Documentation
GA4 Channels report
Sessions, users, engagement and key events for each GA4 session default channel group, from Organic Search to AI Assistant, with each one's share.
The Channels report groups the site's GA4 sessions by GA4's session default channel group: Organic Search, Direct, Referral, Organic Social, Email, Paid Search, AI Assistant and the rest. Use it to see how much of the site's traffic search brings, how that share moved against the comparison period, and which channel's visitors engage and convert best.
How GA4 assigns a channel
GA4 places each session in a channel using Google's published rules, which look mainly at the session's source and medium (Default channel group). AutoPSEO reads the session-scoped version, sessionDefaultChannelGroup, which credits the channel that started each session. A returning visitor who first arrived from a newsletter and comes back today from a Google result is counted under Organic Search for today's session.
A few of Google's rules matter for SEO work:
- Organic Search covers every search engine on Google's list, not only Google, and it includes visits from Google's AI Overviews and AI Mode.
- AI Assistant holds visits from assistants such as ChatGPT, Gemini, DeepSeek, Copilot or Grok. GA4 gives these sessions the medium
ai-assistant. - Direct is a session whose source is
(direct)with no medium. - Unassigned is what GA4 uses when none of its channel rules matched the session.
What the report shows
- Five cards for the whole segment: Sessions, Active Users, Page Views, Engagement Rate and Key Events, each with its change.
- A bar chart of the ten channels with the most sessions, labelled with each channel's share of the total.
- A table with Channel, Sessions, Active Users, Engagement, Key Events and % of Sessions, sorted by sessions, 50 rows to a page.
The All, Winning and Losing tabs split the channels by whether their sessions rose or fell against the comparison period. With comparison disabled, every channel that had sessions counts as winning, so set a comparison before you rely on the tabs.
Questions to ask it
- Is search still growing? Compare with the previous year and check Organic Search's sessions and its % of Sessions. If it lost sessions, the GSC Dashboard tells you whether clicks fell too, which separates a ranking problem from a tracking one.
- Which channel brings the best visitors? Read Engagement and Key Events across rows. Organic Search sessions that engage but rarely convert often mean the pages answer the search without offering a next step.
- How fast is AI traffic moving? Watch the AI Assistant row over a few months. LLM Traffic splits it by assistant, and because it also recognises assistants by their source, it can count visits GA4 filed under Referral.
Channels or sources?
A channel is a bucket of sources. When you need to separate Google from Bing inside Organic Search, or see which site is behind a jump in Referral, open Sources, which lists every source / medium pair.
The segment set in GA4 filters applies here as everywhere else, so with a custom source / medium list the report only shows the channels those sources belong to.