automatically. Running display ads on another network? Add UTM parameters to each link by hand so GA4 can attribute those visitors correctly.

7. Paid Video Traffic

YouTube ads work the same way: with Auto Tagging enabled (the default), GA4 files the resulting clicks under Paid Video. For video ads bought on other platforms, tag the destination links with UTMs yourself to see how much traffic each campaign really drives.

8. Paid Shopping Traffic

For Google Shopping ads, Auto Tagging (the default) sorts the clicks into Paid Shopping with no extra setup. Shopping ads on any non-Google platform need manual UTM tags, otherwise those visits are hard to track and attribute.

9. Cross-network Traffic

If you use Google’s Demand Gen and Performance Max ads, just select the Auto Tagging feature (which is the default setting), then the traffic generated from these ads will automatically be categorised as Cross Network Traffic.

10. Organic Video Traffic

Organic Video covers visitors who reach your site or app through non-ad links on video platforms such as YouTube, TikTok or Vimeo.

You rarely need to tag these links yourself, since Google can usually detect the source automatically.

11. Organic Shopping Traffic

Organic Shopping is traffic arriving from unpaid links on shopping platforms like Amazon or eBay.

As with organic video, manual UTM tagging is seldom necessary because Google generally recognises where the click came from.

12. Email Traffic

Email traffic refers to the visits generated from your email marketing campaigns.

It’s important to note that not all link clicks in emails are automatically counted as email traffic. To ensure that these clicks are correctly categorized under email traffic, you need to integrate your Email Direct Marketing (EDM) software with Google Analytics, or enable auto-tagging in your EDM tool, or manually add UTM parameters to your links, making sure the medium parameter is set to “email” (be aware of case sensitivity).

If you do not do this, Google Analytics 4 may count these link clicks (visiting your website) as direct traffic. This can affect the accuracy of your data and influence your decision-making, potentially leading you to believe that your email campaigns are ineffective and making incorrect conclusions based on that assumption.

13. Affiliate Traffic

If you’re not familiar with affiliate marketing, I recommend reading Affiliate Marketing 101: What it is and How to Get Started

In simple terms, affiliate marketing involves affiliate partners charging you based on the traffic they direct to your site. Many affiliate platforms track the performance of each affiliate website and allocate commissions based on the traffic they generate for you.

Generally, these affiliate platforms are more accurate in tracking the actual transaction amounts or values than Google Analytics. However, you can still track other metrics from these affiliates in Google Analytics, such as engagement and duration of engagement. To do this, you should create unique UTM parameters for each affiliate partner.

For a better understanding of how to create UTM parameters for affiliate traffic, I strongly recommend watching this video.

14. Referral Traffic

Referral traffic is the kind of traffic that comes from other websites.

This usually happens when other individuals or organisations write content about you, your products, or services on their own websites. When visitors from these websites click on links and visit your website, it generates referral traffic.

In Google Analytics, these external websites linking to your site are called referral domains, and the corresponding traffic is categorised as referral traffic. This type of traffic is an important indicator of how well-known and influential your website is outside of your own domain.

15. AI Assistants

Added by GA4 in 2026, this channel captures referrals from AI assistants: traffic where someone clicks through to your site from ChatGPT, Gemini, DeepSeek, Copilot or Grok (the rule matches medium ai-assistant or a known AI-assistant source). Note it excludes Google's own AI Overviews and AI Mode. As more people search via AI assistants, this is the key channel for seeing how much real traffic AI search actually sends you.

16. Audio

Traffic from ads on audio platforms such as podcasts (medium exactly matches audio).

17. SMS

Traffic from text-message links (source or medium exactly matches sms).

18. Mobile Push Notifications

Traffic from links in mobile push notifications (medium ends with push, or contains mobile/notification).

19. Paid Other

Paid advertising traffic that doesn't fit the search, social, video or shopping paid categories.

Unassigned

Unassigned is not one of the 19 official channels — it's GA4's bucket for traffic that matches none of the default channel rules. Custom UTM parameters that don't follow Google's guidelines end up here, which is why following Google's UTM guidelines matters for clean categorisation.

Through this article, we have gained a comprehensive understanding of various traffic sources in Google Analytics and how to track them. From direct traffic to social and affiliate traffic, analysing this data correctly helps optimise marketing strategies and improve return on investment. Mastering this knowledge is crucial for gaining deep insights into customer behaviour and enhancing website performance.

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FAQ

What is channel grouping in GA4? Channel grouping is how Google Analytics 4 categorises your traffic sources into predefined channels such as Direct, Organic Search, Paid Search, Display and Email, so you can compare the quality and performance of each channel in the Acquisition reports.

Why is my paid search traffic showing up as organic search? If Auto Tagging is not enabled in Google Ads, paid search clicks can be wrongly classified as organic traffic. Auto Tagging is Google's default setting, so this normally only happens through manual error.

What is Cross-network traffic in GA4? Traffic generated by Google's Demand Gen and Performance Max campaigns. With Auto Tagging enabled (the default), GA4 categorises these clicks automatically as Cross Network.

Why do my email clicks show up as direct traffic? Email clicks only count as Email traffic when your EDM software is integrated with Google Analytics, or your links carry UTM parameters with the medium set to "email" (case sensitive). Otherwise GA records those visits as direct traffic.

What is Unassigned traffic in GA4? Traffic whose custom parameters, such as UTM tags, do not follow Google's guidelines, so GA4 cannot fit it into any of the predefined channel groups.