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How to Build a Scalable App — The Ultimate Guide

Web Factory September 17, 2021
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One of the most critical factors for the performance of a web application is scalability. The overall power of any system, operation, or infrastructure to manage the increasing volume of work can be described as scalability. Scalability is also a mechanism that enables a system to manage the increasing ability to expand and facilitate its growth.


When we visit the website or the app of a specific company, we usually form an opinion just about the design. We don’t think about the background mechanisms and never wonder what makes these pages or apps so efficient. However, if we ignore this when building an app, we’ll encounter some of the following problems:


  • poor app performance when a large number of users is using it,
  • extended loading time when we add more products to our portfolio, and
  • common failures and errors when we introduce a new feature.

To prevent these issues when creating a new app, we have to think about building a scalable app. If you design an app that supports scalability initially, you won’t have a problem when you add new features or when more users join your app.

Developing a scalable app doesn’t refer to some kind of special development process. It actually represents a set of standards and methods you should follow to create a high-quality app. This app should provide an outstanding user experience, short loading time, extended product life cycle, and eventually contribute positively to your overall brand image.

These are some factors to have in mind when designing a scalable app: 

Scalable architecture


To make the app scalable, it’s recommended that you apply multi-tier instead of single-tier architecture. The multi-tier model consists of three components—the client, the app server, and the database server. Only the most essential functions should be handled by each layer, thereby significantly enhancing efficiency and scalability. The goal is to simplify and integrate client software and unburden the database server from tasks it shouldn’t run.


This architecture allocates the processing modules more constructively, carrying them out on one or several different servers. These program modules execute application operations for user interfaces and the client for database servers. In addition, to divide the system more precisely into blocks with distinct functions, various application servers may communicate with each other.


As for scaling up or scaling out, we recommend horizontal over vertical scaling. While vertical scaling refers to including more power to the existing machine, horizontal scaling separates the system into smaller components to increase the number of servers that can do the same tasks simultaneously. This improves the overall system performance by adding new servers and processors.


Finally, when it comes to frameworks, some of the most popular ones for scalable apps include Node.js, Ruby on Rails, Django, .NET, LAMP, Laravel, Angular JS, MEAN, and many others.

Cloud storage

Using cloud storage is crucial to building a scalable app. For businesses that require data storage, cloud storage may be a perfect alternative. This is also one of the options where an organisation can continuously extend. If a company wants additional storage capacity, it can purchase it from its cloud storage provider. Finally, this alternative requires minimal upfront investments, indicating that the company can pay when they choose to.


Caching is a way of storing information where servers store pre-computed results. It is a high-speed digital storage layer that stores transient information, allowing the system to respond to data requests more effectively.

If an organisation doesn’t need data at the moment but would need it for later, caching may be a perfect option. This model guarantees that the company can free up needed space when necessary without deleting anything valuable. In the application, caches can often be used at multiple levels:


  • on the requesting node, making the data recovery for your users almost instantaneous, and each node has its own cache,
  • global cache for the nodes, and
  • a distributed cache that can spread the cache across all nodes.


At the speed of light, specialised in-memory libraries like Redis can read and write. In cases of overload, saving some of your data in stores like Redis will help you maintain your app’s scalability.



When it comes to scalability, the proxy’s most significant benefit is synchronisation with multiple server requests. The numerous similar requests can be collapsed into one, and the questions can be limited to the database’s storage. Therefore, both the response time and the output of the database are growing.


When using proxies, the best approach is to integrate them with caches. In such a scenario, their utilisation is considered to be at the highest level.



The process for submitting and processing requests can become slower as the development of the application advances. The need to monitor simultaneous requests and manage a vast number of them will also come up.


That’s why it’s helpful to run specific queries sequentially and to queue them. This strategy enables a client to make a request, receive confirmation, and then go on to other tasks, checking back regularly. Typically, the client would have to wait for the request processing without the possibility of doing any other work at the same time.




Scalability is an integral aspect of a high-quality application. In the future, if you intend to grow your organisation and expand, you need to take care of the scaling upfront. Scalability helps minimise request delay, the release time for updates, and the frequency of errors . What is more, it can reduce the price of development, boost UX, raise revenue, and establish a solid brand-customer relationship.


In general, designing scalable applications is not a distinct form of development but rather a handful of concepts that should be addressed during the development process. If you want to develop a scalable app, contact our team of tech experts.