Find out where visitors come from and target those sources with optimizations.
Traffic source attributes help you understand how visitors arrive at your site. You can use this data to gain insights into where visitors come from and how those sources convert. You can also use these attributes to build audiences for variation targeting and to apply filters to optimization results.
How traffic source is determined
Each traffic source represents the last known touchpoint that led a visitor to your site. That information is captured when the visitor first arrives, based on the previous URL (the referrer) and the URL they landed on (the hosting page).
Once a traffic source is assigned, it's maintained for the duration of the session. If a visitor returns through a new channel later, the most recent traffic source is assigned.
Traffic source types
Optimize categorizes traffic sources based on where a visitor came from before landing on your site. This table outlines each traffic source type, how it’s detected, and any relevant fallback behavior.
Traffic source
Description
Generative AI
Triggered when — a visitor clicks a link from generative AI chat tools (e.g., ChatGPT, Claude, Copilot, Gemini, Perplexity, etc.)
Detected via – Generative AI referrers, or via generative AI URL parameters
Email
Triggered when — a visitor clicks a link in an email (e.g., newsletter or campaign)
Detected via — referrer includes terms like mail, webmail, or live
OR — referrer is empty and landing page includes utm_source=email
Direct navigation
Triggered when — a visitor types your site URL directly into their browser
Detected via — empty referrer and no email-related patterns
Fallback — also used when the source can't be determined due to browser or OS restrictions
Search paid
Triggered when — a visitor clicks a paid ad in search engine results
Detected via — search engine referrer with aclk, gclid, or paid UTM tags
Search organic
Triggered when — a visitor clicks a non-ad link in search results
Detected via — search engine referrer with no paid indicators
Social paid
Triggered when — a visitor clicks a paid ad on a social platform
Detected via — social referrer with paid-related UTM parameters
Social organic
Triggered when — a visitor clicks a non-ad link on a social network
Detected via — social referrer, with no paid, email, or search match
Other paid
Triggered when — a visitor clicks a paid ad not classified as search or social
Detected via — paid activity found, but doesn’t match another paid category
Recirculation
Triggered when — a visitor navigates between pages on your site
Detected via — referrer and landing page share your domain, with no stronger match
Other
Used when — traffic doesn’t match any other classification
Captures — ambiguous or uncategorized visits
How to use traffic source attributes
Audiences — Use traffic source attributes as conditions when defining who should see specific variations
Results filters — Apply traffic source filters when viewing your optimization results to compare performance by source