Understanding The 3-tier Web Application Architecture on AWS and Building One in 5 minutes

Overview

In this article, we’ll explore the classic 3-tier web application architecture: what it is, why it remains relevant despite newer approaches like serverless and containers, when it makes the most sense to use, and who is using it today. Finally, we’ll show you how to launch your own 3-tier web app in just 5 minutes using an AI agent we’ve built. Try it here.

What is the 3-tier architecture?

A “3-tier web application” is a classic way of structuring applications so that each major function has its own dedicated layer:

• Presentation Tier – where users interact with the app.
• Application Tier – where business logic is executed.
• Database Tier – where data is kept safe.

This model has been around for decades because it’s simple, scalable, and reliable.

Why does it matter?

The 3-tier design separates responsibilities into clear layers, which makes applications:

• More secure – databases aren’t directly exposed to the internet.
• Scalable – each tier can scale independently based on demand.
• Maintainable – one layer can be updated without breaking the others.
• Resilient – load balancers and multiple instances help withstand failures.

When should you use it?

The 3-tier model is a great fit for:

• Business applications (CRMs, ERPs).
• E-commerce websites where both traffic spikes and data integrity are critical.
• Enterprise internal tools that need reliability and structured separation.
• Education & training projects where learners want to understand web hosting fundamentals.

Who uses it today?

Despite the rise of serverless and container-based models, many real-world systems still rely on 3-tier architecture, sometimes enhanced with modern tooling:

• Banks & financial institutions use it for secure transaction systems.
• Healthcare providers run patient record systems this way.
• Large enterprises (retail, airlines, universities) still host internal portals on it.
• E-commerce platforms often start with a 3-tier setup before evolving into microservices.

Chances are, if you’ve logged into a university portal, used a government service website, or shopped on an older e-commerce platform, you’ve interacted with a 3-tier application.

Is 3-tier architecture outdated?

In recent years, many companies have embraced serverless architectures (AWS API Gateway + Lambda + DynamoDB) or containerized solutions (ECS, EKS, Fargate, Kubernetes). These can scale faster, reduce management overhead, and cut costs for specific workloads.

But the 3-tier model is far from obsolete:

• Many legacy systems are built on it.
• New projects that need control, predictability, and compatibility with existing code still adopt it.
• Its simplicity makes it easier to teach, learn, and prototype with.

Advantages of 3-tier today

Even in 2025, 3-tier has clear benefits:

• Simplicity: easy for small teams to understand and implement.
• Compatibility: works with most languages, frameworks, and legacy code.
• Control: fine-tune performance and configuration per tier.
• Predictability: decades of proven patterns mean fewer surprises.

How to create a 3-tier web application in AWS?

In AWS, the 3-tier architecture can be recreated using cloud-native services that are secure, cost-efficient, and straightforward even for beginners. The application is divided into three layers, each with its own purpose:

1. Presentation Tier – AWS Application Load Balancer (ALB)
   • Acts as the entry point of your application.
   • Deployed in public subnets to receive traffic from the internet.
   • Distributes requests across multiple servers to keep your app reliable and scalable.
2. Application Tier – Amazon EC2 in private subnets
   • Runs the business logic of your application.
   • EC2 instances handle incoming requests, execute your code, and interact with the database.
   • Hosting them in private subnets enhances security by preventing direct internet access.
3. Database Tier – Amazon RDS in private subnets
   • Stores and manages your application data.
   • Provides automatic backups, scaling, and patching as a fully managed service.
   • Ensures your data remains secure, consistent, and highly available.

Additional supporting services can strengthen the architecture:

• Bastion Host (EC2 in a public subnet): allows secure administrative access to private servers.
• Amazon S3: offers durable object storage for static assets, images, or backups.

Hands-on walkthrough to launch your own 3-tier web app in 5 minutes

If you search online, you’ll find many tutorials about how to set up a 3-tier web app on AWS manually. They involve creating VPCs, configuring subnets, launching EC2s, attaching load balancers, provisioning RDS, and so on.

But there are associated challenges:

• Those tutorials are time-consuming to read and follow.
• Every step requires attention to detail, and even small mistakes can cause security or connectivity issues.
• Beginners often feel overwhelmed by the number of services and configurations involved.

This is where our AI-powered tool - The Backend agent for AWS - makes things so much simpler. With our AI-powered solution, you don’t need to spend hours following step-by-step guides. Instead:

1. Tell us about your goals.
2. The agent will determine the configurations required to achieve your goals.
3. The agent automatically creates a CloudFormation template customized for your selected setup. A CloudFormation template is a simple text file that defines all the AWS resources you want to create and manage together as a single unit, called a stack. Any resources deployed through this template can be managed, modified, or deleted just like those you configure manually in the AWS Console.
4. Deploy all services with the cloudformation template in one click. It covers the entire 3-tier architecture — including an Application Load Balancer in public subnets, EC2 instances in private subnets, and an RDS database safely tucked away in the data tier.

Whether you’re a beginner learning AWS or a team looking to save time on repetitive infrastructure work, our product makes building a 3-tier web application easier than ever.

Let’s see how to use the tool to set up a 3-tier web application in minutes.

1.After logging in, click Next.

2.Choose a region where you want to deploy your resources, and click Next.

3.There are five common use cases. You can select one or multiple of them depending on your needs. For a 3 tier web application, choose “I want to host a website or web application.”

4.You’ll be asked whether you want to provide a domain name to enable https configuration. If you select Yes, there will be some additional setup questions. In this demonstration, we will select “No” to proceed without HTTPS.

5.A summary page will show the resources that will be created, along with a detailed cost estimation breakdown. You can also make customizations to the services.

6.The agent will generate a CloudFormation template. A CloudFormation template is a text file written in JSON or YAML format that defines the AWS resources you want to provision and manage as a single unit, known as a "stack.” You can edit the script if needed. If you are not familiar, just leave it as-is. Click Next.

7.Provide a stack name. Click OK to continue.

8.Click on the link. This will open the CloudFormation Quick Create Stack page in your AWS account. If you have not yet, please login to AWS.

9.On the Quick Create Stack page, scroll down and click Create stack. If prompted to acknowledge that “AWS CloudFormation might create IAM resources with custom names,” check the box.

10.CloudFormation will now create all required resources. While it runs, you can return to the backend agent to view the “How to Get Started” instructions.

11.You can monitor the status of the resource creations under the CloudFormation Resources tab. Once they are all “CREATE_COMPLETE”, the services are all set up.

That’s it! You now have a fully functioning 3 tier architecture ready to use.

If you prefer, you can watch the video walkthrough here.

Wrapping Up

In this article, you learned what is the 3-tier web application architecture:

• Presentation Tier – where users interact with the app.
• Application Tier – where business logic is executed.
• Database Tier – where data is kept safe.

But setting up everything manually can be very time-consuming. That’s why we created the AI-powered Backend Agent for AWS. With just a few clicks, you can set up your infrastructure and skip directly to deploying your web application. It helps you avoid the complexity, while still giving you the flexibility to customize.

The Backend Agent for AWS is currently in beta and is free to use. Try out the agent here and don’t hesitate to share your experience with us. We can’t wait to see what you’ll build!