Use cases for HTML's Web Storage API
Published: 2023-07-18 19:14:30

by [John Abraham](https://blog.openreplay.com/authors/john-abraham)

<blockquote><em>There are various ways you can leverage web storage in your web applications. Front-end developers use the modern browser web storage API to create more personalized, efficient, and responsive websites. This article will explore many use cases that can help you create engaging web apps.</em></blockquote>




HTML5 web storage API is a storage mechanism that allows a web application to store data locally on the client side. The data is stored within the user’s web browser. It works like cookies but with a larger storage limit and stronger API. The limit of HTML5 storage is at least 5MB. This limit is larger compared to cookies with a limit of only 4KB per domain. There is widespread browser support for this API.


## Overview of HTML5 Web Storage API

HTML5 web storage API helps improve a website's performance by making it faster. This is because web storage has large client-side storage space for data. The large storage space allows a web app to work seamlessly with stored data to provide an engaging experience for a user.

There are two types of storage under HTML5 web storage, known as `localStorage` and `sessionStorage`. They both play different roles in storing data on a user’s web browser. So, what are the `localStorage` and `sessionStorage` APIs? How are they different from each other? Let’s have a look:

- `localStorage` API: It provides an interface for web applications to store data permanently. This means the data persists beyond the current browser session. Even when you close the tab or browser, the data storage will not be cleared. The local storage object allows developers to retrieve and remove data using unique keys.

- `sessionStorage` API: This web storage API provides a convenient way to store data temporarily. The data lasts as long as the browser tab or browsing session is active. This API is best used to store temporary information only needed during a single session.

`localStorage` and `sessionStorage` store data in key/value pairs. Developers can use these keys to interact with stored data. To store data in `localStorage`, you can assign it a unique name (key) and associate this key with a value. For example, you can store a name like this:
```javascript
//storing data using localStorage
localStorage.setItem(‘name’, ’Josh’);
```

You can store several types of data, like texts, objects, and numbers. You can also retrieve this data using the associated key. For example, you can retrieve the data like this:
```javascript
//retrieving data from localStorage
const name = localStorage.getItem(‘name’);
```

You can also remove stored data in localStorage like this:
```javascript
//removing stored data
localStorage.removeItem(‘name’);
```

`localStorage` and `sessionStorage` work similarly and follow the same code lines. If you plan on implementing `sessionStorage`, you must replace the `localStorage` object in the code above with `sessionStorage`.

The primary difference between the two storage APIs is that data is stored permanently using local storage and temporarily using session storage. The possibilities of HTML5 web storage API are endless if you apply them creatively. In the next section, we will look at the several use cases of both `localStorage` and `sessionStorage` APIs.
## Use Cases for Local Storage API
Local storage API gives you a long list of use cases you can benefit from. These use cases range from storing user preferences to creating a real offline experience and many more. Let’s have a look at these use cases:

1. **Saving User Preferences:** Local storage API offers a robust solution to storing user preferences. It offers language options for you to pick your preferred language. It also stores preferences like the theme (light or dark), font size, etc. These preferences are saved after you close a page and can be retrieved once you’re back.

2. **Creating a Personalized User Experience:** The personalized user experience usually comes from the ability of Local storage API to save user preferences. It stores data about your habits and interests to create an environment perfect for you. For example, an e-commerce site can save the type of product you viewed and provide recommendations on your future visits.

3. **Storage of Data for Online Use:** Local storage API leverages cache data to help give you access to certain parts of a website while offline. This is most applicable to websites that have static content with fewer changes. You can also read articles on a web app while offline, and when the connection is restored, the app will sync the updates.

4. **Storage of Game Data for Browser-based Games:** You can easily save game achievements and progress using Local storage API. It saves player names, high scores, and other relevant information. This way, you can continue a game from where you left off instead of starting again.

5. **Retaining Session States:** You can retain a session state if your browser closes while filling out a form or creating an online document. The unfinished task will be restored once you regain connection.

`localStorage` stores extensive size of user data, including the user's mailbox and authored documents. The ability for `localStorage` to save data permanently makes it perfect for improving the performance and personalization of a web app to a user.




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## Use Cases for Session Storage API

The `sessionStorage` API is ideal for use cases where data is only needed temporarily. Depending on what you are trying to build on a web app, you can leverage session storage for several use cases. Let’s explore some of them:

1. **Storage of Data Temporarily During Sessions:** `sessionStorage` stores temporary information that is important and related to your interaction on a web app. This includes data like preferred UI, language, and dynamic settings. This data will be made available throughout your session and will be lost once the session ends.

2. **Maintenance of Data Consistency Across Multiple Windows or Tabs:** If you open multiple tabs on a web app, session storage syncs the data between all opened tabs. If you add an item on one tab, you will sync with the others.

3. **Storage of Data During Form Completion:** If you accidentally close a form while filling it out in a browser window, session storage API lets you kick off from where you stopped. Each field’s value is stored as you complete the form and will still be available once you lose and regain connection.

4. **Efficient and Fast User Authentication:** `sessionStorage` temporarily stores authentication tokens after you log into a web app or site. This authentication token helps to verify your status throughout an interaction. You don’t have to continuously input and confirm your details.

Regarding getting rid of sensitive data, `sessionStorage` plays a key role. Storing sensitive information locally can be a security risk if you're not careful. `sessionStorage` helps to mitigate these risks by deleting sensitive data (potentially personal information) immediately after a session closes. 
## Conclusion

In front-end development, the use cases of HTML5 web storage span various areas. They range from saving data for offline use to creating a personalized experience on web apps and so on. All these use cases work together to provide a smooth experience for anyone using your web apps.

When you leverage the HTML5 web storage API, you will create web apps that resonate well with a wide audience. It is important to note that `localStorage` and `sessionStorage` APIs should be used where they will give optimal results. Using `sessionStorage` where you should have used `localStorage` can be a bit messy for users.