# Using the Referring URL Parameter

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The Referring URL is the [HTTP Referrer](https://en.wikipedia.org/wiki/HTTP_referer) value that impact.com records from the user's browser at the time of a click and is a good indicator of where traffic to your website is coming from. However, it is not 100% trustworthy or reliable as a tracking source, as it is highly dependent on how the click was made or the link was opened. There is a myriad of factors that can affect what gets sent to impact.com as the Referring URL.

#### Factors that affect Referring URL reliability

If you see clicks in the [*Performance by Referring Domain*](https://app.impact.com/secure/advertiser/engage/additionalreports/report/viewReport.report?id=5243) report with a “No referring domain" status in the *Domain* column, it often means that there is no Referring URL information available due to any of the following reasons:

* The user manually entered the site URL into the browser address bar.
* The user visited the site via a browser-maintained bookmark.
* The user opened the site as the first page in a new window or tab, such as by right-clicking a link.
* The user clicked a link in an external application.
* The user switched from a secure protocol (https) to a non-secure protocol (http).
* The user switched from a secure URL (https) to a completely different secure URL (https).
* The user may have security software installed (antivirus, firewall, etc.) which strips the referrer from all requests.
* The user is behind a proxy server that strips the referrer from all requests.
* The user visited the site programmatically without setting the referrer header (the use of searchbots).
* Some browsers’ privacy policies limit access to prevent `HTTP_REFERER` from being passed.
* The user has a browser add-on or extension that blocks it for privacy reasons.

{% hint style="info" %}
**Note:** impact.com recommends that you do not use the Referring URL option in payout groups when determining payouts to partners, and not to lean too heavily on the Referring URL as a source of data for decision making.
{% endhint %}

<div data-with-frame="true"><figure><img src="https://4048883401-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FwMLlMoFBtKJa8ptd3zaw%2Fuploads%2Fgit-blob-b3dac2d26258607a950b9584512ad5f86c1a701c%2F9e9ded014561edb602f4d45bb1a5ca1af1cffee80fc2c75e4ba595b98c4da955.png?alt=media" alt=""><figcaption></figcaption></figure></div>


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