Single Page Application (SPA) is a modern type of web application in which all the resources necessary for the application to work are loaded once according to the SPA architecture. Traditional websites differ from them in that every time a user navigates to a new subpage, the site has to load all the elements from scratch. With SPA sites, the user's experience of the application is smoother, as all actions are performed on a single page, eliminating the need to reload the entire document.
When the user performs an action, SPA updates only selected parts of the interface, while the rest of the page remains unchanged, which significantly affects the speed of the application. A web application in the SPA model allows for dynamic content loading, which is crucial when creating dynamic user interfaces. This greatly improves the user experience compared to classic multi-page applications, which require a full page refresh with each change.
The history of SPA dates back to 2002, when a technology similar to the modern version of SPA was described. However, it was not until 2006, when the AJAX mechanism appeared, that it became possible to create single-page applications. AJAX allows data to be sent asynchronously, without reloading the entire document, which is crucial for SPA to work. This allowed web applications to become more interactive and fast, revolutionizing the way we use the Internet.
A SPA application works by loading all resources (HTML, CSS, JavaScript) during the user’s first visit, usually as a single HTML file. Then, when the user performs subsequent actions, the page dynamically updates the relevant elements, while the rest of the page content remains unchanged. It can be difficult for Google’s robots to index dynamically loaded content, so it is necessary to adjust the application architecture accordingly for SEO. Server-side rendering (server side rendering) can significantly improve SEO support for SPA applications.
This type of approach minimizes the need to reload the page, as in the case of MPA (Multi Page Application) pages, each action requires a full page refresh, leading to higher latency. SPA eliminates this need, resulting in a smoother user experience during each interaction.
In a Multi Page Application (MPA), each sub-page is loaded separately, which leads to a full page reload and can increase loading times. In Single Page Applications, the user moves between different parts of the page without reloading the entire resource, which improves application performance. SPA development is great for applications that require dynamic content updates, such as project management systems, e-commerce, and social media. An example of an SPA application is Google Maps, which dynamically updates the map view to improve the user experience.
For sites of a more static nature, such as blogs, MPA may be a more optimal solution. AnSPA site works dynamically, while MPA sites rely on a traditional model that loads a new subpage each time a user performs an action.
SPAs offer outstanding responsiveness because the user doesn’t have to wait for a new page to fully load every time they perform an action. This provides a significant advantage over traditional websites, where each new request causes a full load of all the site’s resources. As a result, the SPA site runs quickly, which directly translates into a positive user experience. An example is Google Play Music, which, as an SPA application, allows convenient listening to music in the background.
Traditional web applications require a full page refresh with each interaction, which increases the load on the server. In the SPA model, the server only processes new data, which reduces the amount of information transferred and the load on the system. Creating SPAs allows efficient management of server resources, speeding up application performance.
Not having to reload the entire document enables faster response to user actions and a more responsive, dynamic interface. SPA applications are ideal for creating dynamic user interfaces that seamlessly adapt to real-time interactions, eliminating latency and improving the overall user experience.
One of the biggest challenges of creating SPAs is their poor SEO support. In traditional websites, each subpage has its own URL, which makes it easier for Google’s robots to index. In the case of SPAs, where page content is loaded dynamically, it is more difficult to get good SEO visibility in search results. The solution may be server-side rendering (SSR) or pre-rendering techniques, which improve the ability of search engines to index.
SPAs, due to the processing of most client-side activities, may be more vulnerable to XSS (cross-site scripting) attacks. Securing the application against such attacks and properly managing the application’s state on a single page is key to ensuring its security. What makes SPA different from other applications is that most of the activity takes place on a single, immutable page, which may require additional security.
A number of modern technologies and tools are used to create SPAs. JavaScript is at the forefront of the technologies used in SPAs, allowing dynamic content updates without reloading the page. Frameworks such as Angular, React.js and Vue.js are currently the most popular tools for developing SPA applications. These frameworks provide support for data binding, routing, and application state management, making it easy to create complex and interactive user interfaces.
In addition, tools such as Webpack and Babel help manage dependencies and transpile modern JavaScript into a format that most browsers can understand. Webpack enables modular code management, which is crucial in large projects, while Babel allows you to use the latest JavaScript features, even if they are not yet supported by all browsers. With these tools, SPA development becomes more efficient and enjoyable for developers.
WebAssembly (Wasm) opens up new possibilities for SPA application development. WebAssembly allows code to run close to native performance, which is especially important for compute-intensive applications such as graphics rendering tools and online games. SPA development using WebAssembly becomes more effective and efficient, as page resources can be processed faster and the application runs more like native applications.
Already, many companies are using WebAssembly to improve the performance of their applications. Here are some examples:
Autodesk: Fusion 360, a browser-based 3D design tool, uses WebAssembly to provide users with a native experience without installing software.
Figma: A web interface design tool uses Wasm to minimize latency and speed up rendering of graphics and interfaces.
As WebAssembly evolves, it can be expected to become the standard for building SPAs. Wasm is already proving itself in compute-intensive applications, but its popularity may increase in the future, affecting the daily workflow in many web projects. The WebAssembly System Interface (WASI) also opens the door to running Wasm applications outside the browser, which will bring SPA applications closer to operating more like native applications.
If your application requires dynamic data updates and seamless interaction, SPAs will be the best option. MPAs will work better for static pages that don’t require frequent content changes. It’s also worth considering whether older browsers will struggle to support advanced technologies such as WebAssembly, which SPA uses.
The SPA application is tailored to the needs of almost any company that expects a fast-acting, powerful digital product that is fully modern and multimedia. SPA is most often used for sites displaying news, acting as social media and handling very large amounts of data. By eliminating the need to reload the entire page, users can use the application intuitively and without delays.
Often these applications are also used by online stores. Every customer wants to quickly get acquainted with the site’s offerings, without a long wait, and this is what SPA provides. With dynamic user interfaces, online stores can offer a more interactive and engaging shopping experience. As a result, SPAs are becoming increasingly popular in various industries, from e-commerce to social media, providing smooth and fast web applications.
Single page applications such as Gmail, Slack and Trello perfectly illustrate how the use of SPAs can improve the speed and fluidity of an application. By eliminating the need to reload the page, users can use the application intuitively and without delays.
Single Page Application is an advanced model for building web applications that offers speed of operation and improved user experience. By eliminating the need to reload the entire page, SPAs are becoming increasingly popular for dynamic interfaces. Despite some challenges, such as SEO and security, the use of SPAs combined with modern technologies such as WebAssembly opens up new possibilities in building efficient web systems.
