Product Manager at Relevant Software

Your Handy Guide to Large-Scale Web Application Development

November 17, 2021

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Consumers want to meet their needs faster, get more information, see brighter pictures, and hear clearer sounds. Your web application’s ability to meet such expectations, as well as its potential to grow in time, depends on its scalability.

This article will help you understand what scalability is, explore large-scale web application development steps, considerations, challenges, and solutions.

What is meant by a large-scale web application?

First of all, let’s start with the basic terms. 

Scalability is the ability of an application to sustain consistent performance, despite how many people use it at the same time. Hence, a large-scale web app is one that can handle high volumes of data and traffic and can adapt to drastic load changes without affecting the quality of operations.

This can be evaluated on:

  • Performance – high-traffic applications can handle a thousand transactions per second or millions of users/requests as effectively as a hundred.
  • Distribution – it uses servers that are geographically closer to users.
  • Data – it can handle large volumes of different data types (e.g., it can handle customers and track their behavior).
  • Availability – it can be accessed at any time of the day or week.

Why does scalability matter?

If you’re looking to develop a complex application, for example, a custom loyalty app, that can support many users at the same time, scalability is essential because:

  • It helps meet market demands – as market expectations change continually, a scalable app will be more apt to cater to customers’ needs and wants. As a result, you’ll be able to maintain a positive user experience when your successful marketing efforts boost user traffic and the number of transactions.
  • The system can handle a higher load – scalability helps adjust to any changes in your business, such as explosive growth in the number of customers or volume of data. This also helps prevent bugs or glitches, thanks to strategic scalability testing, and improve growth potential, ROI, and user feedback.
  • It’s more financially beneficial – if you develop an app that can scale up to a million users right from the start, you don’t need to remake it when the user count skips from 10K to 100K and up to 900K.
  • A scalable app provides a stable workflow 24/7 – it’s less likely to experience crushes during seasonal events, such as Cyber Monday, that project an increase in data usage, app traffic, and, hopefully, transactions.
  • It allows for adjustment to local laws of different countries – some countries don’t allow storing of personal data outside their borders. In this case, the distribution of servers helps abide by such laws.
  • It maintains connection speed in different parts of the world – scalable apps are identified by the distribution of servers across the globe. Servers located in different countries allow sufficient handling of peak response speeds. 

If your web application can run 24/7 in different traffic and workload conditions, ultimately, this positively affects customer experiences and your profit. But is this necessary in every single scenario?

Does your business need a large-scale application?

To answer this question, let’s get into an example. 

Many social media influencers have faced the same problem when hyping up a new product release on their channels. They’ve directed followers to a website, and once the product they are promoting goes online, instead of selling out in 20 minutes, the website crashes under the storm of eager fans. So instead of teasing a restock date, they have had to film an apology video to pacify their customers.

This wouldn’t happen if their web app was ready for the increased load. A scalable app would let customers buy as many items as are in stock, at the same time, without crashing. 

Your product doesn’t necessarily have to lead the hype. It may increase in popularity gradually. But if you expect your business to perform well, your web app should also be high-performing.

On the other hand, if you don’t have valid reasons to think it will grow, like in the case of newly launched start-ups, your app might not need this. Right?

The subsequent sections should help you figure out if your app needs it or not.

Benefits of Large-Scale App Development

How to make scalable applications: Steps, considerations, and design

By now, you might be thinking that any and every application should be scalable from the start. But when you start a new project, there’s no guarantee of success. If you follow the lean software development approach, your main goal is getting a product to market and testing how it performs. Scalability is likely an unnecessary factor at this point.

Scaling the frontend and backend makes sense when you’re sure that your product will find a place on the market and continue to grow. The following stages describe the process of creating scalable apps out of existing web products.

7 steps of designing large-scale applications

Let’s dive straight into the process: identify your scalability needs and choose the right monitoring tools, infrastructure, architecture pattern, database, and framework.

1. Verify the need for scaling and manage expectations

If you already have an app, scaling could be costly. On the other hand, besides the issues with increasing traffic, if you intend to develop features to your system or make the existing ones more complex, the current functionality might not handle the changes.

Make sure that your expectations of scaling justify the expenses. And ensure that you’re not simply jumping on the bandwagon because everyone is talking about scalability.

How do you know if you need to build a large-scale web app? Here are a few questions that can help you decide:

  • Do you expect an increase in users? By how much, and within what time frame – six months, a year?
  • For how long can your customer/user base fit the server(s) you currently use?
  • What storage plan do you use? Is it flexible for size changes?
  • What options do you have in case you experience a drastic increase in user and data traffic?

2. Apply metrics to define your scalability challenges

After careful consideration, you decide that your application needs to be scaled. The next step is to decide what scalability issues you need to focus on. This can be done by tracking the following metrics:

  • Use of CPU. This is a basic and essential metric that can be measured by most app-monitoring tools. High CPU usage suggests that your app is already experiencing performance issues.
  • Use of memory. This is calculated per each process that happens in your app and then aggregated into a single execution.
  • Network Input/Output. This is the time spent on sending data from one tracked process to another. Look for instances that consume the most time.
  • Disk Input/Output. This is all the operations that happen on a physical disk. And it’s another process attributed to time—while your app is reading data from a file, the CPU is on standby.

3. Choose tools for evaluating metrics and further monitor scalability

To find problematic areas, you need app-monitoring tools to track related metrics. Some examples are AppDynamics, Stackify Retrace, and New Relic AMP.

Once you choose a tracking tool, perform tests for the above-mentioned metrics. If any of them show high results, you need to dig deeper into the problem and create test cases to scale your app.

These initial results are your benchmarks. Hold onto the tool you choose to keep tracking the metrics during and after developing a large-scale app.

If you use a PaaS, such as Amazon Web Service, Heroku, IBM Cloud, or Microsoft Azure, they have built-in monitoring tools. On this note:

4. Choose the right infrastructure options for scalability

Using a PaaS for a web app is recommended because cloud services take care of many aspects involved in web app development and maintenance. These aspects include the infrastructure and storage, servers, networking, databases, middleware, and runtime environment.

PaaS can make scaling easier since they offer auto-scaling, along with reliability and availability of SLAs.

If you don’t yet use a PaaS, consider AWS, Heroku, IBM Cloud, or MS Azure.

5. Choose an architecture pattern that will suit your app’s scalability

Choosing the right architecture pattern matters because some features of your app will depend on its scalability, while others will be essential only for certain users or at certain times and could be bundled as plugins.

The top four most used architecture patterns are:

1) Layered architecture

The name is pretty self-explanatory since apps with this architecture are built in layers. Each layer has its task, and data has to travel through each from top to bottom, where there’s usually a database.

This type is most suitable for:

  • new apps with a limited time frame,
  • apps that require strict standards in maintenance and testing,
  • developer teams that don’t have much experience or understanding of different architectures, and
  • enterprises that mirror traditional IT department processes.

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2) Event-driven architecture

Unlike in the layered architecture, this type consists of a central unit and modules that interact with data that’s particular to them. When an event triggers the central unit, it delegates the data to a module that’s dedicated to the data type. 

Event-driven architecture is most suitable for:

  • developing asynchronous systems, and
  • user interfaces.

3) Microkernel architecture

This type consists of a core system and plug-in modules that offer additional features and specialized processing to enhance the core functionality. A simple example of such architecture would be WordPress.

This type is most suitable for:

  • apps that have a wide target audience,
  • instances where you can clearly distinguish between basic and higher needs, and
  • instances where you can distinguish between core and dynamic routines.

4) Microservices architecture

This is high-performance web application architecture that helps build flexible applications by making it a distributed system that loosely connects to individual web services via lightweight protocols.

With the microservices approach, you can develop, test, and deploy individual services without affecting the whole app.

Microservices architecture is most suitable:

  • when different tasks can be separated and don’t affect each other,
  • for websites with small components,
  • for rapidly growing applications, and
  • when hiring a software development team that is distributed across different countries.

6. Choose the right database to scale

The kind of database you choose will depend on the data types you need to store – relational or disconnected. In the first case, you will need a relational database, such as MySQL or PostgreSQL. For the latter, you’ll need a NoSQL database, like MongoDB.

Any database you choose should be easy to integrate into your app.

7. Choose a scalable application framework

Application frameworks support graphical user interfaces and web-based application development. For example, they allow sharing of code for different modules, reducing developmental issues.

How to Design a Large-Scale App: Сhecklist

The success of your efforts to scale your web app will depend on how well you choose the infrastructure and architecture pattern to support a large scale.

How to make a scalable web application: 4 things to consider

Aside from the tools and patterns, there are a few more aspects of large-scale development that we recommend you take into account and implement:

  • Architecture. We already touched on the matter of patterns, but high-traffic web app architecture also involves techniques that ensure application build. While patterns constitute the design part, when it comes to web application development, you need to choose the programming language, framework, APIs, and integrations that are most fitting for the goals of your application.
  • TDD (Test-Driven Development). TDD is an approach to developing applications when your software requirements are turned into test cases. This approach makes sense in scalable development because you already have cases for testing – the scalability issues you determined using metrics.
  • CI (Continuous Integration). This is a DevOps practice that allows continuously integrating code changes. It’s most useful when a project requires timely results and has multiple contributors.
  • Security. No web app is fully secure, but certain practices help improve security against hackers:
    • Hashing and salting databases where passwords are stored so people who have access to them can’t get the passwords.
    • Securing client-server communication with a JSON Web Token (JWT).
    • Setting expiry on session cookies where the JWT is stored.

After choosing all the tools and technology, and setting up appropriate processes, you can progress to designing your large-scale app.

Scalable web app architecture: How to design one

When designing scalable web app architecture, another thing to decide is whether you’re scaling up or out:

  • Up-scaling is called vertical scaling and it means adding more resources to existing systems; for example, increasing the capacity of an app with more memory.
  • Out-scaling is called horizontal scaling and it means creating a distributed architecture; for example, increasing the capacity of an app with more nodes.

Horizontal scaling is a better option for most purposes as it is easier to implement, cheaper to do, and results in better performance. Especially considering the growing popularity of using cloud databases in web app development.

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Components of web app architecture design

There are a few components that allow large-scale application design to work: 

  • Cloud storage. This is useful because you can adjust the storage capacity according to your application’s stage, so you pay for what you use. You can find both relational and NoSQL cloud databases.
  • Distributed cache structure. You need nodes that cache data so it can be accessed more easily when it’s needed again.
  • Microservices. These are loosely connected components of an app that can be scaled individually.

Why is microservice architecture the right option when scalability is required?

We’ve mentioned microservices in web app architecture quite a bit through this guide. That’s because microservices architecture is the better option in terms of scalability. It ensures:

  • Fault isolation. Since the system isn’t a monolith and you can perform work on microservices individually, failures won’t affect the entire app, only the individual component.
  • No ties with a single tech stack. Another advantage of having loosely connected components is that you can use different technology stacks, if needed.
  • Added simplicity. Microservices architecture allows clearer understanding of the service functionality when you hire remote developers.
  • High speed of deployment. You can deploy changes faster because of the smaller work area.
Major Advantages of Microservice Architecture

What are the challenges of building scalable systems?

Whether you’re building an app from scratch or scaling an existing application, there are certain challenges you should be ready to meet and consider at the planning stage:

  • In-house costs. The systems used to manage the large-scale app might end up way out of your current budget.
  • Time expenses. It could take a lot of time to manage the cost, and before that, to research what exactly your app requires.
  • Lack of necessary hardware or experience. What could also turn out to be a problem is installing new servers and acquiring expertise in data center management.

What is the solution to these challenges?

A better solution than doing everything on your own is hiring an expert in scaling applications, or for high-performance web development, who will help you reach your business goals in the best possible way. For that, Relevant Software has:

  • A pool of talented professionals – 85% of the tech team are Middle and Senior Engineers.
  • Eight years of successful experience – we have delivered more than 200 projects remotely.
  • Worldwide recognition – our clients are from the UK, Germany, Norway, the US, and other countries across the globe.

Leave your inquiry below to find out how to better develop your new scalable web app: 

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Scalability is essential for successful web applications to meet growing market demands. If you want your business to succeed, your applications should be developed with scalability in mind. However, you can evaluate existing apps against scalability and improve them based on the issues you find.

Is large-scale web application development the best option for you?

There are a few challenges involved in building such apps. For example, the costs for hardware and software required to scale an app. It also requires expertise that your team might not have.

You can beat these challenges by hiring a team that has extensive experience in custom web development – Relevant Software. Here you will get:

  • Full-stack website application development – we take care of frontend and backend web development and also produce fast single-page apps.
  • Proper technologies – we use technologies that ensure the reliability and security of web applications, such as React, Angular, PHP, Python, Java, MySQL, and Oracle.
  • A dedicated team – a well-formed team of developers who can fulfill your project objectives.

Contact us for more details.


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Product Manager at Relevant Software
For more than 6 years, I've been working as Business Analyst and Product Manager at Relevant. I'm responsible for requirements engineering and management and solution implementation control.

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