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Ever visited a website, closed your browser, then returned later to find it still remembered your login details or shopping cart? That’s the magic of browser cookies at work. But what exactly are cookies, and how did they become a fundamental part of the web?

In this article, we'll break down what browser cookies are, their history, how they function, and why they matter for both users and developers. Whether you’re a curious internet user or a frontend developer looking to manage cookies effectively, this guide will give you a solid understanding.

At their core, browser cookies are small text files stored on a user's device by a website. They contain data that helps websites remember information between visits.

Essentially, cookies allow each site to recognise users as the same person that has visited the site before.

Why Do Websites Use Cookies?

At their core cookies do have a legit purpose that can be leveraged to enhance user experience with some examples being:

Session Management - Keeping users logged in or maintaining shopping carts.

Personalisation - Remembering user preferences like dark mode or language settings.

Analytics - Helping websites understand user behaviour to improve services.

Cookies, like actual cookies, can be both good and bad it all depends on how you use them.

First-party cookies used by the site you’re visiting are mostly harmless, while third-party cookies are used for tracking across sites are facing major privacy crackdowns

The Good	The Not So Good
They keep you logged in, remember your preferences.	Third-party cookies track users across sites, often without clear consent.
Websites can tailor content to your interests, making browsing more enjoyable.	Poorly managed cookies can be exploited for session hijacking or data leaks.
Site owners can track user behaviour to improve the user experience.	Ever searched for a product and then seen ads for it everywhere? That’s cookies at work.

A magic cookie is the ancestor of the modern browser cookie. A small piece of data exchanged between a server and a client to maintain session state or provide authentication.

They were originally used in Unix systems to track logged-in users and enable secure communication.

Unlike modern browser cookies, magic cookies weren’t initially designed for the web, but their core idea inspired HTTP cookies, which became essential for internet functionality.

Magic cookies still play a role in secure authentication and server communications, particularly in session management and token-based security models. While HTTP cookies have evolved separately, the concept of using small data tokens to maintain a session is still widely used in modern computing.

Feature	Magic Cookies	HTTP Cookies
Origin	Unix systems	Web browsers
Purpose	Authentication, session tracking	Storing user data for personalization & tracking
Encrypted?	Yes	Sometimes (depends on implementation)
Who Can Read It?	The server that created it	Depends on settings (some are accessible via JavaScript)
Example Use Case	Logging into a Unix server	Remembering login details on a website

For developers, managing cookies is crucial for authentication, personalisation, and tracking. Here’s a basic example using JavaScript:

Setting a Cookie

This creates a cookie named username that expires at the end of 2025.

Getting a Cookie

This retrieves all cookies for the current website.

Deleting a Cookie

Setting an expiration date in the past removes the cookie.

Not all cookies are created equal. Let’s break them down into different categories.

Magic Cookies

Unlike modern browser cookies, magic cookies weren’t initially designed for the web, but their core idea inspired HTTP cookies, which became essential for internet functionality.

A magic cookie is a small piece of data exchanged between a server and a client to maintain session state or provide authentication. They were originally used in Unix systems to track logged-in users and enable secure communication.

First-Party Cookies

A first party cookie exists on the same domain website you're visiting directly. They are generally considered to be safe and reliable, matching the reputation and credibility of the website involved.

Third-Party Cookies

A third-party cookie is a cookie that belongs to a domain other than the one displayed in the browser. In contrast with first-party cookies, which are associated with the same domain that appears in the user's browser.

Session Cookies

These are stored temporarily and deleted when the user closes the browser for example a shopping cart that resets after closing the tab.

Persistent Cookies

These type of cookies persist on the user's device for a set period, even after closing the browser. Examples where persistent cookies are used are websites that remember your login credentials for a week.

Performance Cookies

As the name suggests, performance cookies are used to measure performance. Performance cookies don’t track personal information or follow you across multiple websites. Instead, they help website owners optimise speed, layout, and usability.

Secure & HttpOnly Cookies

Secure Cookies are only sent over HTTPS for security whilst HttpOnly. Cookies are not accessible via JavaScript, reducing security risks.

Now, let’s rewind a bit and look at how cookies came to be.

The story of cookies begins in the early days of the internet when the web was far less interactive than it is today.

1994: The Birth of Cookies

Lou Montulli, a Netscape engineer, invented cookies in 1994. At the time, websites couldn't remember anything about users between page visits. Netscape was working on an early online shopping system and needed a way to store shopping cart data without using server storage.

Montulli’s solution was simple yet powerful: store small pieces of information directly on the user’s computer and send them back with future requests. This allowed the website to “remember” things about a user without bloating server databases.

1995 - 2000: The Rise and Controversy of Cookies

As cookies became widespread, businesses saw their potential for tracking users across websites. Companies could monitor browsing habits, which raised privacy concerns.

In 1996, The Financial Times published the first major article warning about the privacy implications of cookies, and by 2000, the U.S. Federal Trade Commission (FTC) started investigating online tracking.

2000 - Present: Regulation and Evolution

In the last 20 years, there are have been some major changes to the nature of cookies. Governments have introduced laws to regulate cookie usage, forcing browser vendors to take increasingly more radical steps to protect users privacy concerns.

2000

The Financial Times published the first major article warning about the privacy implications of cookies, and by 2000

2002

The EU's ePrivacy Directive required websites to inform users about cookies.

2011

The "EU Cookie Law" made it mandatory for websites to ask for consent before storing cookies.

2015

Apple made a bold move by allowing ad blockers in Safari, giving users an easy way to prevent ads and the hidden tracking cookies they carried from ever reaching their devices.

2017

Apple’s Intelligent Tracking Prevention (ITP) 2.0 blocked third-party cookies entirely. Ads were still displayed, but advertisers could no longer track users across sites, making revenue attribution and targeted advertising much harder.

2018

The General Data Protection Regulation (GDPR) introduced stricter rules on tracking and user consent.

2019

Mozilla Firefox introduced controls to disable third-party cookies, further limiting tracking across multiple websites.

Apple’s ITP 2.2 even restricted first-party cookies, allowing them to last only 24 hours making it difficult for businesses to analyse long-term user behaviour.

As the browser most dependent on ad revenue, Google Chrome was the last to act. Instead of banning cookies outright, Google proposed the Privacy Sandbox, a set of tools to replace third-party cookies with more privacy-friendly tracking methods.

2020

Google announced plans to phase out third-party cookies in Chrome, aiming for a more privacy-focused web.

Apple became the first major browser to implement automatic third-party cookie blocking, effectively making traditional cross-site tracking impossible for Safari users.

2021

Google planned to phase out third-party cookies by 2023 but faced pushback from advertisers, causing delays.

Mozilla introduced Total Cookie Protection, a feature that isolated cookies per site, preventing advertisers from tracking users across the web.

2022

After widespread criticism of Google’s first attempt at a cookie replacement FLoC, the company pivoted to Topics API, which groups users into broad interest categories rather than tracking their individual behaviour.

Back in the late 1990s, the Internet Engineering Task Force saw the potential privacy risks of third-party cookies and proposed a recommendation (RFC 2109) to block them. However, their plea was ignored by the most popular browsers at the time Netscape Navigator and Internet Explorer.

At the time, the web was still evolving, and the importance of advertising revenue was growing. Automatically blocking third-party cookies would have

Even though RFC 2109 suggested blocking third-party cookies by default, there was no way to enforce this recommendation.

Browser vendors prioritised convenience and business interests over privacy, so they left third-party cookies enabled by default, setting the stage for decades of online tracking.

For years, third-party cookies became the backbone of online advertising, leading to the rise of behavioural tracking and personalised ads.

Where Did All The Cookies Go? What This Means for Developers.

Browser cookies have been a staple of the internet for decades, but their future is uncertain. With growing concerns over privacy, security, and user tracking, major browsers like Chrome, Safari, and Firefox are taking steps to phase out third-party cookies.

With third-party cookies effectively becoming obsolete, developers must rely on first-party data. This means adapting to new methods, focusing on privacy-first solutions.

As the cookie crumbles, there are new alternative technologies are emerging to fill the gap:

Privacy Sandbox (Google’s Alternative)

A set of APIs that aim to provide targeted advertising without tracking individual users.

First-Party Data

Companies will rely more on data collected directly from users rather than third-party trackers.

Local Storage & Session Storage

Used for saving user preferences without sending data to a server.

Server-Side Tracking

Websites shifting to backend tracking methods that don’t rely on cookies.

Browser cookies have come a long way since their invention in 1994. Initially designed for simple session management, they quickly became a tool for tracking, personalisation, and analytics which has rightfully lead to privacy concerns and regulatory changes.

As we move toward a cookie-less future, understanding cookies remains essential for both developers and users. Whether you're managing user authentication, optimising website performance, or ensuring compliance with privacy laws, cookies continue to play a key role in the web ecosystem.