A Strong Foundation: An Introduction to the Tiers of Web Architecture

Raghav Bang
Published in
4 min readApr 21


Let's understand 1 Tier, 2 Tier, 3 Tier and n Tier Architecture.

Before starting let's understand few technical terms that will help us to understand Web Architecture in better way.

Tier: It's basically a layer in web architecture.

The three layers involved in a Web Architecture are commonly referred to as the Presentation Layer, Business Layer, and Data Layer. These layers are responsible for handling user interface-related tasks, application logic, and data storage and retrieval, respectively. By organizing an application into these distinct layers, developers can create a more modular, scalable, and maintainable system.

Presentation Layer: Also known as the user interface (UI) layer, is the layer in an application that is responsible for displaying information to the user and handling user input. It’s the part of the application that the user interacts with directly. It acts as a mediator between the user and the application’s underlying logic and data, allowing users to interact with the application without needing to understand the underlying complexities.

Example: Login/Signup Page

Business Layer: Also known as the Application Layer, is the layer in an application that contains the logic and rules that govern the behavior of the system. It acts as a bridge between the Presentation Layer and the Data Layer, transforming user input into actions that the system can perform and generating output for display.

Example: Adding items to the cart, calculating the total cost of the items, and applying any discounts or promotions.

Data Layer: Also known as the Persistence Layer, is the layer in an application that is responsible for storing and retrieving data. It is the part of the application that interacts with databases, file systems, or other storage systems to persist data between application sessions.

Example: Insert, Update, Delete Operation on Database

Let’s take a look at the different tiers in web architecture.

1 Tier Architecture

A one-tier architecture, also known as a monolithic architecture, is a type of software architecture in which all the layers of an application are combined into a single executable unit. This means that the Presentation Layer, Business Layer, and Data Layer are all bundled together in a single application making it simple and easy to develop and deploy.

However, this approach can also make the application less scalable, less flexible, and harder to maintain as it grows larger and more complex.

A common example of a one-tier architecture is a desktop application, where the user interface, application logic, and data storage are all contained within a single executable file.

2 Tier Architecture

It is also known as a client-server architecture, is a type of software architecture that separates the application into two main tiers or layers: the Presentation Layer and the Data Layer.

The Client-Application server communicates directly with the Database server. The Client-Application is responsible for both interfacing with the user and saving data in the database server. It sends requests to the server, which processes the requests and sends back the requested data. In other words, the Client-Application combines the Presentation Layer and the Business Layer.

An example of a two-tier architecture is a client-server application, where the Presentation Layer is the client program running on the user’s machine, and the Data Layer is the server program running on a remote machine or in the cloud.

3 Tier Architecture

It is a modular client-server architecture that consists of a Presentation (client) layer, an Application/Business Logic layer, and a Data layer. In this architecture, there is a clear separation of concerns between the different layers. This modular approach allows for greater flexibility and scalability, as changes can be made to one layer without requiring changes to the entire application.

It scales horizontally well due to the distributed deployment of application servers. Maintenance is simplified because each layer is treated as an independent entity. But with this architecture complexity also increases.

N-Tier Architecture

The N-tier architecture is similar to the three-tier architecture, but with an increased number of application servers, each represented as an individual tier. This allows for the distribution of business logic across multiple tiers, resulting in improved performance and scalability. By separating the business logic into multiple tiers, the application can better handle large volumes of data and traffic, and can more easily adapt to changing requirements or conditions.

For example, in a four-tier architecture, the first tier is the user interface or presentation layer, the second tier is the application server, the third tier is the database server, and the fourth tier is an additional server that handles specific business logic.

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