What Is a Cookie?
On the internet, a cookie is a tiny text file that a website stores in your browser. It holds small bits of information so the site can remember you later.
Definition
A cookie is a small piece of data that a website sends to your browser. Your browser saves this data and sends it back to the website each time you visit or load a page from that site.
This data can include things like:
- A unique ID number for your browser
- Your language choice
- Items you added to a shopping cart
- If you are logged in or logged out
Why Cookies Matter
Cookies are important because they help websites:
- Remember you so you do not have to log in again every time
- Save settings like language or dark mode
- Keep carts and wish lists in online shops
- Measure visits so site owners know what pages people like
- Show ads that match your interests
They are also important for privacy. Because cookies can track how you use a site or even several sites, many countries have laws about how cookies must be used and explained.
How Cookies Work
Here is the simple flow of how a cookie works:
- You visit a website in your browser.
- The website sends a cookie with some data to your browser.
- Your browser stores that cookie on your device.
- Next time you open a page from that website, your browser sends the cookie back to the site.
- The site reads the cookie and uses the data to remember you or adjust what you see.
Cookies can have an expiration date. Some are deleted when you close your browser. These are called session cookies. Others stay on your device for days, months, or even years. These are called persistent cookies.
Cookie vs Related Terms
- Cookie vs Cache
A cookie stores small bits of user info like login status. A cache stores copies of web pages and images to make sites load faster. - First party cookie vs Third party cookie
A first party cookie is set by the website you are visiting. A third party cookie is set by another site, often an ad or tracking service. - Cookie vs Local Storage
Both save data in your browser. Cookies are sent to the server with each request. Local storage data usually stays in the browser and is not sent automatically.
Example of a Cookie
Imagine you visit an online store and log in. The website:
- Checks your username and password.
- Creates a cookie with a user ID that says you are logged in.
- Saves that cookie in your browser.
Later, when you come back, the store reads the cookie and says, This is the same user. It can show your name, your cart, and your order history without asking you to log in again.
FAQs
Are cookies safe?
Most cookies are safe because they are just text. They cannot run programs by themselves. The main risk is privacy, not direct damage to your device.
Can I turn off cookies?
Yes. You can block or delete cookies in your browser settings. But some websites may not work well if cookies are off. For example, you might not stay logged in or your cart may not be saved.
Why do websites show cookie banners?
Many laws require websites to tell users about cookies and sometimes ask for consent. The banner explains what cookies are used for and may let you accept or reject some of them.
What is a tracking cookie?
A tracking cookie follows your activity across pages or even across different websites. It is used to build a profile of your interests, often so advertisers can show targeted ads.
