How to Build a Scalable Web Application: In-depth Guide

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When it comes to web application development, the online market never fails to leave us stunned. Currently, 1.13 billion websites are running on the internet in 2023.

Globally, Forbes Advisor statistics state that 71% of businesses already have a web application in 2023. Whereas, the other 43% of small businesses are still planning to invest more in improving their web application performance.

These are never-ending figures as there is still 1 web application building every 3 seconds; Too massive statics, isn’t it? But are you aware of the conversion rate of web-based applications under these multiple business domains? It is:

  • Ecommerce: 1.84% – 3.71%
  • B2B: 2.23% – 4.31%
  • Average Across Industries: 2.35% – 5.31%
  • Mobile App Store Page: 26.4% 

Got an overview of why the scalability of web applications is important. Well, there are several other factors we got for you as a guide to building a scalable web application.

Introduction to Web Application

Web-based applications are interactive web pages that run on web servers or we can say search engines that can be accessed through a website browser. Web app development gets done by both businesses and individuals for running an interactive program between information seekers and content providers.

This web application development is basically divided into front-end development for a user-friendly interface and back-end development to enable information exchange between both ends. So that the web application owner can have the data of web visitors, customer service/product interest, and feedback.

The difference between basic web services and webapp is that traditional web page get based on server-side developers whereas web apps have an application program interface (API). API based webapp development enables coders to sync data between multiple platforms facilitating automation in filtering results as the user side data and requirements.

The most common web applications that also appear on mobile devices are:

  • Facebook, Instagram, Twitter
  • Gmail, Yahoo, AOL
  • Query sites, such as Quora and Google
  • Self-service customer portals

Importance to Build Scalable Web Applications

Scalable architecture; reflects the flexibility of the application which stands for handling the volume of traffic, loading CSS, js, and php scripts without compromising performance or disruption in user experience.

To scale web applications higher, your entire application must be well-configured and aligns with protocols and hardware of requests per minute (RPM), as well as reduce downtime caused due to server crashes.

There are primarily two types of web application scalability you can consider to make your architecture pattern more robust; Horizontal Scaling and Vertical Scaling.

Let’s check out which one fits the best for you; Horizontal Scaling vs. Vertical Scaling:

Horizontal Scaling:

Also known as “scaling out”, is a scalable web application architecture that includes the procedure of increasing nodes and machines.

These practices result in the reduction of server load by distributing extra workload procedures on added nodes. In simpler terms, scaling horizontally includes the hiring of web application developers for an additional client/problem set.

Pros and Cons of Horizontal Scaling


  • Ensures improved performance by reducing server load.
  • Lesser downtime compared to vertical scaling.
  • Robust strength to handle a higher number of users.


  • Involve complex cross-server connections.
  • Slighter less consistency; making it unpreferable for application needs including simultaneous practices, transactions, and more RPM.
  • Least options for specific categorization.

Vertical Scaling

Whether Horizontal scaling stands for ‘scaling out’; Vertical scaling is known as ‘scaling up’. Vertical scaling reflects the addition of nodes and machines in the current web application itself.

This vertical scaling includes upgrading more resources such as CPU/RAM/DISK. If the current web application doesn’t scale more the company can also go for vertical scaling describing the replacement server entirely with a new one.

Vertical Scaling is most commonly used in applications and products of middle-range as well as small and middle-sized companies. One of the most common examples of Virtual Scaling is buying expensive hardware and using it as a Virtual Machine hypervisor.

Pros and Cons of Vertical Scaling


  • Includes no risk of managing multiple instances simultaneously.
  • Offers extended memory power and optimized RAM.
  • It doesn’t ask for additional code customization even at the time of implementation.


  • Might fail to respond to multiple queries due to having an entire load on one server.
  • If exceeds the specific server load; downtime can possibly increase.
  • As adding hardware to the existing web; the resources can get costlier.

Most Challenges Faced in Web Application Scalability

There are numerous design principles to consider when building scalable applications. But not to forget, when there is room for scalability, it includes some complexities too; concluding in the raising of common issues.

Application Code to Consider When Building Scalable Web

Suppose your scaling apps offer services of video streaming where customers can visit, can create their account, have a playlist collection, and share their videos too.

If you have an average code base, a request for a heavy video upload can result in a slower web application response rate for each user. To avoid such consequences you better break down such requests into the queue of multiple threads aligned with video size and traffic cookies.

Additionally, you can also draw these requests as an asynchronous background job that can state the estimated time and reason to users for getting results. Hence, your video streaming webapp will be all set to handle an increase in users and also provide a response rate aligned with scalability metrics.

Exceed Database Limitations

When designing scalable web applications; it is an obvious term of having a lot of content which results in a higher chance to gain hundreds of users in a shorter period.

Now, each user must have a unique query; for example: if a user has a query of modern web content on the blog then the SQL database will loop the query by conducting one SQL query and then the other.

These types of queries are known as N+1 queries, which poorly affect the scalability of a web app. To optimize such SQL queries; you better implement indexing strategies that can conclude in keeping efficient records of categorization, date, author, and read time.

Scale the Application with Multiple Hardware Resources

Web applications that can process the most complex procedures in the least time have the most increased number of users.

But, if the entire back-end procedure will be conducted on a single server it’s quite challenging to achieve the same. This is why breaking down these workloads on multiple hardware resources is suggested.

For instance, if your web application needs to be wholly revamped you can conduct that too which provides the result to each search without downtime and improved performance of the application.

Steps for Building a Scalable Web Architecture

Building a scalable architecture isn’t about just adding more servers; it’s about strategic planning and a deep understanding of how components interact. In this section, we will outline crucial steps to ensure that web application isn’t just functional but also scalable to meet future demands.

Define the Scalability of an Application

To create a scalable web application, first, you’ll need to define the scalability issues and expected challenges to resolve them. To be specific with the current scaling scenarios and your expectation you’ll need the right metrics.

Here are the main four scalability metrics you must analyze:

  • Usage of memory
  • CPU usage
  • Network I/O
  • Disk I/O

Right Infrastructure to Make Your Web Application Highly Scalable

If you want to do it all by your knowledge, connecting with PaaS services providers is the best way to do so. PaaS (Platform as a service) is basically a cloud computing business model providing hardware and software tools needed to make the application scalable.

There are multiple checkmarks of to-do list get handled by these tools including:

  • Infrastructure
  • Networking
  • Servers
  • Storage
  • Middleware
  • Operating system (OS)
  • Runtime environment
  • Database
  • Easy integration with 3rd party service providers

Right Architecture to Create Scalable Web Applications

Scalable web app principles involve the right architecture base that helps web apps to be tailored as per the user demand and offer the most suitable performance.

Even the slightest error in architecture can impact the scalability which is crucial in choosing the best for your enterprise.

Here are the two most popular and preferred architectures to create highly scalable web apps: Monolithic Architecture vs Microservices Architecture.

Monolithic Architecture:

Also renowned as a traditional model of software program is an in-built unified unit containing nodes, networks, and resources independently from other hardware applications.

This monolithic architecture is a distinct architecture with a robust code base that couples other businesses together; making it a base of the web application.

The updating procedure in this monolithic application includes editing the entire stack by accessing the code base and deploying the updated code version on the service-side interface.

Monoliths is a great architecture to scale your web app. If you want to build web apps with ease in code management and deployment; monolithic is the one. One of the main drawbacks includes development downtime.

Microservices Architecture:

You can consider it as completely opposite of the Monolithic; as this architectural method includes a series of independently deployable structures.

Microservices offer good application monitoring solutions as it includes independent business logic and database. The primary advantage of microservices is that even after updating, testing, and deployment specifically on a particular structure it won’t create any negative impact on your web app.

With microservices, you can also make things more manageable by dividing a particular task independently into a dedicated sector while making contributions to the overall role in building a scalable web.

Make a Scalable Web With the Right Database

When it comes to choosing the right database to make a scalable web, there is no one-size-fits-all solution. First, you’ll need to understand some of the characteristics including:

  • Business requirements
  • Data aspects
  • Trade-offs
  • Features
  • Benefits
  • Flexibility
  • Drawbacks

When comparing one with another you’ll get an option to pick the one tailored exactly to your business needs.

Also, consulting with experienced web app developers can also result in using two database languages to strengthen the base. Some of the common coding languages used are NoSQL with databases of:

  • MongoDB
  • Cassandra
  • Redis
  • Neo4j

Building a Web App With Higher Scalability Using Proper Framework

Framework plays an important role in building a scalable web as its practice decides the tenure of how long the existing web app will remain scalable. Depending on the framework you choose; there are multiple features you can add or quit. Here is the list of best frameworks to build higher-scaling web applications:

Django for Scalable Web Application:

Django is an open-source web application development framework based on Python. Django is personally designed for handling heavy traffic sources and APIs with the in-built potential of creating fast, secure, and scalable web applications.

Ruby on Rails for Scalable Web Applications:

Also known as Rails is a server-side framework for web application development written in Ruby programming language. Ruby on Rails is famous among businesses and developers because of its incredible managing capacity of users, clients, or consumers ensuring steady app growth.

Node.Js for Scalable Web Application:

As it is open-source and cross-platform, Node.Js is a popular javascript framework for any kind of web application project. But as Node.js utilizes a single thread to manage non-blocking I/O calls, it can take fewer resources for the application to accept concurrent connections compared to traditional approaches.

Tips to Consider When Building Scalable Web Architecture

Till now you cleared checkmarks to learn how to build a web application that can scale higher with its importance. Also studied the important role of picking the right architecture, infrastructure, and framework.

But for achieving the desired infrastructure and architecture aspects results and managing it for a longer time you better follow the steps mentioned below:

Remove Workload from the Core:

It is better to divide work procedures into individual blockchains as it will clear up scaling-up bottlenecks.

Purge the Cache of Your Web Application:

Cache stores data that can be recovered faster as answers to queries. Hence, caching significantly improves the scalability of web applications.

Maintenance and Process Automation Design

Regularly monitoring the web app scalability including appropriate software updates and app maintenance will ensure smooth performance.

FAQs About Web App Scalability

What is scalability in web app development?
Scalability denotes the application's ability to handle numbers whether it is one or a thousand users. Web app scalability directly relates to the ability of current and future web app development to maintain the app and its data consistency.
How do you increase the scalability of a web application?
  • Define the Scalability Of An Application
  • Choose the Right Infrastructure
  • Prefer High Performing Architecture
  • Ensure a Robust Database
  • Pick a Scalable Framework
What is used for building scalable web applications?
Mostly frameworks including Django, Ruby on Rails, and Node. JS is the most preferred option for building scalable web applications.
What makes an application scalable?
  • Right Infrastructure
  • Robust Database
  • Scalable Framework
What is the cost of building scalable web?
The cost of applications depends on many factors such as daily active users, current sales, scalability of the database, and common web design technologies tailored best for your business.

Create a Scalable Web App

Whatever size of business project you want to build; whether for a startup or a well-established business, scalability is the most important point to consider when planning to invest in web applications.

Not to forget, there are several other factors you need must check out first – our guide on Building Scalable Web Applications covered it all! Helping to pick out the best for your business. Undoubtedly, you might have some other queries or requirements too. For getting assistance on the same get in touch with our expert web developers now!

Jigar Shah is the Founder of WPWeb Infotech - a leading Web Development Company in India, USA. Being the founder of the company, he takes care of business development activities and handles the execution of the projects. He is Enthusiastic about producing quality content on challenging technical subjects.

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