At first glance it may seem that there’s no difference at all. Both websites and web applications run in browsers, both require access to the internet, both have a front end and a back end written in the same programming languages.
There are several points that draw a line between a website and a web application.
The first point to start ‘web application vs. website’ differentiation with is interaction.
Website: A website provides visual and text content that the user can see and read, but not affect in any way.
Web Application: In web application, the user can not only read the page content but also manipulate the data on this page. The interaction takes the form of a dialog: the user clicks a button or submits a form and gets a response from the page. This response may take a form of a document download, online chat, electronic payment and more. An illustrative example of a web application interactivity is an online banking application that performs transactions based on a customer’s input. Similar functionality can be found in an online store that allows visitors to search through the catalog and buy items instantly. Social networks are another impressive example. They connect users via chats and blog platforms, generate feed content based on users’ preferences and allow for almost unlimited content sharing, not to speak of their built-in mini-applications for user entertainment.
Authentication is the procedure that involves entering a user’s login and password to get access to the system. User accounts must be secured to prevent unauthorized access and leakage of sensitive data.
Website: Authentication is not obligatory for informational websites. The user may be offered to register to get access to additional options unavailable to unregistered website visitors. For example, you may look through news and featured articles on a news website without bothering to register. However, if you want to leave a comment you will have to log in. This way, users confirm their identity allowing the system to block spammers.
Web Application: Web applications mostly require authentication, as they offer a much broader scope of options than websites. Consider an example of social networks. When you register, you create an account and get a unique identification number. The system warns you if your login and password are weak. If you leave them unchanged, hackers may reach your account and steal your information, as well as irritate other users with junk emails under your name.
As you can see, both websites and web applications may require authentication. However, for web applications, it is obligatory due to security reasons.