What are cookies? Why do websites use them?

Did you observe a small message popping up when you visit any website? Something that asks your permission to “accept cookies?” You being eager would have clicked okay to get access to the website. But have you ever sat back and thought what this is?

This notification is connected to how websites store information and maintain continuity while you browse. Cookies are not warnings or errors. They are the basic mechanism that helps websites function smoothly. If you are learning about websites, understanding cookies is an important step toward understanding how websites interact with browsers over time.

What are cookies?

Cookies are small pieces of text-based data that a website stores in a user’s browser. They are created by the website and saved locally on the user’s device. Cookies are not software programs, and they cannot run code. Their only purpose is to store and return information when the browser communicates with the website again.

In short, cookies help websites remember specific details about a visit, instead of treating every page load as a completely new interaction.

Why do websites use cookies?

Websites use cookies to maintain continuity between different actions and pages. Without cookies, a website would not be able to recognize that multiple requests are coming from the same user or browser.

It is by default that every page requested on the web is treated as a new and separate interaction. Cookies solve this limitation by allowing websites to attach a small memory to the browser, which can be referenced during future requests.

Here is a list of how websites use cookies:

• Keep track of ongoing interactions

• Maintain sessions across multiple pages

• Remember users’ choices and preferences

• Provide consistent behavior throughout a visit

If cookies were not a part of the website, many common website features would stop working or behave unpredictably. Navigation would feel disconnected, and user interactions would reset frequently.

How do cookies work on a website?

Cookies work through a simple exchange between the browser and the website. This exchange of data allows the website to recognize the browser and maintain continuity across interactions.

The process works as follows:

The browser sends a request to the website

When a user opens a website, the browser sends a request asking for page content. This request does not contain memory by default.

Website sends a cookie with its response

Along with the page content, the website can include a cookie that contains small pieces of information relevant to that visit.

Browser stores the cookie locally

The browser saves the cookie and associates it with the specific website that created it. Other websites cannot access this cookie.

Cookie is sent back on future requests

Every time the browser communicates with the same website again, it automatically includes the stored cookie with the request.

Website uses the cookie to maintain continuity

The website reads the cookie and uses it to recognize the browser, link requests together, and apply stored information. This process happens automatically in the background. The user does not need to manage cookies manually for normal browsing, and the browser enforces rules around how cookies are stored and shared.

What kind of information cookies store

Cookies are designed to store small and specific pieces of information that help websites function smoothly. They do not store large files or full user data. Instead, they store identifiers and settings that the website can use to retrieve or apply information correctly. The type of information stored in cookies depends on what the website needs to remember.

Common types of information stored in cookies include:

Session identifiers

These are unique values that help the website understand that multiple page requests belong to the same visit. They allow the website to connect actions across pages during a single browsing session.

Login and authentication status

Cookies indicate whether a user is logged in or logged out. They do not store passwords but act as a reference so the website knows the user has already been authenticated.

User preferences and settings

This includes information such as selected language, region, theme, or display preferences. Storing these details helps the website remain consistent across visits.

Interaction state information

Cookies can store whether a user has completed a step, seen a notification, or accepted a message. This prevents repetitive actions or repeated prompts.

Tracking and measurement identifiers

Some cookies store identifiers used for analytics. These help website owners understand general usage patterns without storing personal details directly.

If you are building a website, cookies are usually handled as part of your authentication flow, session management, and user settings. You will often define them while setting up logins, preferences, or integrations rather than during visual design. Most modern frameworks, CMS platforms, and hosting setups already provide default ways to manage cookies. Your role is to understand where cookies are being set, what they are used for, and how long they persist, so they align with how your website is supposed to behave.