How does a cookie differ from localStorage in analytics tools?

A cookie is sent automatically with every request to the same domain and carries an expiry date, so the server can read it too. A value in localStorage travels nowhere until page code reads it and has no automatic expiry, but it disappears in private browsing or when site data is cleared.

Does an analytics script require a cookie consent banner?

It depends on the law that applies in the market and on what is stored. A first-party cookie and the absence of third-party advertising cookies reduce the surface but do not automatically remove the duty to inform visitors; the final call is a legal one and has to be checked against local law.

Cookie

Beginner

Updated Jul 11, 2026 Shahin editorial 2 min read

PronunciationEN/ˈkʊki/

A cookie is a small piece of data that a site stores in the browser, and the browser sends it back on later requests to the same domain.

A cookie is written either by the server through the Set-Cookie header or by JavaScript in the browser, and attributes such as Domain, Path, Expires, SameSite and Secure govern its scope and lifetime. The decisive split is first-party versus third-party: a first-party cookie belongs to the domain the visitor is already on and is what identifies a returning visitor, while a third-party cookie is written by another domain and is now widely blocked by browsers. The common error is to treat a cookie as a person; policies such as Intelligent Tracking Prevention in Safari cut the lifetime of a script-written cookie to a few days, so the same person is counted as a new visitor when they come back.

FAQ

Sources:MDN — Using HTTP cookies