YWT CookieKeeper Implementation

This document describes how to implement a server-side user identifier cookie (ywt_user_id) that ensures consistent tracking across multiple domains.

The cookie is used to restore user sessions and connect cross-domain events to a single customer profile in the CDP.

🎯 Objective

Each visitor should receive a unique persistent ID shared across all company domains.
This ID is stored in a cookie named ywt_user_id.
When users navigate between domains, the cookie value is passed through the URL as a query parameter ?ywt_user_id=<value>.
The cookie ensures stable attribution and identity resolution even with ITP (Safari) or adblocker restrictions.

🌐 Example Domain Setup

Domain	Description
example.com	Main site
exampleapp.com	App environment
examplemedia.com	Campaign or content domain
examplepromo.com	Landing page domain

All these domains share the same user identifier via the ywt_user_id cookie.

⚙️ Functional Logic

The cookie is set server-side, before any client-side scripts or GTM containers are loaded.

A client-side helper script then ensures the ID is passed between related domains.

1️⃣ ID Generation & Retrieval Logic

Step	Action	Result
1	Check if the current URL contains ?ywt_user_id=	✅ If present, use this value
2	If present → Set the ywt_user_id cookie with this value	Persistent identification
3	If not in URL → Check if a cookie already exists	✅ Use existing value
4	If not → Generate a new unique identifier	Create and store in cookie
5	Add ?ywt_user_id=<value> to all outbound links to other company domains	Enables cross-domain continuity

🎯 Objective

🌐 Example Domain Setup

⚙️ Functional Logic

1️⃣ ID Generation & Retrieval Logic

🧱 Cookie Specification