When measuring activity with the tracking API for Piwik PRO, you can use the following HTTP headers:
- Host: The hostname of the HTTP request, the hostname of the Piwik PRO server
- Referrer: Used to track referrer information like website, search engine or social network.
- User-Agent: Used to detect the information about browsers, operating system, devices by the device-detector library.
- Cookie: Used for opted-out from tracking, or when the third0party cookies are used.
- Origin: Used when the cross-origin resource sharing is enabled.
- Accept-Language: Used to detect the user language.
- X-Forwarded-Proto, X-Forwarded-Host, X-Forwarded-For: Used when Piwik PRO is set up behind a proxy.
- DNT: Used to detect whether a visitor device is opted-out from tracking.