In computing, a web application or web app is a client-server software application in which the client (or user interface) runs in a web browser.
Web applications are popular due to the ubiquity of web browsers, and the convenience of using a web browser as a client to update and maintain web applications without distributing and installing software on potentially thousands of client computers is a key reason for their popularity, as is the inherent support for cross-platform compatibility. Common web applications include webmail, online retail sales,online auctions, wikis and many other functions.
An emerging strategy for application software companies is to provide web access to software previously distributed as local applications. Depending on the type of application, it may require the development of an entirely different browser-based interface, or merely adapting an existing application to use different presentation technology. These programs allow the user to pay a monthly or yearly fee for use of a software application without having to install it on a local hard drive. A company which follows this strategy is known as an application service provider (ASP), and ASPs are currently receiving much attention in the software industry.
Security breaches on these kinds of applications are a major concern because it can involve both enterprise information and private customer data. Protecting these assets is an important part of any web application and there are some key operational areas that must be included in the development process.This includes processes for authentication, authorization, asset handling, input, and logging and auditing. Building security into the applications from the beginning can be more effective and less disruptive in the long run.
In cloud computing model web applications are software as a service (SaaS). There are business applications provided as SaaS for enterprises for fixed or usage dependent fee. Other web applications are offered free of charge, often generating income from advertisements shown in web application interface.
Many businesses are enabled by open source web applications such as e-commerce software that facilitates easily creating an online retail store. Most businesses today do not need to buy data center hardware such as servers because they are affordably rented on a short term basis from a plethora of hosting companies that provide turnkey implementations of web applications. It is common for hosting providers to also offer packages of hardware and all necessary software to support the business needs of a company. Innovations in all aspects of web applications are providing tremendous economic value by increasing competition by reducing barriers to entry for new companies.