ASP.NET Cookies

Cookies offer a valuable feature that allows for the storage of modest data volumes on the client's machine. They are commonly employed to preserve user preferences, session variables, or identity-related information. When a user revisits a particular website, the stored data can be retrieved by the application, facilitating a personalized experience based on previous interactions.

The management of cookies on a user's system is handled by the web browser. Cookies can be created, accessed, and modified directly by client-side scripts, facilitating seamless communication between the client and server during various requests.

Writing Cookies

Response.Cookies["userName"].Value = "John"; Response.Cookies["userName"].Expires = DateTime.Now.AddDays(1);
Response.Cookies("userName").Value = "John" Response.Cookies("userName").Expires = DateTime.Now.AddDays(1)

Reading Cookies

if(Request.Cookies["userName"] != null) Label1.Text = Server.HtmlEncode(Request.Cookies["userName"].Value);
If Not Request.Cookies("userName") Is Nothing Then Label1.Text = Server.HtmlEncode(Request.Cookies("userName").Value) End If

Cookies can be classified into two types:

Temporary cookies

Temporary cookies are stored in the client's browser and are available only while the web browser is running. They are typically used for session management and are deleted when the browser is closed.

Persistent cookies

Persistent cookies, on the other hand, are stored as text files on the hard disk of the client's computer. These cookies remain on the hard disk even after the browser is closed and can be accessed by web servers on subsequent visits. They persist until they are manually deleted or reach their expiration date. Persistent cookies are commonly used for long-term user preferences and personalized experiences.

Cookies | Advantages

Cookies offer several advantages, including:

  1. Persistence: Cookies can persist data across multiple requests and sessions. Once set, cookies remain on the client's machine until they expire or are deleted.
  2. Client-side storage: Cookies are stored on the client's machine, reducing the need for server-side resources to maintain user-specific information. This can improve scalability and reduce server load.
  3. Customization: Cookies can store various types of data, such as user preferences, shopping cart contents, or authentication tokens. This allows for a personalized and customized user experience.

Cookies | Limitations and Considerations

It's important to consider the following limitations and considerations:

  1. Size limitations: Cookies have a maximum size limit of 4KB. Storing large amounts of data in cookies can lead to performance issues and potential data loss.
  2. Security: Cookies are stored on the client's machine and are susceptible to tampering. Sensitive data should be encrypted or avoided in cookies to mitigate security risks.
  3. Browser restrictions: Some browsers have limitations on the number of cookies allowed per domain. It's important to be mindful of these restrictions when implementing cookie-based solutions.


Cookies can be temporary or persistent, with temporary cookies being stored in the browser during the browser session, and persistent cookies stored on the client's hard disk. They have size limitations of 4096 bytes and are typically used for storing string-based data. Browsers impose restrictions on the number of cookies a site can store, often allowing a maximum of 20 cookies per site.