Although the first web applications appeared at the end of the 20th century, there is still no single classification of their types. This is due to the fact that the last 5-10 years their development has made a revolutionary leap, generating new varieties.
In general, all web applications can be divided into 5 types. The division is somewhat arbitrary, since it is possible to combine several types in one application.
- Server-based web apps
Web server applications work on remote computers. They are written using programming languages such as Python, Java, Ruby, PHP, C#, etc. They require almost no user intervention. Switching between pages causes the generation of new content, which is displayed on the client.
An example of a purely server-based application is push notifications (from email services, messengers, telecom operators) in smartphones. The client receives information that there is a new message, letter, changes in tariff, without taking any action.
- Client web-applications
Client applications in their pure form don’t require a server and make do with JavaScript capabilities, using the user’s browser as a shell. They do not persist beyond one session.
Typical examples of such applications are: simple games, browser-based photo editor.
- SPA applications
Single page application (SPA, single-page web applications) implement complex functionality within a single browser window without rebooting. Dynamic update of the page content is achieved by technology AJAX (Asynchronous JavaScript and XML). In response to the user’s actions (scrolling the page, clicking buttons, filling out a form, moving a slider, etc.) the content of the page will change.
An inexperienced user might even think that he is dealing with a desktop application, because all the changes are happening almost immediately. By the way, many mobile apps use this approach.
When combined with JavaScript frameworks (Angular, React, Vue), the operation of such programs becomes as smooth as possible.
Almost all email services are SPA.
- MPA applications
Multi Page Application (MPA, multi-page web applications) are used to build complex systems. In this case, any change in the data leads to a full page reload. When there is a large array of data and content, a variety of information presented, the MPA are best suited.
Despite the fact that they require large amounts of resources for implementation and significantly more expensive, other types of web applications cannot replace them. However, trends show that the overall share of MPAs is gradually decreasing.
A standard example of such an application is online stores with a large array of products (Amazon, Citilink, etc.).
- PWA applications
Progressive Web Application (PWA, progressive web applications) – a new way of “presenting” web services, which brings them as close as possible to the usual, familiar desktop application, but at a higher level.
Let’s imagine the situation: a person visits a certain site, which offers him to install it on other devices. Now both on the PC and on the phone you will be able to receive notifications and work offline, regardless of the device model and its power.
The main area of application of such applications is mobile devices. The user no longer needs to enter the AppStore or PlayMarket to download the program – the browser will do everything automatically (it will also create a shortcut on the desktop, allow to work with itself without access to the network, etc.). In fact, we get an analogue of the usual application with the same functionality and a lot of advantages (PWA does not require extra smartphone memory, for which you have to delete photos and videos, they weigh less than 1 MB).
When new content appears PWA sends a push-notification to the user. It should be recognized that in the near future, these applications can replace almost all mobile counterparts. Although the technology appeared in 2007 in Apple, initially it did not “go” because of the weak “progressiveness” of the public, but by the second half of 2016 Google has developed it and made it popular.
PWA-versions of apps are found in many companies (the same Aliexpress has almost doubled the conversion rate from new visitors thanks to it).