With the growing number of websites and Internet users, the requirements for good user experiences, security, and conveniences have also increased. Regular web pages with basic usability or even a lack of features can make the users turn away and abandon the site very quickly. To lead the web world, many businesses use new web technology to create robust interfaces that better serve their users. One of these is the Single Page Application used by Netflix, Airbnb, PayPal, and many more. So what is Single Page Application? How does it work? What are the pros and cons of SPA? Will it become the future of the web world?   

What is Single Page Application

Let’s get started with understanding the single page application definition. A single page application (SPA) is a website or web application capable of rewriting its current web page with data retrieved from a web server instead of loading the entire page. In other words, some information will be updated if a request is made, while others stay unmodified.   

For example, while using email, the header and side toolbar remain stationary when browsing through the inbox list, typing a new email, or reading the received one. With each click on an email or an attached file, the web single page application will send the needed information or perform the required act, both of which are rendered by the browser. This differs from the traditional web page as it doesn’t need to reload the whole page per click.   

This client-side-friendly attempt helps users access and browse websites much faster. It also relieves the burden of the back end as the server system processes a much lighter amount of information, thus cutting down unnecessary costs.   

SPA is not something new. They are around us, and most of them are used regularly. To help you recognize, here are some famous single page application examples:  

• Gmail: Open, read, unread, compose, send, and delete emails;  
• Grammarly: Get grammar corrections and suggestions on your writing; 
• Google Maps: Search for directions or specific locations. 

A Brief Single Page Application History

How did we even come up with SPA? The earliest history of single page application was coined around the early 2000s. However, the origin of the term remains unclear. One thing we can all be sure about is that it was born after multiple-page web applications (MPA) or traditional web apps. The MPA’s predecessor model has been challenged with data overprocessing and complex UI design.

Even though solutions like AJAX have been created to tackle the said issues, user experience on websites still got side effects along. Single-page applications were made later and revolutionized the MPA+AJAX pattern. Read this blog to better understand the differences between SPA vs MPA or simply what to choose for your development.

Stuart Morris, a programming student at Cardiff University, created the first SPA prototype. In April 2002, he wrote the Self-Contained website at slashdotslash.com. Later in the same year, Lucas Brideau, Kevin Hakman, Michael Peachey, and Clifford Yeh first mentioned its concept in the US.   

The integration of JavaScript allows single page apps to display dynamic user interfaces, run application logic, and communicate with web servers. Code developers can lessen the amount of JavaScript code they have to write, as there are numerous mature free libraries for SPA development. 

Explained: How Single Page Application Works

SPA eliminates the need to load several web pages from the server and automatically rewrite the current page to keep users engaged.   

Each SPA website contains a specific URL. The content is downloaded within the website, and specific components of the user interface will be updated when clicked. To be more precise, when clicking on one of these components, data will be fetched from the server for an update. For the initial client request, some relevant assets for information load-up are HTML, CSS, JavaScript, etc. This initial load file can be substantial for sophisticated programs, leading to delayed loading time. As a user navigates through the single page app, an application programming interface (API) retrieves fresh data. These retrieved data will only be returned in JavaScript object notation (JSON) and used for the update. The said update results in updating new content on the current page without completely reloading the page.   

Single page apps architecture comprises two rendering technologies for the server and client sides. After rendering, the web app will be presented to the user through these gateways: 

• Client-side rendering: This rendering style allows the server to receive an HTML file with connected scripts and styles after requesting one. A loading graphic or blank page appears when JavaScript executes the request. Then, the single page application shall collect data, arrange views, and surge the data into the Document Object Model (DOM). This is when it is ready for use. Among the three approaches of single page application architecture, client-side rendering is the longest and prone to browser overload due to the extensive usage of device storage for content display. Furthermore, CSR is a viable option for high-traffic websites because it delivers information to customers without requiring unnecessary server connectivity, resulting in a faster user experience;  
• Server-side rendering: Browsers in server-side rendering also request an HTML file as client-side rendering does. The only difference is that the server will retrieve data, render the single page apps, and immediately create a specific file for the application. All the accessible material will be presented to the user. It is ready for usage once the single page application architecture has attached events, produced a virtual DOM, and execute additional tasks. Server-side rendering combines the speed of a SPA with the prevention of overburdening the user’s browser, resulting in a better speed of the program;  
• Static site generator: Browsers are more likely to make a request to the server for an HTML file instantly and right inside the static site generator. With this, the single page application is ready to use when the data has been fetched, views have been generated, and both are injected into the DOM. From the name, this gateway is the most suitable for static pages as it provides a fast option. 

For the best display of dynamic content on the website, it is advised that you should use either client-side or server-side rendering. 

Advantages of Single Page Application

1. Functionable despite disruption or offline  

Effective local data caching is the first beneficial single page application feature. After sending the request to the server, the necessary data will be archived and stored in cache.  

This data will be utilized and used even for the offline function. If the user suffers from any reduced Internet connection, the local data will put its synchronization process to a halt until the connection is patched. 

2. Fast processing 

We already know that SPA only updates certain content on the page, not the entire page. This feature has optimized the website’s loading speed, as data is the only component being exchanged between the client and server sides. Other components like CSS, scripts and HTML are only loaded once throughout the working time of the application. Fast processing time can boost sales and business impressions.   

3. Enhanced user experiences  

This is one of the most outstanding single page application features. Users can get all the content displayed simultaneously once granted site access. This feature has allowed them to scroll on their devices more comfortably and less likely to be interrupted. SPA also delivers the feel of a mobile or native desktop app, which makes it simple to use.   

Unlike MPA, users can instantly reach their desired content without clicking multiple links. This results in lower bounce rates and less frustration with loading time. The UX of SPAs consists of distinctive beginning, middle, and conclusion stages, making them more favorable to users. 

4. Cross-platform compatibility  

From only a codebase, SPA developers can build applications that can run on any device, browser, and operating system. The said application enhances the user experience since it is accessible at any location.    

The compatibility with multiple platforms allows developers and DevOps engineers to create feature-rich apps, such as real-time analytics while creating content editing applications. 

5. Quick development  

SPA usually has a separate front-end and back-end, known as a decoupled setup.   

The decoupled setup helps businesses keep raw content, data, and basic functions of the website (logging in, registering, checking, etc.) the same. At the same time, it allows developers to build, deploy, and experiment front-end without interfering with the back-end technology.    

The quick decoupling setup is done using APIs that determine the data structure. The design will be crafted in specific ways to stimulate user flow, while content and data functions will be pulled in later. 

6. Chrome-based debugging 

Single page application can be debugged on Chrome if it is built on frameworks like Angular, React, and VueJS. Debugging SPA is much easier than a multi-page application since its frameworks are mostly equipped with Chrome developer tools. Instead of going through lines of code, developers can examine the JS code rendering from the browser and debug SPAs. 

Disadvantage of Single Page Application   

There are still existing single page application cons that you or any new developers should look out for. 

1. No storage for browser history 

Browsers usually store the history of pages, not the states of the website. If users click Return on the browser toolbar, the previous state of the application will not be retrieved. To tackle this issue, developers are suggested to prepare an HTML5 API. This API shall give developers access to the history of the browser’s navigation through JavaScript. You can create an undo button within the pages to help users navigate back and forth. 

2. Challenging Search Engine Optimization 

Businesses are investing in a slot on Google’s first and second pages, simply because users will mostly click on the first. Optimizing Core Web Vitals for better SEO is extremely important. However, this doesn’t work for the case of SPA as its rendering limits SEO.  

The function of SPA makes the URL unchanged and diverse pages within it unequipped with exceptional URL addresses. Search bots cannot find these internal pages.   

To change this, a scheme has been launched by Google to index active pages. To have SPA indexed, the JavaScript files must be indexed through Google, which requires that the website must use HTML 5 mode in the URL structure. 

3. Vulnerability to cyber attacks 

Without protection from cross-site scripting (XSS) attacks, SPA is more prone to attack than MPA. Hackers can exploit the XSS to insert client-side scripts into web apps. Another security problem is the disclosure of sensitive data. Developers might accidentally send data that is meant to be kept from the public.   

The absence of operational-level access control is another reason SPA can easily be hacked. Be caution when developing SPA, as one mistakes can open to various of exploitation.  

How Does Single Page Application Benefit Business And User  

To Business 

The best single-page application benefit for business owners and their companies is time-efficient. Its information flow is also simplified for easier creation of an authentic mobile application, thanks to the application of back-end API on both the web and mobile.   

Single page applications are usually optimized in terms of speed; therefore, businesses can respond to their customers smoother and faster. 

To User 

Users are the ones that benefit the most from SPAs. They can enjoy certain single page application benefits, from speed loading optimization and the ability to work offline.   

As users are spending most of their time on their cellphones, single page applications are on the rise. The UI design of SPA makes it easy to scroll on mobile devices and request little to no clicking on links. 

When Should You Use SPA? 

We have known the pros and cons of single-page applications, and now it’s time to put them into proper use.  

If you want to build a platform that contains a small amount of data or is mainly static, SPA can be the best choice.  

If you intend to build a mobile application in the future but have limited resources, you can try SPA first. SPA’s back-end API can be utilized for both the site and the mobile app. 

The single-page application architecture is the most suitable for SaaS platforms, social networks, and secluded communities. Some common examples of this application are Google Maps, Gmail, and Facebook. In the case of Google Maps, live changes are made when the user moves from one place to another, helping them quickly identify their location. Live updates are another fascinating feature of single page applications and can be used for data streaming, real-time charts, notifications, and so on.   

On the other hand, if SEO is what businesses and organizations concentrate on, a single page app is not the optimal choice. Instead, they can consider a multiple-page application.

Top Frameworks For Single Page Application Development 

Most SPAs are built with JavaScript. Here’s our suggestion on the top Single Page Application Frameworks to use 

• ReactJS: this is the top recommendation framework for single page application development. It allows developers to work more flexibly and effectively with multiple side functions;  
• AngularJS: as one of the earliest frameworks, AngularJS is the best option for building client-side applications with performance optimization;  
• EmberJS: This is the open-source solution for effective UI transmission, secured in-app user interface development, and developer-friendly application programming interface;  
• BackboneJS: If you are looking for something lightweight and flexible, Backbone JS is the one, as it can create a flexible single page application in a well-structured format. Extra plug-ins can be installed to your liking;  
• VueJS: A well-known single page application framework for creating high-performance web apps with cost efficiency. It also works as a library that stores platform types serving for development;  
• Meteor: Free, open-source, and full-stack are three words that best describe Meteor. It is known as a multifunctional package for easy collaboration between the server and client;  
• Polymer: Polymer provides developers with compact single page application development, end-to-end testing environment, and one-way and two-way binding;  
• Dojo Toolkit: Compared to the aforementioned frameworks, Dojo Toolkit is more of an expert-level framework with complicated and scattered documentation. The recent update has made it easier for modern web and single page application development.  
• Aurelia: Aurelia is another excellent choice for a simple and easy-to-use SPA framework. It can support modern browsers with a wide range of flexibility and cooperate well with other counterparts and third-party tools.  
• Svelte: Concluding the chart, Svelte supports constructing dynamic user interfaces and less complicated application development syntax.   

We have list down these 10 best to use single page application frameworks with detailed review on main features, pros & cons or pricing!

Q&A About Single Page Application  

Wrapping Up 

Single page application is no strange concept; it appears mostly everywhere near us today. With the help of SPA, we can create a functional web application that fasts loading and save time with little disturbance. By the end of this blog, Synodus hope that you fully figure out single page application meaning and its characteristics.

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