Privacy
Cookieless tracking
Also called cookie-free measurement.
Cookieless tracking is measurement that does not write cookies or other durable storage on the visitor's device. Tarsier works this way.
How it is measured
The script sends each page event to the collector without leaving a stored ID in the browser. Check it in DevTools: the Application panel should show no cookies, no localStorage keys, and no IndexedDB entries from the tracker.
Without a stored ID, you cannot link a person across days. Counts of pageviews and sessions hold up. Returning-visitor counts do not, and the tool should not pretend they do.
Worked example
A neighborhood bakery site gets 2,300 pageviews in a week. In the browser, the storage panel is empty after five visits. The dashboard shows pageviews, top pages, and referrers, but no "returning visitor" line.
The owner compares to an older cookie-based tool that reported 1,150 unique visitors. The new tool reports a lower and differently defined number, and the owner stops comparing them head to head.
How it differs
Cookieless tracking avoids device storage. Fingerprinting avoids cookies too but builds a signature from browser traits. Cookieless excludes any lasting key on the device; fingerprinting excludes none and can follow people more tightly.
Common errors
Assuming cookieless means no personal data is processed, when IP addresses may still be handled. Calling fingerprinting cookieless and believing it needs no consent. Comparing unique visitors to a cookie tool. Forgetting that tag managers can add cookies. Claiming no consent is needed anywhere without legal advice.
In practice
Open DevTools on your own site and check cookies and storage after loading a few pages. Write down what you see. If other scripts set cookies, those are the ones to review.