What is a session cookie?
A session cookie is a cookie with no expiry date, so your browser deletes it the moment you close it. It exists to remember things for the length of a single visit, and nothing longer.
Session vs persistent
There are two kinds of cookie by lifespan. A session cookie is temporary and vanishes when you close the browser. A persistent cookie has an expiry date and sticks around for days, months or longer, so the site can recognise you on your next visit. Analytics tools such as GA4 use persistent cookies so a returning visitor is not counted as brand new every time.
What session cookies are used for
- Keeping you logged in while you move between pages.
- Holding your shopping basket during a single visit.
- Carrying security tokens that protect a form submission.
Do session cookies need consent?
It depends on purpose, not lifespan. A strictly necessary session cookie (login, basket, security) is exempt from consent. A session cookie used for analytics or marketing still needs consent under PECR and GDPR, even though it only lasts for one visit.
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