What Are Cookies?

Cookies are small text files that web servers send to a user’s web browser, which stores them on the client’s device. These files contain data that help websites remember information about users, such as login status, preferences, or tracking identifiers.

Cookies were introduced in the early 1990s to address the challenge posed by the HTTP protocol’s statelessness — meaning that each request to a server is independent and does not inherently carry information about previous interactions. Cookies allow websites to “remember” users and their interactions across sessions.

Each cookie consists of key-value pairs and a set of metadata that define the cookie’s scope, lifespan, and security properties. The browser automatically includes relevant cookies in subsequent HTTP requests to the appropriate domains, enabling servers to maintain a continuous user experience.

Major Use Cases of Cookies

Cookies are vital across many web application domains due to their ability to persist state and track information. Below are key use cases:

1. Session Management

Cookies enable websites to identify returning users and maintain session continuity without requiring users to authenticate on every page load. For example, after logging in, a session cookie keeps a user logged in until they log out or the session expires.

2. User Preferences and Personalization

Cookies store user settings such as language preferences, theme choices, or layout configurations. When a user revisits, the site can retrieve these preferences and tailor the interface accordingly.

3. Shopping Cart Persistence

E-commerce websites leverage cookies to remember products added to a user’s cart even if the browser is closed and reopened before checkout, enhancing the shopping experience.

4. Tracking and Analytics

Cookies collect data on user behavior, page visits, and navigation paths. Analytics platforms use cookies to generate insights about website performance and user engagement. Advertising networks use third-party cookies to track users across sites for targeted ads.

5. Security

Cookies help secure web applications by storing tokens or flags used in authentication workflows, CSRF protection, and managing user permissions.

6. Legal Compliance

Cookies assist in storing consent information, ensuring compliance with data protection regulations like the General Data Protection Regulation (GDPR) and California Consumer Privacy Act (CCPA).

How Cookies Work Along with Architecture

Cookies operate at the intersection of HTTP protocol, client (browser) storage, and server-side application logic. The architecture supporting cookie functionality includes several components:

1. HTTP Headers and Communication

• When a client sends a request to a server, it includes a Cookie header containing cookies relevant to the request URL’s domain and path.
• The server can send back one or more Set-Cookie headers in its response to instruct the browser to store new cookies or update existing ones.

Example HTTP response header:

Set-Cookie: sessionId=abc123; Expires=Wed, 09 Jun 2026 10:18:14 GMT; Path=/; Secure; HttpOnly; SameSite=Strict

2. Browser Cookie Storage

• Browsers maintain a “cookie jar” storing cookies by domain and path.
• They enforce scoping rules, ensuring cookies are only sent to appropriate URLs.
• Cookies are stored on disk or in memory depending on persistence.

3. Cookie Attributes and Their Impact

• Domain: Restricts the domains to which the cookie will be sent. Cookies set for example.com are sent to sub.example.com but not to otherdomain.com.
• Path: Restricts the URL paths on the domain for which the cookie is valid.
• Expires/Max-Age: Defines when a cookie will be deleted. Session cookies expire when the browser closes; persistent cookies survive beyond sessions.
• Secure: Ensures cookies are only sent over HTTPS connections.
• HttpOnly: Prevents client-side JavaScript from accessing cookies, mitigating some XSS attacks.
• SameSite: Controls cross-site cookie sharing to prevent CSRF and privacy leaks. Values include Strict, Lax, or None.

4. Server-Side Handling

• Servers read cookies from incoming requests and use their data to maintain sessions, authenticate users, or track state.
• Servers can update or delete cookies by sending updated Set-Cookie headers.

5. Third-Party Cookies

• These are cookies set by domains other than the one shown in the browser’s address bar, typically used by advertisers or analytics services.
• Modern browsers are increasingly restricting third-party cookies due to privacy concerns.

Detailed Workflow of Cookies

1. Initial Visit

• User visits a website; the browser sends a request without cookies.

2. Server Response with Cookies

• Server responds with Set-Cookie headers to establish sessions or preferences.

3. Browser Stores Cookies

• The browser saves cookies respecting domain, path, security attributes.

4. Subsequent Requests

• Browser automatically includes relevant cookies in HTTP requests for that domain/path.

5. Server Processes Cookies

• Server uses cookies to authenticate the user, retrieve session data, or customize the response.

6. Cookie Updates

• Server can update cookies by sending new Set-Cookie headers with modified values or expiration.

7. Cookie Expiration or Deletion

• Cookies expire naturally after their expiry time or are deleted by explicit instructions or user actions.

Step-by-Step Getting Started Guide for Cookies

Step 1: Understand Cookie Fundamentals

Familiarize yourself with cookie components — name, value, domain, path, expiry, and security flags.

Step 2: Setting Cookies from the Server

Example: Node.js Express

res.cookie('userId', '12345', {
  maxAge: 24 * 60 * 60 * 1000, // 1 day
  httpOnly: true,
  secure: true,
  sameSite: 'Strict',
  path: '/'
});

Step 3: Reading Cookies on Server

Using the cookie-parser middleware:

const userId = req.cookies.userId;
console.log(`User ID from cookie: ${userId}`);

Step 4: Creating Cookies with JavaScript

document.cookie = "theme=dark; max-age=3600; path=/";

Step 5: Deleting Cookies

Set expiration date in the past:

document.cookie = "theme=; expires=Thu, 01 Jan 1970 00:00:00 UTC; path=/;";

Step 6: Implement Security Best Practices

• Always set HttpOnly and Secure flags where possible.
• Use SameSite attributes to reduce CSRF vulnerabilities.
• Avoid storing sensitive information directly in cookies.

Step 7: Respect Privacy Regulations

• Implement consent banners.
• Provide users with options to manage cookie preferences.
• Document cookie usage in privacy policies.

Advanced Topics and Considerations

1. Cookie Size and Limits

• Most browsers limit individual cookie size to 4KB.
• There is a per-domain cookie limit (around 20–50 cookies).
• Exceeding limits causes older cookies to be evicted.

2. Third-Party Cookie Restrictions

• Browsers increasingly block or restrict third-party cookies.
• Alternatives include localStorage, IndexedDB, or server-side sessions.

3. Alternatives to Cookies

• Web Storage API (localStorage, sessionStorage) for client-side storage.
• JWT tokens for stateless authentication.

4. Cross-Origin Resource Sharing (CORS) and Cookies

• Cookies require careful configuration of CORS headers and credentials policies to work across domains.

The post Understanding Cookies: Concepts, Use Cases, Architecture and Getting Started appeared first on scmGalaxy.

1. Node.js

Node.js is a runtime environment that allows JavaScript to be used for backend development. It features an event-driven, non-blocking I/O model that makes it lightweight and efficient for building scalable network applications. With an extensive package ecosystem (npm), it supports microservices, real-time applications, and server-side APIs. Node.js enables asynchronous programming, making it an excellent choice for applications that require high concurrency, such as chat applications and live streaming services.

2. Express.js

Express.js is a minimal and flexible Node.js web framework that provides a robust set of features for building web and mobile applications. It simplifies routing, middleware integration, and API development, making it a preferred choice for lightweight backend development. Express is widely used in MEAN (MongoDB, Express, Angular, Node.js) and MERN (MongoDB, Express, React, Node.js) stacks, providing fast and scalable RESTful APIs.

3. Django

Django is a high-level Python web framework that promotes rapid development and clean, pragmatic design. It includes an ORM, built-in authentication, and security features to prevent common vulnerabilities like SQL injection and cross-site scripting (XSS). Django follows the “batteries-included” philosophy, offering built-in tools for user authentication, database migrations, and an admin panel for managing content.

4. Flask

Flask is a lightweight Python framework that offers flexibility and simplicity. It provides essential tools for web development while allowing developers to add extensions as needed. It is ideal for small projects and microservices. Flask’s modular architecture allows developers to choose third-party libraries for functionalities like authentication, form validation, and database integration, making it an excellent choice for developers who prefer minimalism and flexibility.

5. Ruby on Rails

Ruby on Rails is a full-stack web application framework written in Ruby. It follows the convention over configuration (CoC) principle, allowing developers to build applications quickly with less code. Rails provides built-in features such as Active Record ORM, automated testing, and a robust asset pipeline, making it a favorite choice for startups and rapid prototyping.

6. Laravel

Laravel is a PHP framework designed for modern web application development. It features an elegant syntax, a powerful ORM (Eloquent), built-in authentication, and a templating engine (Blade), making it one of the most popular PHP frameworks. Laravel also includes tools for API development, job scheduling, and real-time event broadcasting using WebSockets.

7. Spring Boot

Spring Boot is a Java-based framework that simplifies the development of enterprise applications. It offers an extensive ecosystem for building microservices, RESTful APIs, and large-scale applications with minimal configuration. Spring Boot’s built-in dependency management, security features, and integration with cloud platforms make it a leading choice for enterprise applications.

8. ASP.NET Core

ASP.NET Core is a cross-platform, high-performance framework developed by Microsoft for building modern web applications and APIs. It supports dependency injection, cloud-based deployment, and high scalability. ASP.NET Core integrates seamlessly with Microsoft Azure and offers built-in support for identity management and security.

9. FastAPI

FastAPI is a modern, high-performance web framework for Python. It is designed for building APIs with automatic OpenAPI documentation, data validation, and asynchronous request handling. FastAPI is built on Pydantic and Starlette, providing excellent support for asynchronous programming and real-time applications.

10. Koa.js

Koa.js is a lightweight web framework created by the same team behind Express.js. It provides a smaller, more expressive core and allows developers to use middleware for added functionality. Koa’s modular design enables developers to choose their own middleware, making it an excellent choice for applications that require fine-grained control over request handling.

11. NestJS

NestJS is a progressive Node.js framework built with TypeScript. It supports modular architecture, dependency injection, and an extensible ecosystem for developing scalable and maintainable applications. NestJS is widely used for enterprise-grade applications, offering built-in support for GraphQL, microservices, and WebSockets.

12. Strapi

Strapi is an open-source headless CMS based on Node.js that enables developers to build customizable APIs quickly. It supports GraphQL and REST, making it a great choice for content-driven applications. Strapi provides an intuitive admin panel, role-based access control, and extensibility through plugins, making it a powerful tool for managing digital content.

13. AdonisJS

AdonisJS is a full-featured Node.js framework inspired by Laravel. It provides an intuitive ORM, authentication, and structured MVC architecture for developing web applications efficiently. AdonisJS offers built-in support for dependency injection, WebSockets, and database migrations, making it a strong alternative to Express.js for full-stack development.

14. Hapi.js

Hapi.js is a powerful and secure Node.js framework that offers rich features for API development, authentication, and input validation. Hapi’s modular plugin-based architecture allows developers to build scalable and maintainable applications with built-in support for caching, authentication, and real-time data handling.

15. Phoenix

Phoenix is an Elixir-based framework designed for building scalable and maintainable applications. It features real-time WebSocket support, high concurrency, and fault tolerance. Phoenix uses the Erlang VM for high availability and supports LiveView, which enables real-time UI updates without JavaScript.

16. CakePHP

CakePHP is a PHP framework that follows the MVC pattern. It simplifies database interactions, validation, and security features, making it ideal for rapid web application development. CakePHP’s built-in ORM, scaffolding, and authentication system speed up development while maintaining security.

17. Micronaut

Micronaut is a modern Java framework designed for building microservices. It features low memory consumption, fast startup times, and built-in cloud support. Micronaut’s annotation-based configuration system and ahead-of-time (AOT) compilation make it an efficient choice for cloud-native applications.

18. Play Framework

Play Framework is a reactive web application framework for Java and Scala. It provides a stateless architecture, making it ideal for high-performance applications. Play’s asynchronous programming model and built-in WebSockets support make it a strong choice for real-time applications and microservices.

19. Fiber

Fiber is a web framework for Go that is inspired by Express.js. It offers fast performance, easy routing, and built-in middleware support. Fiber is designed for high-speed API development, leveraging Go’s concurrency model to handle multiple requests efficiently.

20. Revel

Revel is a full-stack Go framework that includes built-in routing, validation, and templating features for rapid development. Revel’s hot-reloading feature allows developers to see code changes instantly, improving development efficiency.

21. Rocket

Rocket is a web framework for Rust that focuses on speed, safety, and ease of use. It provides automatic type-safe request handling and is designed for secure backend applications. Rocket’s compile-time checks and built-in database integration make it a strong choice for developers looking for high-performance and secure web applications.

The post Top 21 Tools for Backend Development Frameworks in 2026 appeared first on scmGalaxy.