Everything You Need to Know in 2024 about Application Architecture

Web application architecture refers to the overall structure of a web application. It encompasses the relationships and interactions between the various application components. The architecture provides a blueprint for how the application will be built, deployed and executed.

In simpler terms, web application architecture is the backbone that supports and ties together all the parts of a web application. It serves as the foundation on which developers can build and expand the application.

The main objectives of a well-planned web architecture are:

• Define how the application components will work together
• Provide scalability as per business needs
• Ensure flexibility to accommodate new features
• Build in security across components
• Enable easier maintenance and updates
• Optimize performance and speed for users
• Reduce complexities for developers

The architecture sets the stage for how amenable the application will be to change and growth. A sound web architecture makes the application resilient, efficient and helps avoid common pitfalls like security risks, performance lags, rigid structures etc.

Components of Web Application Architecture

A web application architecture comprises two fundamental components:

Client-side Components

The client-side components are the UI (user interface) elements that run inside the user’s web browser. These include:

• HTML, CSS, JavaScript – Used to build the visual interface
• Frontend frameworks like React, Angular, Vue – For developing interactive UIs

The client-side components handle the presentation layer and UI logic. They manage user interactions and communicate with backend servers as required.

Server-side Components

The server-side components power the core application capabilities and business logic. They reside on web servers and include:

• Web server – Serves client requests and handles HTTP requests and responses
• Application server – Runs the backend application logic and business rules.
• Database server – Stores and manages application data
• Runtime environments – Software frameworks like Node.js, Spring etc on which apps are built and run
• Operating Systems – Linux, Windows on which the servers run

Together, the client-side and server-side components enable web applications to deliver dynamic and interactive user experiences. The client components handle UI display while server components do the heavy-lifting of business logic, data storage and processing.

Interaction between components

The typical flow between client and server components is:

• The user interacts with the UI components rendered on the browser
• Actions get translated to HTTP requests and sent to the web server
• The web server forwards requests to the application server
• Application server executes relevant business logic
• Needed data gets retrieved from the database server
• Application server sends back the response to the web server
• Web server conveys the response to the client-side UI
• The UI gets updated with new data and displays it to the user

This request-response cycle drives all user interactions. The separation of responsibilities between client and server components enables building specialized expertise and rapid parallel development.

There are several architectural patterns used for web application development. Each has its own pros and cons. The most popular options include:

1. Monolithic Architecture

In a monolithic architecture, the application is built as a unified unit where all components are interconnected and interdependent.

Pros:

• Simple and easy to develop as a single unit
• Easy to deploy as one deliverable package

Cons:

• Tight coupling makes scaling individual components hard
• Change in one component affects others
• Adds complexity as application grows

Monolithic apps are suitable for smaller applications. For larger applications, modular architectures are preferred.

2. Multi-tier / N-tier Architecture

In this model, the application logic is structured into layers such as presentation, business logic, data access etc. Each layer has distinct responsibilities.

Pros:

• Loose coupling between layers
• Enables scaling each layer independently
• Good separation of concerns
• Easier to maintain and update

Cons:

• Adds some complexity in development
• Requires coordination between teams working on different layers

The n-tier model is widely used for enterprise web applications due to its flexibility and scalability.

3. Microservices Architecture

This is an extension of the n-tier architecture. The application is built as a suite of smaller modular services where each service has its own specific capability and runs independently.

Pros:

• Highly maintainable and testable
• Easy to scale and update individual services
• Promotes component reusability
• Better fault isolation

Cons:

• Higher operational complexity
• Trickier to debug and monitor
• Requires good DevOps practices

Microservices are ideal for large web apps needing frequent updates, dynamic scaling and easier maintenance.

4. Service-Oriented Architecture (SOA)

SOA focuses on building modular and reusable application services that can be leveraged across multiple channels. The services communicate via APIs and standardized protocols.

Pros:

• Services can be reused across apps
• Platform-independent architecture
• Simplifies integration between systems
• Improved scalability and flexibility

Cons:

• Complex coordination between services
• Rigorous versioning needed
• Tight coupling if not designed correctly

SOA is best suited for enterprise integration scenarios.

5. Serverless Architecture

In a serverless model, application logic runs on stateless compute containers that are event-triggered and fully managed by cloud vendors. The server infrastructure is abstracted away.

Pros:

• No server management overhead
• Auto-scaling built-in
• Usage-based costing
• Faster time to market

Cons:

• Vendor dependence
• Monitoring and debugging difficulties
• Application complexity if not properly architected

Serverless is ideal for apps with variable traffic and the need for quick scaling.

Within web architectures, the multi-tier model separates concerns into different layers. Some popular examples are:

1. Two-tier architecture

Contains just two layers – one for client-side UI and the other for server-side business logic and data access. Simple but lacking flexibility.

2. Three-tier architecture

Most commonly used pattern. Separates UI, business logic and data access into three distinct layers. Provides loose coupling.

3. Model-View-Controller (MVC)

Splits app into Model, View and Controller components. The model handles data, view manages UI and controller processes logic and user inputs. A very popular pattern that promotes separation of concerns.

4. Model-View-ViewModel (MVVM)

Evolution of MVC for modern UIs. The viewmodel mediates between the view and model components. Synchronizes data between UI and business logic. Used heavily in JavaScript frameworks.

The multi-tier model allows easier maintenance, testing and parallel development by logically dividing the application into specialized layers. The patterns provide proper separation of concerns following best practices like SOLID design principles.

5. Microservices Architecture

Microservices architecture (MSA) is rising in popularity for modern web application development. It structures apps as collections of loosely coupled services where each service implements specific business capabilities.

Benefits of MSA:

• Services can be developed, deployed and scaled independently
• Technology flexibility – each service can use different technology stacks
• Promotes component reusability
• Parallel development by decentralized teams
• Improves fault isolation and enables continuous delivery

MSA is best suited for complex, data-driven web applications that require frequent updates, dynamic scaling and complex business logic. The decentralized governance also encourages innovation across teams.

However, MSA also brings its own set of challenges:

• Increased deployment and operational complexity
• Difficult debugging and monitoring
• Need for good DevOps and infrastructure automation
• Rigorous versioning needed for services
• Repeated components and toolkit dependencies

With its benefits significantly outweighing the challenges, MSA has cemented its place as a pivotal architecture for enterprise-scale web applications.

6. Progressive Web Applications

Progressive Web Apps (PWAs) are a relatively newer category of web apps that use modern web capabilities along with a service worker to deliver native app-like capabilities.

Characteristics of PWAs:

• Installable – Added to home screen and used offline
• Responsive – Adapts UI across form factors
• App-like – Provides immersive experiences
• Always updated – Gets latest features and fixes
• Safe – Served over HTTPS for security
• Discoverable – Easily shared via URL
• Re-engageable – Send push notifications
• Linkable – Easily shared via URL
• Progressive – Works on any browser or device

PWAs offer the best of web and mobile apps. They provide reliable, fast and engaging experiences across devices. PWAs are web apps at heart but go beyond traditional web capabilities. Technologies like service workers, web manifests and push APIs provide native app features.

For users, PWAs offer:

• Fast performance with offline support
• Smooth interactivity and animations
• Immersive full-screen experiences
• Easy access from home screen
• Latest updates when available

For developers, PWAs enable:

• Coding with web standards and skills
• Easier cross-browser testing
• Feature parity on all devices
• Frictionless distribution outside app stores
• Low development costs

As smartphones get more powerful and web capabilities evolve, PWAs present an extremely promising alternative to native mobile apps.

Web Application Architecture Tools

A wide range of tools are available for developing, visualizing, and managing web application architectures:

• Programming Languages – JavaScript, TypeScript, C#, Java, Python, PHP, Ruby
• Frontend Frameworks – React, Angular, Vue, Ember
• Backend Frameworks – Node.js, Django, Rails, Laravel, Spring
• Databases – MongoDB, MySQL, PostgreSQL, SQLite
• Design and Modeling Tools – Lucidchart, Draw.io, PlantUML
• Wireframing Tools – Figma, Sketch, Adobe XD, InVision
• DevOps Tools – Jenkins, Kubernetes, Docker, Ansible, Terraform
• Testing Frameworks – Jest, React Testing Library, Cypress, Selenium
• Monitoring Tools – New Relic, Datadog, Grafana, AWS CloudWatch
• Cloud Services – AWS, Azure, GCP for hosting, serverless, storage
• Code Repositories and Collaboration – GitHub, BitBucket, GitLab

Choosing the right combination of technologies aligned with team skills and project needs is key for web architecture success.

Web Application Security Architectural Considerations

Some key ways a sound web application architecture promotes security:

• Applying the principle of least privilege via access controls and separation of duties reduces insider risks.
• Encrypting sensitive data in transit and at rest prevents unauthorized access
• Multi-factor authentication and centralized identity management avoid account compromise.
• Using parameterized queries, input validation, and sanitization prevents code injection risks like SQL injection and cross-site scripting.
• Implementing layers of defense via firewalls, web application firewalls, IDS/IPS systems mitigates external threats.
• Implementing layers of defense via firewalls, web application firewalls, IDS/IPS systems mitigates external threats.
• Regular security testing, audits, and risk assessments identify vulnerabilities proactively.
• Monitoring user sessions and network traffic helps detect anomalies and prevent fraud.
• Applying security updates promptly and maintaining visibility into dependencies minimizes risks from known vulnerabilities.

A holistic focus on security throughout the SDLC, supported by a layered, robust architecture reduces the application’s attack surface significantly.

Differences Between Web and Desktop Application Architecture

While web and desktop apps both deliver software capabilities to end-users, they differ fundamentally in their architectures:

• Desktop apps install natively on user devices and interface directly with the OS. Web apps run remotely on servers and are accessed via browsers.
• Desktop apps can leverage all local resources and hardware. Web apps have limited local device access constrained by browsers.
• Desktop apps offer speed and fluid UIs as everything runs locally. Web app UIs have some lag due to network communications.
• Web apps centrally manage data and business logic on servers. Desktop apps rely on local processing and storage.
• Web apps seamlessly deliver updates to all users. Desktop app updates have to be packaged and installed individually.
• Web apps accessible instantly from anywhere via URLs. Desktop app usage can be limited by physical presence on the device.
• Web apps can struggle with intermittent connectivity. Desktop apps are reliable as connectivity issues don’t hamper local components.

While web apps promote universal access, desktop apps provide richer interactivity and speed by utilizing local resources fully.

REST APIs in Web Architecture

Modern web architectures extensively use REST APIs to connect their various components and services.

REST (Representational State Transfer) is an architectural pattern for creating lightweight and scalable web services. It leverages HTTP protocols for client-server communication.

Here is how REST APIs fit into web application architecture:

• Enable flexible integration between front end UI and backend
• Expose core application logic and data as reusable services
• Allow consuming services from diverse platforms – web, mobile, IoT etc.
• Simplify orchestration between microservices and integration with other systems
• Provide extensibility for future integrations
• Handle complex workflows under the hood
• Abstract underlying implementation details
• Handle security, rate limiting, metrics etc

Well-designed REST APIs are key for building performant and scalable web applications. They encapsulate business logic behind a uniform interface. Frontend components can consume these APIs to fetch data and execute app capabilities.

APIs act as the connective tissue between modern web app components. Backend services like microservices also use REST APIs for inter-communication. This leads to loose coupling, better scalability and tech flexibility across the stack.

DevOps Role in Web Architecture

The emergence of DevOps has significantly impacted modern web application architectures. DevOps principles are integral to crafting architectures that support continuous delivery, faster release cycles and agility.

Here are some key DevOps enabled practices for web architecture:

• Infrastructure as Code (IaC) – Managing infrastructure via code for automation and consistency
• Continuous integration – Merging developer commits frequently to detect issues early
• Continuous delivery – Automating build, test and release processes
• Microservices – Architecting apps as sets of autonomous services
• Monitoring and observability – Tracking metrics for all components
• Progressive feature rollout – Releasing features gradually to subsets of users
• Infrastructure automation – Scripting admin tasks to minimize human errors
• Polyglot persistence – Using optimal data stores for each service
• Declarative configuration – Defining app config as code under version control
• Self healing – Designing for failure resiliency and auto recovery

By incorporating these and other DevOps patterns, web architectures can achieve the velocity, safety and adaptability needed to stay competitive.

Let’s look at some of the noteworthy trends shaping modern web application architectures:

API-first Design

Designing APIs first decouples backend services from client components. It provides flexibility to expose core capabilities to diverse platforms.

Micro Frontends

Micro frontends partition the UI into distinct components owned by different teams. This accelerates development.

Headless Architecture

Here the front end UI layer interacts with the backend via APIs only. It removes tight backend coupling.

Cloud Native Development

Architecting apps to best leverage cloud platforms and managed services for resilience and agility.

Low Code Platforms

Empowering citizen developers to build apps visually with prebuilt components and minimal coding.

JAMstack

Using JavaScript APIs, reusable Markup and prebuilt Markup to build fast dynamic sites without web servers.

Everything as a Service

Consuming modular capabilities like data, messaging, functions, notifications etc. on demand as managed services.

Serverless Computing

Building apps using event-triggered, auto-scaling functions without managing underlying servers.

These trends point to increased modularity, abstraction of infrastructure, rapid composability and assembling applications with cloud-native building blocks. Web architecture is shifting away from monoliths to flexible compositions of specialized components.

Here are some guiding principles and patterns that are key to crafting optimized web architectures:

• Separation of concerns – Isolate components based on capabilities for loose coupling. Examples are MVC, layered architecture.
• Encapsulation – Hide component implementation details from other parts of the app to reduce dependencies.
• Single responsibility – Each component should do one job well and not take on too much
• Driver and worker components – Driver components coordinate workflows. Workers do specific tasks.
• Stateless components – Components should manage minimal state to enhance robustness and scalability.
• Fail fast principle – Uncover errors early via testing, assertions, automated checks to prevent bigger failures.
• Caching – Store data, pages, etc. closer to the client to improve performance and reduce repeats.
• Asynchronous processing – Use message queues, workers, etc. to handle resource-intensive tasks asynchronously.
• Graceful degradation – App remains somewhat functional even with disrupted components or connections.
• Use of design patterns – Factory, repository, facade patterns promote qualities like flexibility, testability.

Adhering to sound principles enables building web apps that are robust, scalable, and maintainable despite increasing complexity.

Some key strategies to optimize web application performance from an architecture standpoint:

• Implement client-side caching for static resources so browsers can reuse them without roundtrips.
• Enable compression for traffic between clients and servers to reduce bandwidth usage.
• Use CDNs to distribute resources closer to users to avoid distant network trips.
• Design async communication patterns so endpoints can work independently without blocking.
• Set sensible timeouts for requests and tasks to avoid hanging processes.
• Choose simple, fast algorithms and queries over unnecessarily complex logic.
• Limit excessive database calls by getting required data in batch via join queries.
• Design idempotent operations so repeating requests won’t corrupt state.
• Use service workers for offline support and fast page loads on repeat visits.
• Containerize apps and embrace cloud-native patterns for elastic scalability.

Continuous performance testing, monitoring, and tuning ensures optimal speed over time as the system evolves.

TAV Tech Solutions is a leading software development company specializing in offering a complete range of software service and technology solutios across industry verticals. The company continues to assist global businesses in achieving their business goals through its web architecture services. Backed by an extensive team of proficient developers they have several years of technology and domain expertise, TAV Tech Solutions believes in adding value to every project they work on.

We have only scratched the surface of the depth and breadth of web architecture in this guide. There are entire books written about each specific architecture style and patterns.

The key is to understand your unique functional and non-functional requirements, and adopt an architecture that best fits your needs while allowing future growth. Leverage existing patterns but don’t rigidly enforce them if they don’t suit your app.

Keep performance, security, scalability and agility as the guiding principles for your architecture. As long as you internalize the core concepts shared in this guide, you will be able to make informed architecture decisions and adapt as technology evolves.