Session Cookies vs Persistent Cookies: What are the Differences

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Internet cookies may all look the same. They’re small text files a website uses to store some data on the user’s device. But these cookies come in various forms and, more importantly, serve different purposes.

This article will delve into the differences between session cookies vs persistent cookies. You’ll learn about their advantages and disadvantages, how they may affect the privacy and security of your consumers when visiting your website, best practices for cookie consent management, and more.

So, let’s start.

What are Session Cookies?

A session, or a transient cookie, stores information about a single user session on a website. These cookies are temporarily stored on the visitor’s computer or device memory, which is automatically destroyed when the user closes their browser.

The primary purpose of a session cookie is to simplify user navigation by making web pages load faster. Because of this, session cookies are usually enabled by default on websites, especially e-commerce ones.

Of course, a user can manually disable or restrict the use of these cookies while browsing the pages since these are not strictly necessary cookies.

These cookies can have a positive and negative side to them:

  • Positive:

They improve the user’s experience during a session while having minimal impact on the user’s privacy and security, and they don’t take up storage space on the user’s device.

  • Negative:

If the user doesn’t save their data before closing the browser (perhaps by accident), this can lead to data loss and a negative user experience.

What are Persistent Cookies?

Persistent cookies are a type of cookies that remain stored on the user’s device even after they close the browser.

These cookies last only a limited time since their duration is determined by the Max-Age or Expires attribute. This differs from session cookies, as persistent cookies can remain stored on the user’s device even after the user closes the browser.

Persistent cookies are stored on the user’s hard disk drive (HDD). Their exact location will depend on the operating system (OS) and the Internet browser.

Here’s where you can find persistent cookies depending on your OS and web browser by default:

  1. Windows:
  • Google Chrome: **\\App Data\\Local\\Google\\Chrome\\User Data\\Default\\
  • Mozilla Firefox: **\\App Data\\Roaming\\Mozilla\\Firefox\\Profiles\\
  • Microsoft Edge: **\\App Data\\Local\\Microsoft Edge\\User Data\\Default\\
  1. macOS:
  • Google Chrome: ~**/Library/Application Support/Google/Chrome/Default/
  • Safari: ~**/Library/Cookies/
  • Mozilla Firefox: ~**/Library/Application Support/Firefox/Profiles/
  1. Linux:
  • Google Chrome: ~**/.config/google-chrome/Default/
  • Mozilla Firefox: **~/.Mozilla/Firefox

Since they are more permanent, persistent cookies have a positive and a negative side:

  • Positive:

It creates a smoother experience for the user if they return to the website after closing the browser. Theoretically, no official limit exists on how long these cookies can last, although the browser or server may impose practical limits. Of course, if the limit isn’t specified, then these become session cookies instead.

  • Negative:

The longer the duration of the persistent cookie, the more significant its impact on the user’s privacy and security will be. Also, since the cookie has to be stored for a more extended period, it will take up more storage space.

Differences Between Session and Persistent Cookies

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The main difference between session and persistent cookies is that session cookies last only until the user closes their web browser. Unlike them, persistent cookies remain in the device memory even after the user closes their web browser.

Of course, this isn’t the only difference between the two. Here are the critical differences between session vs persistent cookies:


Session cookies last only while the user has the web browser open. When this happens, the cookie is automatically deleted from the user’s device.

Persistent cookies can last after the user closes the web browser.

Expiration Date

Session cookies have no set expiration date or time.

Persistent cookies specify the expiration date in the Expires or Max-Age attribute. There is no maximum expiration date, although, in practice, this is limited by the web browser or server.

Data Storage

Session cookies don’t take up the user’s storage space. Since this is a temporary file, they are stored in the cache memory and are deleted when the session ends (the user exits their browser).

On the other hand, persistent cookies are stored permanently on the user’s hard disk drive until their expiration date, or the user manually deletes them.

Data Privacy and Security

Typically, session cookies have little impact on the user’s privacy, as they are deleted automatically when the user closes the browser.

However, persistent cookies are another matter. Setting a longer expiration date can lead to several privacy concerns, such as:

  • Potential non-compliance with data privacy regulations:

Many privacy laws, like the GDPR, require users to provide informed consent for cookies that can be used to identify them, which is the case with persistent cookies.

Also, since the data about the user should be stored for only as long as this is required by a specific purpose, setting longer persistent cookies must align with the GDPR’s principle of storage limitation.

  • Security risks:

Although this is against the accepted best practice, sometimes, persistent cookies can contain sensitive information about the user or are used for authentication.

In that case, a malicious actor, like a hacker, can misuse this cookie if they manage to get into its possession. This can lead to session hijacking, unwanted actions on the users’ behalf, and data privacy breaches.

Websites and third-party advertisers can also use persistent cookies to track users’ online browsing activities over time.

They can then compile this data for profiling based on the user’s interests, habits, and behaviors and send targeted ads to the user without their consent.

  • User awareness and control:

Although the GDPR and similar regulations require website owners to provide transparent information regarding their use, purpose, data collection, or how to manage and delete them, that’s not always the case.

Users might need to be made aware that a persistent cookie is stored on their device or its purpose.

Information Stored

Session cookies store limited information, only the unique session identifier. On its own, the session ID is a randomly generated string. However, it can link back to other information about the user, such as authentication status, user preferences, form data, shopping cart contents, or page visit history.

Persistent cookies store different data that can improve the user’s experience on the website. This includes user preferences, authentication data, shopping cart contents, session management data, ad targeting data, and tracking & analytics data.

Some of this data can be misused, as we have mentioned already.

For instance, if persistent cookies are used for authentication, hackers can use them to log into the website using the user’s credentials. Or, if persistent cookies are used for tracking and analytics or ad targeting data, they can be used by third-party advertisers to track the user and for profiling without their explicit consent.

Frequently Asked Questions (FAQs)

The main difference between persistent and session cookies is that a session cookie is deleted automatically when the user closes their web browser.

On the other hand, persistent cookies remain stored on the user’s device until their expiration date ends. This is specified in the Max-Age or Expires attribute.

Typically, session and cookie have different roles, where “session” is server-side storage, and “cookies” are client-side storage.”

Generally, a session is considered more secure because of the limited exposure to sensitive information. Namely, most of the data, except for a session ID (a random string), will remain on the server, which limits the risk of exposure to sensitive information.

Also, if the session identifier stored in the cookie is secured with attributes such as SameSite, HttPOnly, or Secure, this further reinforces the session’s security.

The main differences between a session and a tracking cookie are their purpose, data storage location, and lifetime.

  • Purpose:

A session keeps the users’ data and state of affairs while they are on a specific website. The session typically ends when the user closes the website.

Tracking cookies can work on multiple websites and across devices. Their primary purpose is to monitor the user’s behavior over time for analytics and advertising.

  • Data storage location:

Sessions are stored on the server side. Only the session ID is sent to the client’s browser as part of the session cookie.

Tracking cookies are stored on the user’s device (client-side).

  • Lifetime:

Any data created for a session is typically deleted once that session ends (after a period of inactivity or when the user closes the website or browser).

Tracking cookies, on the other side, are not limited to the duration of a session and can last multiple sessions or if the user closes and then reopens the web browser.

Of course, both of these cookies can be first-party or third-party cookies, depending on who sets them.

Using cookies instead of relying on sessions allows website owners to keep user-specific information directly on their browsers. This means they are usually not limited to a specific request or session.

As such, cookies can reduce server load, simplify session management, improve client-side functionality, and more.

What do Persistent Cookies Expire?

These cookies last only a limited time since their duration is determined by the Max-Age or Expires attribute. This differs from session cookies, as persistent cookies can remain stored on the user’s device even after the user closes the browser.

How Can Captain Compliance Help You?

Website cookies can often be confusing as their purpose or how they affect the user is only sometimes evident. Simply put, there are so many types of cookies to keep track of, which can be challenging.

At Captain Compliance, we aim to simplify data privacy compliance for businesses.

If your business uses session or persistent cookies, you may need to take certain compliance measures to ensure you’re on the right side of the law.

Get in touch today for a consultation to find out what you need to do.

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