Browser Cache and Cookies: What are they and how do they differ from each other?

Browser cache

If you’ve been surfing the internet, you must’ve come across the terms browser cache and cookies. They’re quite common and most websites these days ask for your permission to store cookies on your device.

Both these technologies are a way of storing data from your website on a visitor’s local device. They both store different types of information and are used for different purposes.

In this article, we’ll take a look at what browser cache and cookies actually are. Then, we’ll try to understand the difference between the two to gain a better understanding.

What is Browser Caching?


Simply put, Caching something means temporarily storing data in a spot that makes for easier/quicker retrieval.

There are a few different ways in which you can cache your WordPress website. In this article, we’re focused on one specific implementation, that is, the browser cache.

Let’s try to understand this by taking a simple example. Your site has a lot of static files that won’t change from visit-to-visit. One of the most common examples would be your site’s logo. Most likely, you won’t change your logo that often. Also, your logo is likely the same on all or most of your site.

So if a user visits three separate pages on your site then it’d surely be a waste to force that visitor to download the exact same logo file three times in a row.

The browser cache lets you get around such situations by storing these static files on a visitor’s local computer. So with the browser cache, it would work like this instead:

  • First visit: The visitor’s browser downloads the logo file from your server and saves it locally in the browser cache.
  • Subsequent visits: The visitor’s browser loads the logo from the visitor’s local storage, or the browser cache, instead of downloading the logo again.

This makes your website loads faster on all subsequent visits, which is a great advantage.
You can also set expiration dates to control how long a visitor’s browser stores certain types of files. So, you can tell a visitor’s browser to store all JPEG images for 4 months, but only store MP4 videos for 1 month!

Moreover, if you do need to change a file before the expiration is up, you can employ a technique called cache busting to force visitors’ browsers to download the most recent version of a file.

Uses of Browser Cache

Browser cache lets you store certain static files like images, videos, CSS/JavaScript, etc. This is a one-way relationship. Those files don’t communicate back to your server once they’re stored. Moreover, the browser cache does not identify specific users and treats all users the same.

The browser cache helps you speed up your site and lessen the load on your server.

What is a Cookie?


A cookie is a small file that is stored on a visitor’s device and contains data specific to a particular client. Here, ‘client’ refers to the device of the person who is visiting your site.

Cookies help you store useful information about a visitor, like their login information/authentication, or the items in their shopping cart. They can also help track and identify visitors, even between different website visits.

Cookies are only used to store text-based data, like IP addresses, session IDs, visit histories, and more. You cannot use cookies to store an image, as you can do with browser cache.

Moreover, browser cache is a one-way transfer, that is, from the server to the local cache. Whereas, a client’s web browser will send the cookie to your web server on every visit, so the information can go from both Server to Client and from Client to Server.

Types of cookies:

Persistent cookie: This type of cookie has an expiration date, but it stays on a visitor’s local machine while active and persists between visits to your website. It lets you identify a visitor even if they leave your site and then return.

Session cookie: This type of cookie is stored in memory. It is never saved to your visitor’s local machine. A session cookie is active during a visit, but as soon as your visitor closes their browser, it is permanently gone.

Uses of Cookies

Cookies are small text-based files that enable you to track, identify, or otherwise store information that is unique to each visitor. Unlike browser cache, this is a two-way relationship where your server is able to read the information from the cookie.

Cookies help you provide better user experience. You can recognize whether a user is logged-in or identify a visitor to show them the items in their shopping cart in an eCommerce store.

Cookies can also help you track and identify specific visitors. For example, you can set up a cookie so that your site doesn’t display an email opt-in popup after a visitor has already subscribed to your email list.

Lastly, you can even use cookies to assist with off-site functionality. For example, you can set a retargeting cookie so that you can display ads to your site’s visitors even when they’re on other sites.

Final Words

Both browser caching and cookies let your store information on a visitor’s computer. However, they have different purposes and they do it in different ways. Browser caching helps you speed up your site.

On the other hand, cookies help you store information about specific users to identify or track them.

Got any questions regarding browser cache and cookies? Let us know in the comments below. You can also write to us for more detailed and personalized queries.

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