Code such as a GTM web container or gtag.js sends events and parameters from a page. Some implementations need no separate server infrastructure, but accurate action definitions and tag validation are still required.
Browser restrictions, blocking tools, denied consent, and implementation errors can prevent observation. Do not assume a fixed loss percentage for every site; compare request logs, debugging tools, and verifiable business records under comparable conditions.
Server-side tagging moves some processing and delivery to a server you manage. It does not restore every browser signal or bypass a user’s consent choices. Evaluate costs, operating capacity, data requirements, and actual measurement problems before adopting it.