Quick answer
The referrer is the URL of the page that led to the current request, sent by the browser in the HTTP Referer header (spelled with one r) and available to scripts as document.referrer. Analytics tools use it to tell where a visit came from.
What is the referrer?
When a visitor clicks a link, the browser tells the new page where they came from. It does this in the Referer header of the request (misspelled in the original HTTP specification and never fixed) and in document.referrer for scripts. Analytics tools read it to decide the visit's source and channel.
What browsers actually send
The Referrer-Policy decides how much is sent. Browsers default to strict-origin-when-cross-origin:
| Click from | To | Referrer sent |
|---|---|---|
| https://blog.example.com/post?id=7 | https://blog.example.com/pricing (same site) | Full URL |
| https://news.example.org/article/123 | https://shop.example.com/ (other site) | https://news.example.org/ only |
| https://secure.example.org/ | http://old.example.com/ (HTTPS → HTTP) | Nothing |
So for traffic from other sites you normally see the domain, not the page. A site can choose a stricter policy (no-referrer) or a looser one for its own links.
Why referrers go missing
- Apps and email. Messaging apps, mail clients and PDFs often open links without a referrer (dark social).
- Policies. The linking site sets
no-referreror links withrel="noreferrer". - Downgrades from HTTPS to HTTP.
- Redirects through services that strip it.
- Typed URLs and bookmarks, which genuinely have no referrer.
These visits land in direct, which is why direct traffic is never only people typing your address. Adding UTM parameters to links you control keeps the source even when the referrer is lost.
From referrer to channel in TapCub
Web analytics › Sources has a Referrers tab next to channels, search engines, AI sources and UTM. Channels combine UTM tags, click IDs and the referrer; organic search terms appear only when the referrer actually carried them, so that column is often thin. See how channels are decided and referral traffic.
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Product Experience Specialist
Explores usability, user journeys, and feature adoption through practical examples of onboarding and everyday product use.