What Are HTTP Cookies And How Do They Work?

Have you ever wondered how some websites remember your preferences, such as your username, password, language, or theme? Or how online shopping carts keep track of the items you add to them? Or how websites show you personalized ads based on your browsing history? The answer is HTTP cookies.

HTTP Cookies are small pieces of data that are sent from a web server to your browser and stored on your device.

They are used to store stateful information, such as your identity, preferences, or behavior, and send it back to the server with every request. This way, the server can recognize you and provide you with customized content or functionality.

In this comprehensive blog post, we will explain what HTTP cookies are, how they are created, sent, and stored, and what benefits and risks they pose for web users.

What Are HTTP Cookies?

HTTP Cookies (also called web cookies, browser cookies, or simply cookies) are small blocks of data created by a web server while a user is browsing a website and placed on the user’s device by the user’s web browser.

The name cookie comes from the term magic cookie, which is a packet of data that a program receives and sends back unchanged. The term was coined by web browser programmer Lou Montulli in 1994.

HTTP cookies are mainly used for three purposes:

Session management: Cookies can store information such as your login status, shopping cart items, game scores, or anything else that the server should remember across multiple pages or visits.

Personalization: Cookies can store your preferences, such as your preferred language, theme, or settings, and apply them to the website.

Tracking: Cookies can record and analyze your browsing activity, such as which pages you visited, how long you stayed, what you searched for, or what ads you clicked on.

How Are HTTP Cookies Created, Sent, And Stored?

HTTP cookies are created by the web server using the Set-Cookie header in the HTTP response. The header contains the name and value of the cookie, as well as some optional attributes that specify when and where the cookie should be sent or deleted.

For example:

Set-Cookie: user_id=1234; Expires=Fri, 15 Sep 2023 15:45:48 GMT; Domain=example.com; Path=/; Secure; HttpOnly

This header instructs the browser to store a cookie named user_id with a value of 1234 on the device. The cookie will expire on September 15th, 2023 at 15:45:48 GMT. The cookie will only be sent to the server if the request is for example.com or any of its subdomains.

The cookie will only be sent over HTTPS connections. The cookie will not be accessible by JavaScript code.

The browser usually stores the cookie in a text file or a database on the device. Different browsers may have different ways of storing and managing cookies. You can view and delete the cookies stored by your browser using its settings or tools.

The browser sends all the stored cookies that match the request back to the server using the Cookie header in the HTTP request.

For example:

Cookie: user_id=1234; session_id=abcd

This header tells the server that the request is from a user with an ID of 1234 and a session ID of abcd. The server can use this information to provide personalized content or functionality to the user.

What Are The Benefits And Risks Of HTTP Cookies?

HTTP cookies have both benefits and risks for web users. Here are some of them:

Benefits of HTTP cookies

Cookies enable web servers to provide stateful and personalized services to users. Without cookies, users would have to log in every time they visit a website or enter their preferences every time they change a page.

Cookies can enhance the user experience by remembering their choices, preferences, and interests.

Cookies can help web developers and marketers to analyze user behavior and improve their websites and products.

Risks of HTTP cookies

Cookies can pose privacy and security risks for users. Cookies can store sensitive information such as passwords, credit card numbers, or personal details that can be stolen or misused by hackers or malicious websites.

Cookies can also be used to track users across different websites and collect their browsing history without their consent or knowledge. This can result in unwanted ads, spam, or identity theft.

Cookies can also affect the performance of websites and devices. Cookies are sent with every request, which can increase the network traffic and slow down the loading time. Cookies also take up space on the device’s memory, which can reduce its efficiency.

How Can You Manage HTTP Cookies?

As a web user, you have the right and the responsibility to manage the cookies that are stored on your device. You can do this by using the settings or tools provided by your browser or by using third-party software or extensions.

Some of the actions you can take to manage cookies are:

Accept or reject cookies from specific websites or domains. You can also choose to accept only first-party cookies (from the website you are visiting) or reject third-party cookies (from other websites that are linked to the website you are visiting).

Delete cookies from your device manually or automatically. You can also choose to delete cookies when you close your browser or after a certain period of time.

View and edit the cookies stored on your device. You can also see the details of each cookie, such as its name, value, expiration date, domain, and path.

Block or allow cookies based on their type or purpose. You can also opt out of cookies that are used for tracking or advertising purposes.

You should be aware that managing cookies may affect the functionality and performance of some websites. Some websites may not work properly or at all if you block or delete their cookies.

Some websites may also ask for your consent before storing cookies on your device. You should read their privacy policies and terms of use before accepting or rejecting their cookies.

Conclusion

HTTP Cookies are small pieces of data that are sent from a web server to a browser and stored on a device. They are used to store stateful information, such as your identity, preferences, or behavior, and send it back to the server with every request.

Cookies enable web servers to provide stateful and personalized services to users, but they also pose privacy and security risks for users. You can manage the cookies that are stored on your device by using the settings or tools provided by your browser or by using third-party software or extensions.

We hope this blog post has helped you understand what HTTP cookies are and how they work.