Magento architecture from different perspectives
Depending upon your role and purpose for learning more about Magento, there are several different ways to view the Magento architecture. For example, a developer who wants to create new modules or perhaps customize an existing module will want to understand the architecture of a module itself, and how it fits into the larger view, with the Magento framework and other components. However, a merchant who wants to quickly build an online storefront wants to view the collection of components from a higher level, and understand the components that impact the look, feel, and user interaction components.
Architecture layers diagram
The following diagram illustrates the components and shows the “layers” or tiers in Magento.