Cookie Keeper — extending cookie lifetime

Why you need Cookie Keeper

Modern browsers significantly limit cookie lifetime:

• Safari (ITP) — JavaScript cookies max 7 days, 3rd-party blocked
• Firefox (ETP) — a 7-day limit for known trackers
• Chrome — a planned 3rd-party cookie restriction

This means a user who returns after a week is treated as new — and you lose data.

How Cookie Keeper works

1. Your sGTM container runs on your own domain (e.g. track.yourdomain.cz)
2. Cookies set server-side via the Set-Cookie header are treated by the browser as 1st-party
3. The browser gives them a significantly longer lifetime (up to 2 years)
4. Cookie Keeper automatically refreshes and synchronizes the identifiers

Benefits

• More accurate conversion attribution (the user is recognized even after weeks)
• Less user duplication in GA4
• Better data for remarketing
• A higher return on ad investment

Requirements

• The PRO plan or higher — Cookie Keeper is a premium feature
• Your own tracking domain (a verified CNAME)
• A correctly configured sGTM container

Setup

Cookie Keeper activates automatically once all requirements are met. No further configuration is needed — you just need your own domain and a PRO+ plan.