Glossary

General

Term	Description
Property	A property is an entity the tracking engine is tracking. It is a website, app, or other digital property.
Hit	A hit is a single request to the tracking server. Hits are raw and yield no analytical value, after they're processed into events by the tracking pipeline, they can be used for analytics.
Event	An event is a single action that occurs on the property. Its relation to hit is 1-1. It is used to track the user's activity on the property.
User	A user is a person who visits the property. It is used to track the user's activity on the property.

Term	Description
Proto-session	A set of loosely connected Hits, that may in the future form one or more sessions. The hits are glued together by the identifiers (Client ID, SS).

Identifier type	GA4-compatible (measurement protocol)	Matomo-compatible (matomo.php)
Client ID - the ID assigned by the tracking engine to each device/browser combination, persisted in a cookie	`client_id`, `user_pseudo_id`	`_id`
User ID - the ID used in an internal user system, for example email, available after the login. The customer must manually set it as a tracking parameter, it's not automatically determined by the tracker	`user_id`	`uid`
Session stamp (SS) - hash calculated on the backend, from the incoming request elements - IP, User Agent, etc	none, calculated on the backend	none, calculated on the backend
Client-assigned session ID (CASI) - the session id as explicitly set by the client in the tracking request	`session_id`	none