Technology
How does a browser cookie work?
A browser cookie works as a small text file a website stores on your device to remember information between visits. It lets sites keep you logged in, save your preferences, and track items in a cart — by sending the saved data back each time you return.
See it in motion.
Watch a 2-minute animated lesson that shows exactly how a browser cookie works.
Step by step
- 1A website saves a small text file in your browser.
- 2Your browser sends it back to that site on each visit.
- 3It remembers logins, settings, and shopping carts.
- 4'Third-party' cookies can track you across different sites.
- 5You can view, block, or delete cookies in your browser.
Frequently asked questions
- What does a browser cookie do?
- It stores small bits of data so a website can remember you — keeping you logged in, saving preferences, or holding your cart between visits.
- Are cookies dangerous?
- Most are harmless and useful, but third-party tracking cookies can follow your activity across sites, a privacy concern you can block.
- What's the difference between first- and third-party cookies?
- First-party cookies are set by the site you're on; third-party ones come from other domains (often advertisers) and can track you across sites.