Web App Architecture: Principles & Guidelines

The BBC once noticed that they lose an additional 10% of users for every extra second it takes for its site to load. For the website that offers online content to over 100 million devices, coping with high loads is critical. The way out for BBC was to build scalable web applications. 

We talk a lot about the complexities of building web applications, but we should also mind building scalable web applications that can withstand usage peaks. 

In this article, I'll explain what it takes to build a scalable web application ready for high loads and share some principles and guidelines for building scalable software systems.

What Is Scalable Web Architecture in Simple Words

I like to compare web architecture to a lego city. It also consists of small elements that can form into bigger parts. In web architectures, these elements are called: 

  • Modules
  • Components

Web app architecture components and modules interact differently, and the way you can use them also varies. The goal of scalable web architecture is to set the communication boundaries between these elements to make the app reliable. 

build scalable web applications

Let's say you need to build a wall in your lego house, and some bricks don't suit initially. So you should modify them: make them longer, wider, etc. Only then connect one brick with another and have a strong wall. 

Setting the rules and modifying elements to make the app work smoothly is what a scalable application design stands for. 

How Web Architecture Works

Now that you know what scalable web architecture is, let's figure out how it works. All applications are made up of two primary components: 

  • Client-side, popularly called the frontend. It's where user interaction takes place.
  • Server-side, also known as the backend. This part is treated by developers only. 

Apart from this, another component – the database server that sends the requested data to the server-side. Ok, now, since that's clear, here's what happens when you type a request in Google and hit enter.

  1. The browser sends your request to the Domain Name Server that will recognize the IP address;
  2. The server catches the request and sends it to the data storage;
  3. The server sends a response with requested data back to the browser; 
  4. The page is then displayed on your screen with the requested information.
build scalable web applications

You probably have never thought of what happens for that 1 - 2 seconds when you hit enter, but this is how it works. So now, let's find out why scalable architecture is important and what happens if you don't build one. 

Why Is Scalable Web Architecture Important?

Spoiler, not all applications should be scalable. 

We at Uptech always ask "why?" before jumping right into "how to build scalable web applications?" So if you come to us with a B2C product, that will probably grow fast. The number of users and services will increase significantly – then chances are we'll advise building scalable web applications and add it to the technical requirements. Simply because your product requires scalable architecture. In the case of B2B products, scaling isn’t the top priority because there is usually less data to process. 

build scalable web applications

Scalable web architecture helps you understand what and where is located in your app, which saves up time later. Below I list 5 key reasons why building scalable web applications is important. But note, getting maximum benefits requires a great effort right on the start line of the development process.

build scalable web applications

Smooth app performance

Creating an app to sell to 10-20K users is a rare case. Most businesses aim to have user acquisition in hundreds of thousands of users in the first year. Consequently, building an app that is not scalable is an intention for having technical debt very soon. 

Web services scalability makes your app perform and operate well no matter how many people use it, 100 or 100,000. That's simple. 

Easy integration of new features

While developing, I often ask myself: how might I build an app that not only works without bugs but also is easy to modify? At this point, I start to think of how I can make these lego bricks universal, which means I can effortlessly plug new pieces of functionality into them. 

For you as a business owner, it means less time and money spent on integrating new services and features. And building scalable web applications comes to the rescue here. 


Well-thought scalable web architectures can handle the various loads and adapt to new business requirements skillfully. So you spend less money on updating the site, integrating new functionality, etc.

Reduced development time

Changing the code structure takes lots of time, especially when it's poorly written. However, in a scalable web application, developers can divide the structure into several small modules, eventually reducing the development time as well. 

Furthermore, it becomes easier to integrate new features and services without affecting the overall structure — win-win for developers and business owners. 

High security

Security in scalable web services is mainly about limiting the attack surface. What do I mean here? Let's say you have a scalable web architecture and your friend lacks one. 

You implemented proper security mechanisms and carefully managed access and data. With bad architecture, your friend has little control over security because data moves across the application unpredictable.

build scalable web applications

In case of a cybercriminals attack, your friend is at the risk zone. Having scalable web architecture saves you from losing data or blocking access to certain services. Scalable server architecture gives you extra protection from such cyber-attacks, and that advantage can't be overrated. 

Ways of Web Application Scaling

So what to do when your servers cannot cope with the number of requests coming in and out? There are 2 ways of scaling web applications you can use: 

Vertical scaling

When I say vertical scaling, I mean improving the performance of the system by adding bigger machines. 

For example, you're not satisfied with the speed of data processing in your app. To fix this, you simply replace your server with a more powerful one. Instead of using a 4GB server memory with 2 processors, you take the one with 8GB memory and 4 processors. 

Vertical scaling is the easiest scaling approach since it doesn't require any changes to the application programs running on such systems.

Horizontal scaling

Horizontal scaling is when you improve the performance of the system by adding more machines. 

In this case, you have a 2GB server with 2 processors and add an extra one with the same characteristics. Now, you have two servers that execute the same function simultaneously. The result is the same – your system performs better and faster. 

This scaling approach is a bit tricky because it requires a load balancing element because requests have to be directed to different machines and they should have the same logic and rules not to conflict with each other.  

It’s hard to say what way of scaling suits you best because everything depends on your specific product, time-to-market, and potential growth plan. So mind it while developing or contact us. We’ll be happy to consult you on that topic. 

build scalable web applications

How to Scale a Web Application: Uptech Flow

Our approach at Uptech is to build apps that people can use right away. Scaling web applications plays a significant role here because it speeds up the time-to-market, so people literally can use your app right away. 

To keep scaling organized, we have a step-by-step guide on how to scale a web application. Check it out.

how to build scalable web applications

Step 1 – Define the bottleneck

First, we define the problem. Whether it is a slow page load time or a high number of errors? We mark it as a bottleneck and see if we can fix it by web scaling. 

Step 2 – Scale

If the scalable design is what can help here, we pick one of two scaling ways I described above and start scaling. 

Step 3 – Look what changed

Scaling web applications is pointless if you don't set the metrics you want to improve. That's why the important step is to set the indicators you wish to improve and compare them before and after scaling. 

If the bottleneck was slow page load time, check how it changed. 

build scalable web applications


Our job here is not to put as much as possible in your app. We step back and help you figure out whether your product actually needs scaling. Only then we jump into it. 

Web Application Scalability Principles

Since we're approaching the finish line, here're 3 principles you should keep in mind from the moment when you just decided to build scalable web applications. 

build scalable web applications

The app performs smoothly

So make sure your app works without delays and crashes. 47% of users expect a maximum of 2 seconds loading time for an average website. People don't like to wait, so don't give them a chance to just leave your app, especially if you can fix the problem.  

The app is available

Availability is fundamental. If you need your product to be available 24/7, design it in a scalable way that allows the system to be up and running quickly in case of any failure. 

The app is easy to update

Your product has to be easy to operate and update. Scalable code is the one that can be maintained by ever-changing sets of eyes, deployed on changing platforms, and clear so that a developer can open it years later and get it.

web app architecture consultation

Summing Up

When it comes to app performance, scalable web architecture is what matters. At the simplest level, the goal of scalable web architecture is to make the app work smoothly. 

There are 2 main ways of scaling. You should choose the one based on your product, time-to-market, and potential growth plan. The main benefits of scalable web architectures are executing more work and sustaining high load performance without experiencing downtime responding. 

Note that not every app should be scalable. But every scalable app requires a team of professionals. We at Uptech have 5+ years of developing apps for startups worldwide. So if you need help with designing a scalable web architecture or not sure whether you need one, drop us a line. We'll be happy to help you! 


Let’s build your next product! Share your idea or request a free consultation from us.

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