Web Application Architecture: The Latest Guide

When a user logs on to a desktop/laptop or a mobile, opens a browser, and types the name of a website, the browser displays the required information and the user performs an action on the site. Have you ever wondered how computers retrieve this information and what happens in the background? It’s an underlying web application architecture that makes this process possible. In this article, you’ll discover what a web app architecture is, how a web application architecture diagram looks, and how you can design the right architecture for web apps.

An Overview of Web Application Architecture

A web app architecture presents a layout with all the software components (such as databases, applications and middleware) and how they interact with each other.  It defines how the data is delivered through HTTP and ensures that the client-side server and the backend server can understand. Moreover, it also secures that valid data is present in all user requests. It creates and manages records while providing permission-based access and authentication.  Choosing the right design defines your company growth, reliability and interoperability and future IT needs. As such, it is important to understand the components comprising the architecture of web apps.

Web Application Architecture Components

Typically a web-based application architecture comprises of three core components: 

1) Web Browser: The browser or the client-side component or the front-end component is the key component that interacts with the user, receives the input, and manages the presentation logic while controlling user interactions with the application. User inputs are validated as well, if required. 

2) Web Server: The web server also known as the backend component or the server-side component handles the business logic and processes the user requests by routing the requests to the right component and managing the entire application operations. It can run and oversee requests from a wide variety of clients.

3) Database Server: The database server provides the required data for the application. It handles data-related tasks. In a multi-tiered architecture, database servers can manage business logic with the help of stored procedures.

What Is a 3-Tier Architecture?

In a traditional 2-tier architecture, there are two components namely the client side system or the user interface and a backend system which is usually a database server. Here the business logic is incorporated into the user interface or the database server. The downside of 2-tier architecture is that with an increased number of users, the performance decreases. Moreover, the direct interaction of the database and the user device also raises some security concerns. Railway reservation systems and content management systems are a couple of applications that are usually built using this architecture. 

When it comes to 3-tier architecture, there are three layers:

1. Presentation layer/Client layer
2. Application layer/Business layer
3. Data layer

In this model, the intermediate servers receive client requests and process them by coordinating with subordinate servers applying the business logic. The communication between the client and the database is managed by the intermediate application layer thereby enabling clients to access data from different DBMS solutions. 

The 3-tier architecture is more secure as the client does not directly access the data. The ability to deploy application servers on multiple machines provides higher scalability, better performance, and better re-use. You can scale it horizontally by scaling each item independently. You can abstract the core business from the database server to efficiently perform load balancing. Data integrity is improved as all data goes through the application server which decides how data should be accessed and by whom. For that reason, a change of management is easy and cost-effective. The client layer can be a thin-client which means hardware costs are reduced. This modular model allows you to modify a single tier without affecting the remaining components. 

Layers of Modern Web Application Architecture

Building a layered modern web app architecture helps you to identify the role of each component of an application and easily make changes to the corresponding layer without affecting the overall application. It enables you to easily write, debug, manage and re-use code. 

The three layers of a web app architecture:

1. Presentation layer/Client layer 
2. Application layer/Business logic layer 
3. Data layer

Here is an extra web application architecture diagram of layers for you:

Application Layer: Web Server

What is a web server? Simply put, a web server runs one or more websites or web apps. The web server uses HyperText Transfer Protocol (HTTP) along with other protocols to listen to user requests via a browser. It processes them by applying business logic and delivering the requested content to the end-user. 

A web server can be a hardware device or a software program. 

• Hardware Web Server: A computer device that is connected to the internet and contains web server software and web app components such as images, HTML docs, JS files and CSS style sheets. 
• Software Web Server: This is software that understands URLs and HTTP protocols. Users can access it via domain names to receive the requested content. 

While a static web server delivers the content as it is to the browser, a dynamic web server updates data before delivering it to the browser. 

Apache is a popular open-source web server from Apache Software Foundation. It was developed by Robert McCool in C and XML in 1995. Apache is based on a process-driven model wherein every request results in the creation of a new thread. The modular design of Apache allows you to easily scale individual resources. With minimal configuration you can manage even a large traffic. It works on MacOS, Windows, and Linux environments. However, Linux is the most preferred environment for Apache.

While it uses a file-system to process static content, dynamic content is processed within the server. Using .htaccess files, you can perform additional configurations to the server settings.  Security is good. It offers support via IRC, Stack Overflow and mailing lists.

NGINX is another popular web server that is usually pronounced as "Engine X." Developed by Igor Sysoev in 2004, NGINX quickly became popular. It operates on an event-driven model wherein thousands of requests are processed within a single thread, delivering more with minimal resources. It uses PHP to serve static resources and serves static content 2.5 times faster than Apache. Dynamic content is served via external processes. When it comes to interpreting requests, Apache passes the file system location while NGINX passes the URI. This feature extends the NGINX capability as a load balancer, HTTP Cache and a proxy server.  

While it supports Unix-based OS, Windows compatibility is limited. You can’t make additional configurations. The smaller codebase offers better security. Dynamic modules are not supported. Along with mailing lists and IRC, Forum is available too. 

NGINX has an edge over Apache as it serves as a web server as well as a proxy server. The event-driven approach that processes thousands of requests in a single thread offers greater performance, speed and cost-effectiveness. 

Presentation Layer: Client-Side Component (Front-End)

The client-side component of a web application architecture enables users to interact with the server and the backend service via a browser. The code resides in the browser, receives requests and presents the user with the required information. This is where UI/UX design, dashboards, notifications, configurational settings, layout and interactive elements come into the picture. 

Here are some of the most commonly used front-end technologies:

HTML

HTML or Hypertext Markup Language is a popular standard markup language that enables developers to structure web page contents using a series of page elements. Developed by Tim Berners-Lee and released in 1993, HTML quickly evolved and became the standard markup language across the globe.

CSS

CSS or Cascading Style Sheets is a popular style sheet language that enables developers to separate website content and layout for sites developed using markup languages. Using CSS, you can define a style for elements and reuse them multiple times. Similarly, you can apply one style across multiple sites. It is simple and easy to learn.  You can apply a style for a single element, an entire webpage or the entire website. It is device-friendly too.

Browser compatibility and security are two areas that raise a concern. Similarly, different versions of CSS also create confusion. It is advised for developers to  check the compatibility before making any changes to the design. 

JavaScript

JavaScript or JS is the most popular client-side programming language which is used by more than 90% of websites in recent times. It was designed by Brendan Eich of Netscape in 1995. JavaScript uses a simple, easy-to-learn syntax. The language is so popular that every browser comes with a JS engine to run JavaScript code on devices. It is easy to insert JS code on any web page which makes it highly interoperable. It allows you to create rich interfaces to deliver a better UI/UX experience. Being on the client-side, JS reduces the server load as well. 

However, developers should be careful about the security as the code is executed on the client-side which can be exploited by hackers at times.

React

React is an open-source JavaScript that gained popularity in recent years. It was developed by Jordan Walke of Facebook in 2013. React benefits include enabling developers to easily create high-quality dynamic web applications with minimal code and effort. 

ReactJS is easy to learn and use. There is extensive documentation and plenty of handy tools available for developers. The code is reusable. ReactJS uses a virtual DOM which means concerned elements are updated when a change is made instead of the entire DOM tree being rewritten. It improves efficiency and optimizes memory usage. ReactJS uses a one-way Data flow which means changes made to the “child” elements do not affect the “parent” element. The code is easy to test and SEO-friendly. 

On the downside, the ReactJS development environment is highly dynamic which means developers should proactively monitor the changes and quickly adapt new skills to leverage React. Moreover, React technologies are improving rapidly, however, the documentation is unable to catch up with this pace. A critical area of concern is that ReactJS focuses on the UI part and you need to depend on other libraries for client-side functionalities.

Vue.js

Vue.js is an open-source JavaScript framework written by Evan You in 2014. This framework enables developers to easily build UI interfaces for web, desktop and mobile devices. Vue.js comes with handy tools that serve basic programming needs. The tool is lightweight for downloads and installation. It is easy to learn and use. It uses a virtual DOM so that when a user interacts with an element, the browser does not have to render the entire page, only the element. The speed and performance is good. It uses a two-way data binding model allowing you to track data and update related components more efficiently. The components are reusable. It easily integrates with existing apps. The documentation is concise and well-structured. Community support is good. 

While the community support is good, Vue.js is largely adapted by Chinese companies such as Alibaba and Xiomi. As such, forums and discussions are often done in Chinese language, creating a language barrier for English speaking people. The tool kit suits basic projects but offers limited support for large scale projects. The flexibility that it offers can pose quality issues on large projects as well. GitLab, Alibaba and Adobe are some of the popular companies that use Vue.js.

Angular.js

Angular is an open-source web app framework developed by Google in 2016. It is a complete rewrite of the Angular.js framework. As of now, it is one of the most popular front-end development frameworks available in the market.

NGModules is the building block of Angular, offering all functionalities for developing applications such as components, modules, templates, directives, service and dependency injections, routing etc.  It helps developers quickly build prototypes. It uses plain HTML templates. Testing is quick and easy owing to the dependency injection architecture style.

Angular uses two-way data binding which makes DOM manipulations easy and quick. The CPU-performance enhancing features make it a good choice for large-scale apps. It comes with various plugins, tools out-of-the-box. Coming from the IT giant Google, Angular enjoys a vibrant community support. The popularity and market value imply that you’ll find highly skilled Angular professionals in the market. 

However, the hierarchical structure can sometimes make debugging a challenge. Concepts such as Inversion Of Control, Dependency Lookup and Dependency Injection require a steep learning curve. You need JavaScript installed on the machine to run Angular. While Two-way data binding is a great feature, it can result in slow performance on older and legacy devices. Integrating legacy infrastructure with Angular is a concern too.

If you want to pick the best ones out of these front-end development tools, React and Vue.js are highly recommended. React is a lightweight tool that comes with the best developer functions, enabling you to quickly build quality software. 

Vue.js is a view-oriented product that is lightweight, easy to use and comes with a powerful set of developer tools. To get started, you just need to simply load the interface and add JavaScript. 

Application Layer: Server-Side Component (Back-End)

The server-side component is the key component of the web application architecture that receives user requests, performs business logic, and delivers the required data to the front-end systems. It contains servers, databases, web services etc.

Here are some of the most commonly used server-side technologies:

Node.js

Node.js is an open-source cross-platform runtime environment developed by Ryan Dahl. It was built on Google Chrome V8 Engine to run network and server-side applications and was released in 2009. Developers use JavaScript to build node.js applications and run them on node.js runtime using Windows, macOS, and Linux platforms. 

Node.js is highly popular as it offers a rich library of JavaScript modules that enable developers to quickly build quality applications. Node.js doesn’t buffer data and executes code super fast. It is event-driven and asynchronous and runs on a single thread while being highly scalable. Node.js best suits apps that are data streaming, data-intensive, I/O bound, and JSON-API based. Paypal, Uber, eBay, and GoDaddy are some of the popular applications that are powered by Node.js. It doesn’t suit apps that are CPU-intensive.

Java

Java is one of the most popular and effective programming languages of all time. Written by James Gosling in 1995, Java is an object-oriented and class-based programming language that enables developers to write code and run it on any platform using Java virtual machine (JVM) environment. It means you don’t need Java on the target machine. The language is easy to learn, code, compile, and debug. Being platform-agnostic, Java programs are cost-effective to build and run. Leveraging OOPS concepts, you can reuse objects in other programs. As it doesn’t work with explicit pointers, unauthorized memory access is avoided. It supports multi-threading, portability, automatic garbage collection, distributed networking, and so on. 

On the downside, Java requires significant memory space. Owing to the JVM abstraction, the programs run slower as well. There is no backup either. The UX/UI is not attractive. However, for developing server-side components of the web application architecture in Java, the benefits outweigh the drawbacks.

Python

Python is an open-source high-level programming language written by Guido Van Rossum and released in 1991. Today, it is a fast-growing and popular programming language and a strong alternative for building web app architecture in Java. It is simple to learn and develop and rich in features. This dynamically-typed language is highly flexible and suitable for small and large web application projects as well as a variety of segments such as mobile apps, video games, AI programming, and so on. It allows you to do more with less code which means you can quickly build and test prototypes that increases productivity. Python offers an extensive library that contains code for almost every type of program. With its vibrant community, support is always available. 

However, compared with modern languages, Python is slower. Threading issues are another concern. Python is not native for mobile apps. Google, Spotify, Instagram, and Facebook are some of the popular IT giants that use Python.  

PHP Laravel

PHP Laravel is a PHP framework that helps developers to build custom web apps with ease. It is an open-source framework that is quite popular among other PHP frameworks. PHP Laravel is a MVC (Model, View, and Controller)-based framework. 

Laravel syntax is elegant and expressive. With extensive built-in functions and structures, developers can easily write code and deploy apps faster. It improves performance and speed. Documentation is good. An important advantage of PHP Laravel is its automated testing feature that helps you to test and debug errors in the initial stage. Automatic tasks and scheduling is available too. Object Relational Mapping support is elegant. PHP Laravel offers cross-site request forgery tokens that offer security. It is scalable and cost-effective.

However, product upgrades can create problems at times. The Laravel Composer can be improved. Since it’s a relatively new product, community support is not so great. PHP Laravel best suits medium and small organizations.

Go

The Go programming language comes from the IT giant Google, which gives it considerable strength. It was written by Robert Griesemer, Ken Thompson and Rob Pike in 2009. Go is also known as Golang. It is similar to the C language and is easy to learn and build. As there are no virtual runtimes, Go code compiles faster and produces smaller binary as well. It uses static typing and interface types. The standard library offers a range of built-in functions along with testing support. Garbage collection is available. Concurrent programming is easy compared to other languages.

On the downside, the library support is not adequate. The community support is not receptive on some occasions. Implicit interfaces can be challenging to manage. Without generics, reuse of code is not easy.

.NET

.NET is a software development framework developed by Microsoft and released in 2001 for desktop and web applications. Coming from the IT giant Microsoft,. NET quickly became popular for developing a variety of software products. 

.NET comes in three flavors:

•  .NET Framework: It is the first product that was specific for the Windows platform.
• .NET Core: The .NET Core was released in 2016 as a cross-platform solution to accommodate macOS and Linux platforms. 
• Xamarin: Xamarin is not developed by Microsoft but was acquired by the company in 2016. Xamarin extends the .NET platform to support native mobile application development.

.NET Standard is a single base class library for .NET Framework, .NET Core and Xamarin implementations. 

.NET is an Object Oriented Programming (OOP) model and uses a modular structure which enables developers to break down code into smaller pieces and seamlessly build and manage software products using CI/CD pipelines. It offers a robust and yet simple caching system that improves speed and performance. Automatic monitoring in ASP.NET is an added advantage. The Visual Studio IDE is a single IDE that helps developers to monitor and manage entire development operations from a single pane. Being language-agnostic and platform-agnostic, it allows you to use a variety of development environments. Deployment and management of code is flexible and easy. .NET comes with extensive documentation and community support.

However, object relational support is limited. Memory leaks are a concern that needs careful attention while coding apps. Being heavily dependent on Microsoft results in vendor lock-in and higher licensing costs. .NET best suits enterprise products that require high scalability and cross-platform solutions.

Ruby

Ruby is a popular programming language developed by Yukihiro Matsumoto of Japan in 1995. Time efficiency is one of the biggest advantages of Ruby. Combined with Rails framework, it allows developers to quickly build and deploy apps. The tool offers an extensive library and helpful tools. It comes with built-in security to mitigate risks related to SQL Injections, Cross-site Scripting Software (XSS), and Cross-site Request Forgery (CSRF). Ruby has a supportive community and good documentation.

While developers can quickly build applications, the speed of the applications is a concern. That said, this problem mainly affects large scale apps. Small and medium sized organizations don’t have any issues in this field.

Ruby is not as popular as Java or Python. For this reason, it is not easy to find quality professionals for this segment. Airbnb, GitHub, Bloomberg, and Etsy are a few popular companies that use Ruby.

Among the server-side development tools, Node.js and Python are highly recommended. Node.js is an easy to learn, lightweight, developer-friendly, highly scalable and extensible cross-platform solution. Python uses simple syntax, focuses on natural language and makes it easy to write and execute code faster. The community is also very supportive.

Application Layer: Application Programming Interface (API)

Application Programming Interface (API) is not a technology — it’s a concept that enables developers to access certain data and functions of a software. Simply put, it is a mediator that allows apps to communicate with each other. It comprises protocols, tools and subroutine definitions required to build apps. 

For instance, when you sign in to an application, the app calls the API to retrieve your account details and credentials. The application will contact the corresponding servers to receive this information and return this data to the user app. A web API is an API available over the web via HTTP protocol. It can be built using technologies such as .NET and Java. 

With APIs, developers don’t have to create everything from scratch but use existing functions exposed as an API to increase productivity and gain faster time to market. By reducing development efforts, APIs significantly reduce development costs. It also improves collaboration and connectivity across the ecosystem while enhancing customer experience.

There are different types of APIs:

• RESTful API: Representational State Transfer API in lightweight JSON format. It is highly scalable, dependable and delivers fast performance making it the most popular API.
• SOAP: Simple Object Access Protocol uses XML for data transmission. It requires more bandwidth and advanced security.
• XML-RPC: Extensible Markup Language – Remote Procedure Calls uses specific XML format for data transmission.
• JSON-RPC: Uses JSON format for data transmission.

Application Layer: Server Instance/Cloud Instance

Servers or cloud instances are an important part of a web application architecture. A cloud instance is a virtual server instance that is built, delivered and hosted using a public or a private cloud and accessible over the Internet. It works as a physical server that can seamlessly move across multiple devices or deploy multiple instances on a single server. As such, it is highly dynamic, scalable, and cost-effective. You can automatically replace servers without application downtime. Using cloud instances, you can easily deploy and manage web applications in any environment.

Data Layer: Database

A database is a key component of a web application that stores and manages information for a web app. Using a function, you can search, filter, and sort information based on user request and present the required info to the end user. They allow role-based access to maintain data integrity. 

While choosing a database for your architecture of web app, the size, speed, scalability, and structure are the four aspects that require your consideration. For structured data, SQL-based databases are a good choice. They suit financial apps in which data integrity is a key requirement.

To handle unstructured data, NoSQL is a good option. It suits apps wherein the nature of incoming data is not predictable. Key Value databases associate each value with a key and suit databases that store user profiles, reviews, blog comments, and so on. For analytics, Wide Column databases are a good choice.

Advanced and Scalable Web Application Architecture

The web app architecture is evolving. As such, organizations should proactively monitor these changes and realign the architecture accordingly. Here are few trends to check out:

Caching System

Caching system is a local data store that facilitates quick access to data for an application server instead of contacting the database every time. In a traditional setup, data is stored in a database. When a user makes a request, the app server requests that data from the database and presents it to the user. When the same data is requested again, the server should perform the same process again that is repetitive and time consuming. By storing this information in a temporary cache memory, apps can quickly present data to users. 

Caching system can be designed in four models:

• Application Server Cache: In-memory cache alongside the application server (for apps that have a single node)
• Global Cache: All the nodes access a single cache space.
• Distributed Cache: Cache is distributed across nodes wherein consistent hashing function is used to route the request to the required data.
• Content Delivery Network (CDN): Used to deliver large amounts of static data.

Caching Tools

Redis and Memcached are the two most popular caching systems with similar features. However, Redis offers a rich set of tools making it applicable for performing a variety of tasks. On the other hand, Memcached is simple and easy to use. 

The Caching system from AWS is called AWS ElastiCache. This web service enables administrators to scale and manage in-memory data store service in the cloud. AWS also offers a fully-managed Redis-compatible in-memory data store called the Amazon ElastiCache for Redis and a fully-managed Memcached-compatible in-memory data store service called the Amazon ElastiCache for Memcached. 

Cloud Storage (Amazon S3)

In a web application architecture, cloud storage is an obvious requirement. Cloud storage is about storing the data in the cloud and accessing it over the Internet. A cloud service provider provides the storage infrastructure on a pay-per-use subscription model. 

 As AWS is the most popular cloud service provider, Amazon S3 is the popularly used cloud storage solution in web application architecture AWS environments across the globe. Amazon Simple Storage Service (S3) is a cloud storage service that is flexible, cost-effective, durable, secure, and offers high availability and high scalability. 

In AWS, a cloud storage unit is called a “bucket” in which objects are stored. When a bucket is created, it is deployed in the region specified by the user. Once the deployment is done and objects are added to the bucket, the user can choose the storage class type along with features such as versioning control, lifecycle policies, bucket policy, and so on. AWS takes care of the lifecycle management for a group of objects including IAM policy and data protection. 

Azure Cloud Storage is another popular cloud storage service offered by Microsoft Azure. The best thing about Azure storage is the high availability of 99.95% uptime and high security. With the price of $0.18 per GB/month, it is highly cost-effective. Azure comes with a comprehensive stack of administrative access and developer tools that helps organizations to seamlessly coordinate across entire business operations.

Google Cloud Storage is a cloud storage offering from Google with a price tag of $0.02 per GB per month. It is available in multiple regions, offers high durability and easily integrates with other Google services. The tool comes with good documentation.

CDN (CloudFront)

A Content Delivery Network (CDN) is a server network that is installed in various geolocations to deliver content faster and better to users. Instead of contacting the central server, the users’ request is routed to a CDN server that stores a cached version of the content. As such, site speed and performance is increased and packet loss is decreased. The server load is decreased. It also enables segmentation of the audience and advanced web security. 

CloudFront is a popular CDN service for web application architecture aws. It acts as a distributed cache to deliver higher speed, low latency and better customer experience. Considering the global presence of AWS, CloudFront gives a wider range of geo locations for users. CloudFront integrates well with other AWS services such as Amazon EC2, AWS Lambda, Amazon CloudWatch, Amazon S3, and so on to make your job easier. It is flexible, easy to set up, and offers high scalability. It also features Elastic services and analytics. You can control access to the content as well.

Azure CDN is a popular content delivery network from Microsoft Azure cloud platform that  is easy to configure and use and offers low latency. 

Google’s content delivery network is called Cloud CDN. It leverages the globally distributed edge servers to cache content at the usage location to deliver content at high speeds.

CloudFlare is another popular CDN service. Though CloudFlare primarily offers robust DNS services and is not a traditional content delivery network, it acts as a reverse proxy to route traffic through its global network of data centers.

Load Balancer

As the name says, a load balancer is a service that balances traffic loads by distributing them across different servers based on the availability or predefined policies. When a user request is received in the load balancer, it retrieves the health of the server in terms of availability and scalability and routes the request to the best server. A load balancer can be a hardware component or a software program. 

Load balancing can be done in two ways:

1) TCP/IP level Load Balancing: Load balancing based on the DNS

2) App-level Load Balancing: Load balancing based on application load

Load Balancer Tools

The original elastic load balancer in AWS is AWS Classic Load Balancer. It works in the TCP layer (Layer 4) and the Application Layer (Layer 7). However, it forwards traffic only on one port per instance.

Another great LB is AWS Application Load Balancer works at the Application Layer (HTTP) and can forward traffic on multiple ports per instance. It also serves multiple domain names.

Multiple Servers 

In a traditional web architecture, you’ll see a web server and a database. The web server listens to client requests and contacts the database to provide the required information or process the business logic. When concurrent users increase, the web server will run out of resources. Even though upgrading the server configuration helps for a while, it provides limited capabilities while causing a single point of failure too. Deploying multiple servers is a good choice to create a highly scalable web architecture.

While designing the multi-server architecture, organizations can either connect multiple OS deployment servers to a single database or multiple databases. However, it is important to keep them replicated with appropriate content. Replication can be scheduled at specified times.

Message Queues

A message queue is a buffer that stores messages asynchronously and facilitates communication between different services in a web application. In today’s microservices environment, software is developed in smaller, modular, and independent building blocks that communicate with each other using RESTful APIs. Communication between these blocks is coordinated using message queues. Software components connect to the ends of these message queues to send and receive messages and process them. Message queues provide granular scalability, simplify decoupling processes, and increase reliability and performance. 

Amazon Simple Queue Service (SQS) is a fully managed publish/subscribe (pub/sub) messaging queue service offered by Amazon. Using the web services API provided by AWS SQS, users can access the messages via any programming language. Messaging is processed asynchronously which means messages wait in a queue and apps can access them at a later time. 

Amazon SQS uses two types of queues:

1. First-in First-Out (FIFO): The message strings are processed in the same order sent. It is useful for operations wherein the order of process is critical.

2. Standard Queues: The message string remains the same but the order might change. It is useful for tasks wherein messages are distributed to various nodes. 

AWS SQS supports 300 messages per second. Each message can be customized. You can retain messages for extended periods between 1 minute and 14 days. The ability to decouple app components helps to achieve high-performance. It eliminates administrative overhead while keeping data sensitive. The compatibility with other AWS products helps you to integrate it with existing infrastructure easily. 

Web Application Architecture Diagram

Here you will be able to analyze the process from start to end with the help of a web application architecture diagram. It is important to consider the elements and resources that would take action on the flow, such as the API, cloud storage, technologies, and databases.

Types of Web Application Architectures

The architecture of web applications can be classified into different categories based on the software development and deployment patterns.

Monolithic Architecture

A monolithic architecture is a traditional software development model — also known as web development architecture — wherein the entire software is developed as a single piece of code going through the traditional waterfall model. It means all the components are interdependent and interconnected and every component is required to run the application. To change or update a specific feature, you need to change the entire code to be rewritten and compiled. 

As monolithic architecture treats the entire code as a single program, building a new project, applying frameworks, scripts, templates, and testing it becomes simple and easy. Deployment is easy as well. However, as the code grows bigger, it becomes difficult to manage or make updates; for even a small change, you need to go through the entire process of your web development architecture. As each element is interdependent, it is not easy to scale the application. Moreover, it is not reliable as a single point of failure can bring down the application.

When you want to build a lightweight application and when you are on a tight budget, monolithic architecture will serve the purpose. However, it makes sense to use a monolithic model when your development team is working from a single location and not spread remotely.

Microservices Architecture

Microservices architecture solves several challenges that are encountered in a monolithic environment. In a microservice architecture, the code is developed as loosely-coupled, independent services that communicate via RESTful APIs. Each microservice contains its own database and operates a specific business logic which means you can develop and deploy independent services with ease. 

Since it’s loosely coupled, microservice architecture provides the flexibility to update/modify and scale independent services. Development becomes easy and efficient and continuous delivery is enabled. Developers can quickly adapt to innovation. For highly scalable and complex applications, microservices is a good choice.

However, deploying multiple services with runtime instances is a challenge. When the number of services grows, the complexity in managing them grows too. Moreover, microservices apps share partition databases. It means that you should ensure consistency across multiple databases that are affected by the transaction.

Containers

Container technology is the best option when it comes to deploying microservices. A container is an encapsulation of a lightweight runtime environment for an application that can run on a physical or a virtual machine. As such, applications run in a consistent environment right from the developer’s device to the production environment. By abstracting execution at the OS-level, containerization allows you to run multiple containers inside a single OS instance. While it reduces overhead and processing power, it increases the efficiency as well.

Containerization enables developers to add multiple app components in a single VM environment instead of segregating code into different VMs and thereby gain more application processing power. With its lightweight nature, containers run quicker. They are flexible, reliable, and best suited to policy-based microservices environments.

Docker is the most popular containerization technology that offers a comprehensive ecosystem for containerization technologies. It offers greater performance, easy-to-use technology, and large community support.

Serverless Architecture

Serverless architecture is a model of developing software applications. In this structure the provisioning of the underlying infrastructure is managed by an infrastructure service provider. It means you only pay for the infrastructure when it’s in use and not for the idle CPU time or unused space. Serverless computing lowers costs as resources are only used when the application is in execution. The scaling tasks are handled by the cloud provider. Moreover, back-end code gets simplified. It reduces development efforts, costs, and brings faster time to market. 

Multimedia processing, live streaming, chat bots CI Pipelines, IoT sensor messages, and so on are some of the use cases for serverless computing.

In a microservices architecture, you can perform serverless computing using AWS Lambda, API Gateway and API Step Functions. 

AWS Lambda

AWS Lambda is a serverless computing service offered by Amazon. Launched in 2014, Lambda offers execution environment for functions written in languages such as Python, C#, Java, Node.js, and so on. It automatically provisions and removes servers as per the traffic requirements. You don’t have to upload the entire app, only the required functions, then trigger it to run the service. Lambda offers ease of execution, improved app resilience, and a cost-effective solution. On the downside, there is no control over the environment.

API Gateway

An API gateway is an API management tool that enables you to create, publish, secure, and manage HTTP, WebSocket, and REST APIs. Acting as a reverse proxy, an API gateway receives various API calls, performs service aggregation to fulfill those calls and delivers the result. API gateways help you to protect your APIs, run analytics tools on APIs, connect a billing service, or manage older and deleted APIs, etc. In a serverless environment, resources are provisioned based on the API calls. An API gateway helps you to deploy and manage serverless functions. 

AWS Step Functions

AWS Step Functions is an AWS visual workflow tool that enables developers to break a process into a series of steps. Automation of IT processes, building distributed apps and machine learning pipelines becomes easy with this low-code service. You can quickly build and deploy reliable and highly scalable apps and manage stateful and fault-tolerant workflows with less integration code. 

Web Application Architecture Best Practices

Here are some of the best practices to follow while designing a great web application architecture.

Scalable Web Server

A scalable web server is critical to delivering consistent app performance regardless of the number of concurrent users, location, and time. There are three types of scaling options, namely horizontal scaling, vertical scaling, and diagonal scaling. While vertical scaling is about upgrading/downgrading the device configuration, horizontal scaling is about increasing/decreasing the number of devices. Diagonal scaling is about combining both models. Choosing a horizontal scaling model is recommended as you will not be limited by configuration or number of servers. Moreover, you can mix vertical scaling as and where applicable.

Adapt the Cloud With Elastic Infrastructure

With hybrid and multi-cloud environments increasingly becoming popular, adapting to the cloud and proactively provisioning resources is key to delivering high-performing web apps. Elastic infrastructure comes with preconfigured network systems, VM servers, storage, and compute resources, allowing to easily manage the environment with self-service portals. It gives the flexibility to quickly adapt to changing market needs and customer expectations.

Immutable Infrastructure

Simply put, immutable infrastructure is something that cannot be changed once deployed. It enables administrators to automatically provision resources using code. When servers are to be updated or modified, they are automatically replaced by newer ones. 

Configurational drift is a big challenge in mutable infrastructure. Scaling and debugging issues while replicating the production environment adds up to this challenge. Immutable infrastructure uses a validated and version-controlled image to provision new servers for every deployment. So, the previous state of the server is not a concern. You can test servers before deploying them. It eliminates configurational drifts and allows horizontal scaling while offering simple rollback and recovery with consistent staging environments. 

Microservice and Serverless Approach

Microservice and serverless computing are both critical to web application development. However, the difference is that microservice architecture offers a long-term solution with high scalability while serverless computing offers code efficiency. Serverless functions run only when they are triggered.  

By combining both models, you can gain the best of both worlds. You can use AWS Step Functions to assign triggers to combine several functions into a service and assign triggers to them. With event-triggered microservices, you can build a combined system to gain code efficiency, long-term stability, cost-effectiveness, and scalability. 

Multi-Tenant Architecture

Web applications are now being delivered as SaaS applications. There are two models to deploy SaaS apps: single-tenant vs. multi-tenant architecture.

• Single-Tenant Architecture: A single standalone environment is created for each organization comprising the infrastructure, software, and hardware ecosystem.
• Multi-Tenant Architecture: A single cloud environment with fully centralized services and logically isolated is shared by multiple organizations. 

For web apps, using a multi-tenant architecture offers multiple benefits. Organizations can manage a single code base for all users, reducing overhead and code conflict issues. It also reduces server infrastructure costs through economies of scale. Along with reduced development efforts, it brings faster time to market as well. 

Python/Node.js + React + AWS is the new trend in building SaaS web apps. 

Secure the Architecture With HIPAA, PCI, and SOC2 Guidelines

Building a secure architecture is a minimal requirement for any organization. Applying security protocols and policies not only secures your data and environment but it also helps you easily manage audit tasks and comply with government regulations. 

• HIPAA: Health Insurance Portability and Accountability Act (HIPAA) is an important requirement that health organizations are required to comply with. It helps in reducing healthcare frauds while securing private health information.
• PCI DSS: The Payment Card Industry Data Security Standard (PCI DSS) defines a set of procedures and policies for financial organizations that deal with sensitive financial data of customers. 
• SOC 2: SOC 2 auditing procedure is a key aspect in ensuring that your data is securely managed by the cloud service provider. While organizations don’t have to comply with SOC 2 guidelines, it is good to follow them to secure customer data. SOC 2 guidelines define the five trust service principles that customer data management is based upon.
• Availability
• Security
• Processing Integrity
• Confidentiality
• Privacy  

Automate Your Code Deployments in a DevOps CI/CD Environment

Deployment automation is about automating the process of code movement between testing and production environments with ease. It enables developers to quickly and frequently deploy code to production without human intervention. AWS offers a fully managed deployment service in the form of AWS CodeDeploy. It enables you to automatically deploy code to a variety of environments such as AWS Lambda, AWS Fargate, Amazon EC2, or on-premise.

Deployment automation is a part of a DevOps continuous integration/continuous deployment pipeline. It consists of three important phases: build, test, and deploy. When the code is written, it is automatically tested and added to the central repository. These changes are validated and added to the application. Automating testing runs a variety of tests at different levels to ensure that the code is error-free. Then the code is automatically deployed to production. 

Build Your Web Architecture With Infrastructure as Code Tools

Infrastructure as Code (IaC) is a method of automatically provisioning the infrastructure using code. It helps you to treat servers, network, database, and other IT resources as software and manage them using config files. As such, you can spin up resources instantly on-demand, manage configuration consistency, and eliminate configuration drifts while increasing software development efficiency. It reduces software development costs as well. Terraform and AWS CloudFormation are two of the most popular IaC tools.

Conclusion

In today’s highly competitive software world, creating quality products and services is not enough to gain the trust of customers. The way you deliver the products and services to your customers matters the most. Web applications help you to do so. As such, organizations are required to create and deploy highly optimized web apps that cost-effectively deliver the speed and performance and superior customer UI/UX experience to customers. Designing the right web app architecture is crucial here.