Cookies are small files that websites store in your browser to remember things about your visit. Learn what cookies are on a website, how they work, and why 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. If you have ever wondered what are cookies on a website, they 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?
Understanding how cookies work helps you see why they are so common. 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. There are also what are called third party cookies, which are set by a different website than the one you are visiting. These are commonly used for advertising and cross-site tracking. Many browsers are now limiting or blocking third party cookies because of privacy concerns.
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. To learn more about privacy rules around cookies, read cookie consent and GDPR. Cookies are closely related to website sessions, which the next chapter covers, and to browser storage, which goes into the different ways browsers hold data beyond cookies.
Frequently asked questions
Can you block cookies on a website?
Visitors can block cookies through their browser settings, and many do. When cookies are blocked, some website features stop working properly. Login sessions may not persist, preferences may reset on every page, and analytics data becomes less accurate. As a website owner, you should make sure your site works reasonably well even when some visitors have cookies disabled.
Are cookies safe or can they harm your device?
Cookies are just small text files. They cannot run programs, install anything, or access your files. They are not a security threat by themselves. The concern around cookies is about privacy, not safety. Some cookies track your activity across multiple websites for advertising purposes. That is why browsers now give users more control over which cookies they accept.
What is the difference between first-party and third-party cookies?
First-party cookies are set by the website you are visiting. They help with things like keeping you logged in and remembering your settings. Third-party cookies are set by a different website, usually for advertising or tracking across multiple sites. Browsers are increasingly blocking third-party cookies by default because of privacy concerns. Most website features you care about rely on first-party cookies, which are not affected by these changes.
Do cookies slow down your website?
Cookies themselves are tiny and have almost no impact on speed. But if your website sets a large number of cookies or sends them with every single request, it can add up. Keeping your cookies lean and only setting what you actually need keeps things efficient. WEMASY's website builder manages cookies sensibly out of the box, so your site does not get weighed down by unnecessary data.
How long do cookies stay on your browser?
That depends on how the cookie is set. Session cookies disappear as soon as you close your browser. Persistent cookies have an expiration date set by the website, which could be days, weeks, or even months. The website decides how long each cookie should last based on what it is used for. You can also manually clear cookies from your browser settings at any time. Learn more about how browser storage handles different types of data.
Are websites legally required to ask for cookie consent?
In many countries, yes. Privacy laws require websites to inform visitors about the cookies they use and get consent before setting non-essential ones. This is why you see cookie banners on most websites. The rules vary by region, but it is good practice to be transparent about cookies regardless of where your audience is. For a full breakdown, read cookie consent and GDPR.