# What is Cookies?

*Development · Last updated: October 12, 2026*

> HTTP Cookies

They are small data files stored in the browser by websites to remember user preferences and session status.

## Overview

Cookies are small pieces of text sent by a web server to your browser and sent back to the server on your subsequent visits. They prevent users from having to re-enter passwords on every page transition, preserve cart contents, and store site preferences. While first-party cookies are used for the site's own functions, third-party cookies are used to deliver targeted ads by tracking cross-site browsing habits.

***Analogy:** It is like the ticket number you are given when you leave your coat at a coat check; when you return, you show the ticket and the attendant knows which coat belongs to you even if they don't recognize you.*

## How it works

The web server adds a Set-Cookie command to the HTTP response header sent to the browser. The browser reads this command and stores the specified key and value pair on the local disk. When the user sends a new request to the same domain, the browser automatically sends this data back to the server under the Cookie header.

## Where it is used

They are used in user session management, cart tracking on e-commerce sites, and digital marketing analytics.

## Commonly confused with

They are confused with device fingerprinting; while cookies can be easily cleared from browser settings, fingerprints cannot be easily deleted because they rely on hardware features.

## Questions and answers

**Will clearing cookies harm my computer?**

No; only your open internet sessions will be closed and your theme or language preferences on sites will be reset.

**Why are third-party cookies being blocked?**

They are blocked by default by modern browsers because they violate your privacy by tracking your movements across different sites.

## Related terms

- [Session Intelligence](https://trescout.com/en/dictionary/session-intelligence/)
- [Fingerprint](https://trescout.com/en/dictionary/fingerprint/)
- [Digital Privacy](https://trescout.com/en/dictionary/digital-privacy/)
- [GDPR](https://trescout.com/en/dictionary/gdpr/)
- [Ad Tech](https://trescout.com/en/dictionary/ad-tech/)

This explanation was written in plain language for TreScout with AI and **machine-translated** from the Turkish original · the Turkish version prevails. If something looks wrong or missing, write to [hello@trescout.com](mailto:hello@trescout.com). [Read in Turkish →](https://trescout.com/dictionary/cookies/)

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Source: TreScout Dictionary · https://trescout.com/en/dictionary/cookies/