How to Build Scalable Web Application: Strategies, Tips, Pitfalls

The scalability of technical products is an important topic that affects IT business development in one way or another. In simple words, it is the ability of the software, web applications, mobile apps, etc., to withstand heavy loads with a sharp increase in users who use it simultaneously.

However, the issue of scalability is much deeper and more complex. In this article, we will discuss all its nuances, architectural features and components. We'll also look at scalability's benefits and talk about how to create a scalable web application.

A Few Words About Web App Scalability

So, the scalability of web applications is about the ability to function flawlessly with high traffic and a significant workload. This concept is key for businesses planning expansion and development in the future, as this is the only way for web products to cope with the changes caused by adding new resources and system improvements.

Scalable web applications have an architecture that easily adapts to changing workloads. Databases, the interface, the server and its capabilities – all this remains stable with a sharp increase or decrease in traffic. Regardless of the conditions, users get access to the full functionality of the application without delays.

man and web app

Benefits of Building a Scalable Web App

Scalability brings many benefits to tech businesses. First of all, it helps the system maintain stability in case of high workloads when the audience of users increases. This way, the costs of attracting and supporting new customers are reduced.

Secondly, the design of a scalable solution from the first steps of development helps to reduce resource costs for software maintenance and improvements in the future.

However, these are not the only advantages. There are a few more key points.

Improved Productivity

The smooth operation of web applications is critical for businesses with a large target audience that is constantly growing. When the product is created for general purposes and not for corporate usage by a limited number of users, scalability solves the performance issue. 

The loading speed will also decrease with the application's functionality expansion and the increase in traffic. The capabilities provided by web application scalability reduce rendering time.

This is a way to improve and stabilize the product significantly. It will meet all users' needs, preventing business downtime and loss of profit.


Security is a key issue in digital business. In 2021, global losses from cybercrime amounted to $16.4 billion per day, and according to expert forecasts, by the end of 2022, the total loss may reach $6 trillion.

Any software, especially one that collects and stores sensitive data, needs enhanced security measures. And scalability in the form of cloud solutions, database replication, opportunities to involve AI, etc., provides the necessary protection.

Cyber Statistics 2022
Source: Financeonline


Scalability is all about advanced network server solutions and cloud technologies. This helps to improve and change the system in different regions. Thus, the product is globally available to every user.

Opportunities for Improvement and Development

Scalable apps have room for new features, changes, and improvements. Therefore, if you plan to expand your business and develop a technical product, you need to build a scalable web application from scratch.

Summing up, scalable web products can handle high loads, have room for improvement, and allow using advanced security tools. All this together forms another significant advantage – cost savings.

Such solutions require fewer resources for expanding functionality, maintenance and management. They also require less effort to resolve problems and emergencies.

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What Characteristics Affect The Web Application Scalability?

There are several main factors that can affect the scalability of web products. Let's take a closer look at them.

  • Architecture. This is the main factor affecting a web application's ability to change and expand. Scalable web application architecture and clean code are critical to successful scaling.
  • Hardware. The simplicity of software management, the ability to add new functions and maintain its performance depend on this factor.
  • Framework. The framework affects the performance of the web product when updating and expanding functionality. In addition, each option has its limitations. Therefore, you should be careful when choosing it.
  • Third-party integrations. Third-party services have their limitations, architectural and performance features. Of course, they affect the software and can cause failures in its operation.

It is also worth paying attention to timely sustainable load testing. At a certain point of workload intensity, the system fails. The task of such testing is to determine the transition point from predicted growth to abnormal load jumps, as well as system bottlenecks.

In this way, it is possible to get rid of shortcomings, ensure smooth load growth and improve the product's scalability.

Scalable Web App Architecture

To develop a scalable app, it is worth paying attention to some key details of its architecture, which will ensure product flexibility and its adaptivity to changes. We will consider several critical points that can guarantee the system's stability when the load increases.


Frontend is all about user-product interaction. This is an interface component of the web architecture responsible for presenting features, access to them and a comfortable user journey.

A high-quality frontend leaves room for interface improvements and transformation of the visual component in the future. In addition, it has a top-notch UI/UX design that makes interaction simple, entertaining and accessible in all conditions.

In many ways, the frontend availability and performance depend on the backend. However, many frameworks and tools help handle difficult-to-load content with no extra effort.


Backend is about the server part of web applications; it's the core of their architecture. This component is responsible for interpreting user actions in the interface, processing requests and correct responses to them.

The server architecture is the foundation of the application's performance and it takes up most of the code. The backend provides dynamic processes and data management, so it needs special attention. A scalable backend is a flexible infrastructure and a minimum of bottlenecks.

Multi-tier Architecture Model

Multi-tiering involves building a web architecture based on three components or layers:

  • client-side server;
  • application server;
  • database server.

These are three different modules that perform only necessary functions. So, for example, the client side of the component is responsible for client interaction and the experience of using the application so it fulfills particular users' needs. The database component, in turn, provides data and access management; and the application server is responsible for running the program.

As we can see, the multi-tier architecture unifies the client software and relieves the database server of unnecessary actions. Since each component is not burdened with additional functions, scalability and performance are significantly higher. In addition, the distribution of roles can occur through the interaction of different modules.

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Horizontal Scaling

Horizontal scaling involves dividing sequential blocks of logic into smaller parts and distributing the tasks of data collection and storage tasks between the capacities of several physical machines combined into a single network.


Horizontal scaling is about reliably balancing the load using clustering and distributed file systems. This approach provides a high level of fault tolerance and more effective traffic regulation when demand increases.

It is also a good solution for minimizing geo-latency and expanding the geographical coverage of the web application. Horizontal scaling enables the deployment of an unlimited number of machines to handle workloads, providing a very high level of flexibility and wide configuration options.


Data transfer between machines during horizontal scaling occurs using "calls". Such calls fail in a poorly optimized scaling environment and may be too slow. The processing of different requests by different machines leads to the transmission of incorrect data to the client.

Developers can solve this problem in different ways; most often, they resort to implementing stateless scalability.

Vertical Scaling 

Vertical scaling is "concurrent programming" on a single physical machine that can have multiple cores. Developers optimize the power of a specific machine due to multithreading or internal data exchange. Scaling occurs according to the principle of interprocess communication.


Because vertical scaling involves using a single system, it is easier to implement and maintain. Also, with this approach, the risk of program incompatibility is minimal.

Another advantage of vertical scaling is the ability to use the same code to run on a machine with wider specifications. In other words, there is no need to change the logic of the process when expanding.

It is also worth noting that such a process does not require a load balancer since all data is processed on a single machine. This is an inexpensive and cost-effective option.


The fact that all processes take place on one machine has not only advantages but also pitfalls. Firstly, such a solution is not suitable for large projects but rather for small companies with lower bandwidth requirements.

Secondly, such scalability cannot provide wide geographical coverage, so it is most often used for companies with a local geographical presence.

Also, since a single machine handles all workloads, the scale-out environment is more conducive to downtime.

Replication and Sharding

Database management is vital to product scalability and performance. An increase in requests and data amounts leads to system slowdowns and downtime.

To improve the situation, developers are looking for ways to reduce the load on the central database. It can be replication – creating copies of data sets, or sharding – data segmentation.

In the first case, the load is reduced by processing certain parts of requests through the network and creating a reliable data recovery system. In the second – thanks to the distribution of data through several databases and adding more nodes with an increase in the user flow.

web apps on different devices

Scalable Web App Principles

The concept of scalability is inextricably linked to the ability of software to recover from failures quickly. The following principles help in building scalable web applications capable not only of unlimited improvement but also of rapid recovery.

Wide Availability Principle

Continuous availability is an important principle that helps companies maintain their reputation and profitability. Even the smallest failures in the operation of web software, especially if it is a product of the financial or insurance sphere, cause irreparable harm to a company's credibility.

That is why every user should have access to all app's features always and everywhere. SaaS and cloud-based solutions are excellent choices in this regard. They provide access to the website anytime and under any conditions.

Smooth and Stable Performance Principle

App performance should be not only high but also stable. This is important both for customer satisfaction and interaction with search engines because websites with good smooth performance are much better indexed. It is necessary to hire a dedicated software development team with extensive expertise in creating scalable software to follow this principle.

Manageability and Adaptability Principle

The design of scalable products' infrastructure ensures total fulfillment of functional requirements with a concise implementation. This is the principle of manageability: a web application code should be easy to update, change and maintain, as well as deploy on different platforms, then the product itself will be easy to update and operate.

As for adaptability, everything is simple and plain: scalable applications can easily adapt to users' needs, market challenges, and business or technological changes. It is crucial to pay special attention to this issue because adaptability is not only about convenience and success but also about risk management and product prospects in the rapidly developing digital world.

Principle of Continuous Defects Traceability and Regular Testing 

The easy-to-use scalable web application system must be regularly updated and tested for problems and defects. It is very important that all bugs are fixed on time and quickly. This is possible thanks to the correct segmentation of the system components and the creation of the proper structure.

Principle of Fast Data Operation

Data operation affects application performance, so developers have to find ways to manage databases properly. Third-party tools and technologies are often used for this.

It is also essential to ensure the web application's reliability and security. This issue also applies to the collection, storage and processing of data. The principle of fast operation involves compliance with advanced security and data protection protocols.

web app on chrome

Scalable Design Methods And Strategies

There are many ways to make the application scalable. We will discuss best practices and techniques that ensure flexibility and performance in web products.

Service-Oriented Architecture (SOA) and Independent Components

The main principle of Service-Oriented Architecture or SOA is that each application component has its own functionality, context and purpose. At the same time, its changes and operations shouldn't affect other services' and components' functioning, although all parts remain competently connected.

The microservices architecture helps to divide the nodes and features of the web application into independent modules. This is an example of how you can manage components individually, expand functionality and update it without affecting the entire system.

Proper structuring also helps isolate certain problems in such a way that the bugs of one service do not affect the others. This is the basis of designing scalable web applications: the ability to solve problems, add features and update software without stopping the entire system.


Indexes inform about the location of specific pieces of data distributed among different servers or cloud storages. Indexing is an efficient database management method because it directs a user's query to a specific location, reducing response time and simplifying searches.

This is a good option, but not universal. Data tables can be too cumbersome in the case of large products that serve a huge user flow, so you'll have to consider different ways to apply them properly.

Asynchrony and Queues

Any operation requires a system response to a user request. When many such requests are simultaneous, the waiting time increases, and the app becomes slower.

Asynchrony and using tools such as Queue.js is the solution to this issue.With the increase of the program's functionality complexity, the number of user requests also increases. Running some requests asynchronously and creating queues helps speed up the process by executing specific requests while others are being processed.

Caches and Banalcers

Cache configuration is another effective way to handle the rapidly growing number of requests and queries. Temporary memory can work as a small "storage", where the data of frequent requests will be stored.

The essence of using a cache is simple: it makes no sense to process requests with a high frequency from scratch. If the user previously performed certain operations, the probability of their repetition during his next visit is very high. In order not to overload the system with repeated processing and reduce the response time, caching allows to save the results of requests and apply them faster.

How to use this tool correctly? There are several options.

  • Distributed cache is a method of distributing request data across all nodes.
  • The global cache is one common "storage" for all nodes.

Implementing this or that option depends on web product features, so the decision is up to the developers.

Balancers are traffic distribution tools. They redirect it to multiple nodes and improve routing when the number of requests jumps. In terms of scalability, balancing dramatically large traffic is very important. Balancers can be used together with caches for better results.

Proxy Servers

It is a multi-server request coordination tool that often collapses identical requests into one to speed up the operation and reduce the load on the database. Together with the cache, the proxy significantly speeds up request execution time.

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What Is The Cost Of Building Scalable Web Applications?

The costs of scalable web application development depend on many factors. Here are the main ones.

The size of the organization. Obviously, the development of scalable applications for small startups does not require such funds as the creation of a product for a large business.

  • Development strategy. Whether the company needs to purchase its own equipment and hire developers to follow the strategy or outsourcing to Eastern Europe will be a more profitable option.
  • Scale indicators. This can be the need for new RAM, CPU usage, time spent sending data from one monitored process to another, etc.
  • Database. Relational (MySQL or PostgreSQL) or unstructured (NoSQL database).
  • Framework. The rate of Angular developers and Node.js developers can be different.

In most cases, scalable SaaS startup costs dramatically depend on web product functionality, business needs, user needs and development team composition. We'll be happy to provide you with all the necessary information on this topic; just contact us in any convenient way.

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The Most Popular Scalable Web App Frameworks

The choice of a framework for developing a scalable product depends on the business needs, the goals of the application and its complexity. We'll talk about the most popular options.






Spring is a Java back-end framework that is comfortable for those who are used to coding in Java and its ecosystem. This is a good option for creating high-performance applications with a microservices

  • A huge community of developers and Oracle support

  • Suitable for various tasks, including providing top-notch website security

  • Clear and reliable documentation

  • Flexibility

  • Difficult learning curve

  • Rarely suitable for pattern coding

  • Complexity


Angular is a Google framework that was created for the company's internal needs and only later was presented for widespread use. This is a top-rated solution used for YouTube, Google Search and other company products.

  • Very detailed documentation. Angular has perhaps the best framework documentation: code examples, regular updates and a clear structure.

  • Code reusability

  • Unique possibilities for third-party libraries and tools integration

  • Perfect for developing dynamic and interactive web applications

  • Google Materials support

  • Independent structure of components and services

  • Asynchronous coding

  • More suitable for creating one-page web products

  • Complex adaptation

  • Difference in versions


Node.js is a solid framework used by giants such as Netflix and PayPal. The main feature is that the framework presents an event loop as a runtime construct instead of as a library.

  • An asynchronous, event-driven JavaScript runtime

  • Makes request processing and load balancing much easier

  • Cluster module function

  • Event-loop mechanism

  • Microservices architecture 

  • Up and down scaling options

  • Unstable API

  • Limited library integrations


Laravel is a PHP framework with full functionality for backend development and the ability to create interfaces based on React or Vue. A good option for small websites.

  • Convenient starter development kits

  • Laravel "Eloquent" ORM for working with databases

  • Queuing system

  • API support

  • Large learning base (Laracasts)

  • Server-side rendering

  • Limited opportunities for interface development

  • Monolithic architecture

  • Difficult learning and adaptation curve

  • Not suitable for complex web application


Ruby on Rails or RoR is a full-stack framework for dynamic, high-performance web applications. It is used by such platforms as GitHub, Shopify, Airbnb, Hulu, etc.

  • High load speed and performance

  • Functionality for database-driven applications

  • Asynchrony and queues

  • A good solution for cloud-based web applications

  • Controllers for processing requests

  • Solid community and detailed documentation

  • Low flexibility


Django is a full-featured server-side web framework based on Python. It has an excellent web development environment. The main framework principles are following the principle of "Convention over Configuration" and using the DRY pattern.

  • A wide variety of features for web development: URL routing, free API, database migration, etc.

  • Extensive security features

  • An excellent solution for IoT, AI and Machine Learning technologies

  • Flexibility

  • Monolithic structure

  • Weak functionality for multiple simultaneous requests management

























Ardas Experience in Building Scalable Web App [Case Study]

The best example of our expertise in the field of creating scalable web applications is the email template visual builder with AMP support, which is very popular today and is used by companies such as McDonald's, Oracle, Amazon, Airbnb, etc. We still provide full development and support for this SaaS, including business and financial monitoring.

The Task

The main task was to create a product that would be significantly ahead of competing offers from the first days of launch and would be ready for use by a large number of users. That is why we started with an advanced business analysis and developed a very detailed MVP plan. As a result, we determined the web product's main features and target audience.

After planning all the steps to create a scalable web application to the smallest detail, we started working on its scalability and the possibilities of its improvement in the future from the first phase. It was critical because the product has the following features that affect performance:

  • Export of 60 popular ESP systems and email services (Gmail, Hubspot, Mailchimp, Outlook, GetResponse, etc.).
  • AMP support for Gmail, which allows adding real-time dynamic content to emails (custom forms, carousels, interactive banners, etc.).
  • Updating the content of emails in real-time.
  • Gamified interface.
  • Opportunities to collect user feedback.
  • Email sharing, etc.

All these features require huge server capacity and affect the speed of the web application. Not to mention that it is used by more than 500 thousand users today, and this number is constantly growing.


So, we created a team of experienced backend and frontend engineers. The first ones took care of architectural and infrastructural solutions that would not only ensure the app's performance but also leave room for improvements and expansion of functionality in the future. The second ones, together with the designers, thought out the UX and the interface design, which would provide a unique digital experience to users without an additional load on the server side.

We chose the SaaS model because it allowed us to create a secure, high-performance and scalable system capable of meeting the needs of large companies and handling heavy workloads. Before, our team became an offshore part of the customer's company, which continues to develop and improve the product.

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Final Thoughts

Web products' scalability is about their availability, high performance, reliability and future improvement possibilities. It applies to almost all application components, including the backend, frontend, databases, etc.

You can scale software in different ways and within different strategies. For this, it is essential to have a team of experienced engineers who can develop an effective plan for scaling and improving the system.

At Ardas, we have extensive expertise in this area and a large portfolio of successful projects. Our developers possess all the necessary technical skills to build scalable products from scratch and improve the scalability of existing applications. And we will be happy to advise you in this matter, so contact us in any convenient way.

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