Standalone models

Most small or ad hoc web applications at some point or another were hosted on a physical or virtual server and within a single monolithic installation, and this is commonly encountered in simpler self-hosted applications such as a small or medium business web page, inventory service, ticketing systems, and so on. As these applications or their associated databases grow, it becomes necessary to separate the components or modules to better support the scale and integrate with adjacent applications and data stores.

These applications tend to use commonly available turnkey web frameworks such as Drupal, WordPress, Joomla!, Django, or a multitude of other frameworks, each of which includes a content delivery manager and language platform (for example Java, PHP: Hypertext Pre-Processor (PHP), Active Server Pages (ASP.NET), and so on), generated content in Hyper Text Markup Language (HTML), and a database type or types they support (various Server Query Languages (SQLs), Oracle, IBM DB2, or even flat files and Microsoft Access databases). Available as a single image or install medium, all functions reside within the same operating system and memory space. The platform and database combinations selected for this model are often more a question of developer competencies and preferences than anything else. Social engineering and open source information gathering on the responsible teams will certainly assist in characterizing the architecture of the web application. 

A simple single-tier or standalone architecture is shown here in the following figure: