When measuring activity with the Matomo (Piwik) Tracking API, the following HTTP headers may be used:

  • Host – the hostname of the HTTP request, the hostname of the Matomo server.
  • Referer – used to track Referrer information such as website, search engine, social network.
  • User-Agent – used to detect the information about browsers, operating system, devices by device-detector library.
  • Cookie – when Opted-out from tracking, or when Third party cookies are used.
  • Origin – used when cross-origin resource sharing is enabled.
  • Accept-Language – used to detect the users’ language
  • X-Forwarded-Proto, X-Forwarded-Host, X-Forwarded-For – when Matomo is setup behind a proxy
  • DNT – used to detect whether a visitor’s device is opted-out from tracking (Matomo privacy)
Previous FAQ: How do I fix the tracking failure “The site does not exist.”