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