What Is Software Scalability and Why Is It Important for App Development?

In 2023, over 3.7 million apps were available on the Google Play Store, and approximately 1.8 million apps were available on the Apple App Store.

All entrepreneurs aspire for their mobile applications to become a commercial success. As the app becomes more successful, its user base steadily expands, directly related to increased demand for its functionality.

The more users use the program, the more data is exchanged, more backend operations are active, and more storage space is required to hold all that data. A crash is guaranteed when the app is not scalable enough to handle all this data.

Have you heard of Disney's Applause app? The app was designed for viewers to engage with various Disney programs. The app was quite well-liked but not very scalable.

A high volume of fans was too much for it to handle, which made for a bad user experience. People were so annoyed that they left negative reviews. The app was never able to bounce back from this bad reputation.

Irrespective of sector or preferred tech expert, a business owner must know the significance of software scalability. In this article, you will learn the different aspects of software scalability, why it is important, and how to achieve scalability in software.

This article will cover the following details:

• What is scalability in software development and why is it important?
• Types of software scalability with benefits and limitations
• How to build scalable software?
• Challenges of software scalability and how to overcome them
• Scalability and agile - advantages and future trends
• What is modular architecture and how can it help in scalability?

What Is Software Scalability, and Why Is It Important For Your Application?

According to Gartner, scalability is the capacity of a system to reduce or enhance performance and cost in response to changes in processing needs. Scalability is an application's capacity to handle workload volatility while adding or deleting users with low software development expenses.

As a result, a scalable system is intended to stay stable and function well with a significant increase in workload, whether foreseen or unexpected.

No matter how well-thought-out the concept of an app is, it won't get very far without a strategy for future expansion.

A business owner is in danger of not being able to satisfy the demands and expectations of an expanding user base, which might lead to its failure on the market.

That's exactly why scalability should be a priority from the very first stages of the project development.

Agile methodology is considered the best way of building scalable software solutions. It can help teams (in-house or third-party) adopt an evolving landscape while focusing on efficiently delivering business value.

Companies using agile methodology for software development are confident that their product is high-quality because testing has been performed throughout the testing development process. Even third-party software development companies ensure proper testing when using agile practices.

Adapting to change is considered an additional expense by the traditional software systems development process. However, agile has eliminated this idea by introducing short iterations in the agile cycle, allowing changes to be made easily and quickly, helping the development team modify the process to fit the client's needs better rather than the other way around.

Scalability is best achieved with Agile because one of the core principles of the Agile Manifesto is to Satisfy customers through early and continuous delivery of valuable work.

What Are the Types of Software Scalability?

An app can be scaled either Horizontally or Vertically. Here are the details for each strategy with their respective advantages and disadvantages.

Horizontal Software Scalability (scaling out)

You can expand software horizontally by introducing extra nodes into the system to accommodate a bigger load because it will be dispersed across the machines in the network.

For example, if an application begins to experience delays, you can scale it out by adding another server.

Horizontal scalability is preferable when you don't know how much load the application will need to manage in the future. It's also a good choice for applications that have to expand quickly with no downtime.

Advantages:

• Resistance to setbacks. Other nodes will take over if one fails.
• Since there is no need to turn off current nodes to add new ones, there is no downtime when scaling.
• In theory, there are countless ways to scale horizontally.

Limitations:

• Additional complexity. You must ascertain how the workload is split across the nodes. Load management is possible using Kubernetes.
• Increased expenses. The cost of adding new nodes is higher than the maintenance costs of existing nodes.
• There's a chance that node connection speed will limit the overall program speed.

Vertical Software Scalability (scaling up)

The goal of vertical scaling is to increase the hardware's power of the existing system.

In this strategy, a business owner scales the application by upgrading the existing server by increasing its RAM, processing speed, and other specifications.

An alternative would be disconnecting the outdated server and replacing it with a more sophisticated and powerful one.

Benefits:

• To adjust to the upgraded infrastructure, there is no need to modify the logic or configuration of an application.
• Reduced cost because the cost of upgrading the existing server is less than adding a new one.

Limitations:

• There is some downtime during the upgrade process.
• The improved machine still has a single point of failure.
• There is a limit to how much you can improve one device.

Horizontal Scaling vs. Vertical Scaling

Here is a comparison that gives an overview of different aspects of both software scalability types.

• Description

Horizontal scalability: Adding more nodes to the system.

Vertical scalability: Enhancing the capabilities of the existing node or replacing it.

• Workload distribution

Horizontal scalability: Distributed across the existing and newly added devices.

Vertical scalability: A single node handles the workload.

• Concurrency

Horizontal scalability: Multiple machines work together.

Vertical scalability: Multi-threading on one device.

• Data management

Horizontal scalability: Data is divided across the connected nodes.

Vertical scalability: All the data resides on a single  node.

• Downtime during scaling

Horizontal scalability: No.

Vertical scalability: Yes.

• Load balancing after scaling

Horizontal scalability: There is a need to change the configuration to allow for load balancing

Vertical scalability: Not required.

• Failure resistance

Horizontal scalability: High. There is no single point of failure.

Vertical scalability: There is a single point of failure.

• Initial investment

Horizontal scalability: Higher.

Vertical scalability: Lower.

• Limiting factors

Horizontal scalability: Theoretically unlimited.

Vertical scalability: Limited by what one device can do.

How to Build Scalable Software - 8 Tips

Scalability should be part of the application development process from the beginning of the business model plan. When application architects design a plan, they should consider the future of the application with scalability in mind and plan its growth.

To build a scalable app, follow these eight best industry practices and scalability testing techniques. These eight recommendations are categorized into several stages of the software development process:

Tip # 1: Choose cloud hosting for better software scalability

An app can be hosted in two ways: on-site or in the cloud. One of a mix of both ways can be selected to host an app.

By selecting cloud computing services, an app is not utilizing business infrastructure but instead uses third-party resources. Without spending money on servers and other hardware, a business owner has infinite flexibility when scaling up and down using the cloud.

The upkeep and security of the infrastructure are also cloud providers' responsibility. It is especially a good idea to use cloud hosting for healthcare apps.

Tip # 2: Use load balancing

If you opt to extend horizontally, you must implement load-balancing software to spread incoming requests across all devices capable of processing them and ensure that no server is overburdened.

If one server fails, a load balancer will shift the server's traffic to other online servers that can handle these requests.

When a new node is joined, it instantly becomes a part of the setup and begins accepting requests.

Tip # 3: Cache as much as you can

Cache as much data as possible to relieve the strain on the database. Configure processing logic so that it rarely changes but often read data can still be obtained from a distributed cache.

This will be more efficient and less expensive than searching the database with each request.

In addition, if something is not cached but is often visited, the program will fetch it and cache the results.

Tip #4: Enable access through APIs

End customers will access products through several clients, so providing an application programming interface (API) that everyone can use to connect will be easier.

An API functions as a bridge that connects two apps. Account for various client types, such as smartphones, desktop apps, etc.

Tip #5: Choose asynchronous processing

An asynchronous process can carry out activities in the background. The customer does not have to wait for the findings and can begin working on anything else. This approach provides software scalability by allowing programs to execute more threads, allowing nodes to be more scalable and manage greater load.

If a time-consuming job arrives, it will not stop the execution threat, and the program can still perform other tasks concurrently.

Asynchronous processing power is accomplished at the code and infrastructure levels, whereas asynchronous request handling is accomplished at the code level.

Tip #6: Select database types that are easier to scale

Some databases scale more easily than others. NoSQL databases, such as MongoDB, are, for example, more scalable than SQL. As previously noted, MongoDB is an open-source database commonly used for real-time large data processing. Amazon DynamoDB and Google Bigtable are two more NoSQL alternatives.

SQL scales well in reading operations, but if these concepts aren't important, you can use NoSQL for better scaling.

Tip #7: Consider microservices over monolith architecture

Monolithic architecture: Monolithic software is created as a single entity that combines client-side and server-side functions, a database, and so on.

Scaling monolithic software is feasible but must be done comprehensively using the vertical scaling strategy, which is costly and inefficient. One must rebuild and redeploy the complete application to upgrade a single component.

So, if the solution is simple and will only be utilized by a few individuals, go with a monolithic.

Microservices architecture: Microservices are more adaptable than monolithic systems. This application comprises multiple components that operate together but are deployed individually. Microservice application components can easily be scaled individually without putting the internal software as a whole under strain.

So, microservices are the way to go if you need a scalable solution. One of the numerous benefits of this design is its high software scalability.

Tip #8: Monitor performance on a timely basis to Scale

Once a program is deployed, it needs to be monitored to see any early indicators of performance deterioration that can be fixed with scaling.

During the development process, one must incorporate a telemetry monitoring system into the program to detect problems with software scalability testing. With the help of this system, the app can be monitored:

• Average response time
• Throughput, which is the number of requests processed at a given time
• The number of concurrent users
• Database performance metrics, such as query response time
• Resource utilization, such as CPU, memory usage, GPU
• Error rates
• Cost per user

You can benefit from existing monitoring scalable solutions and log aggregation frameworks.

How Do You Prepare Your Application for Growth? - Principles of Scalability

Scalability requires preparation and planning because each company has unique requirements and goals. A CTO must explore objectives, resources, appropriate technology, and an effective testing plan before going under the development process.

Here are some important factors to consider for preparing the application for future growth:

Business Objectives

Businesses must clearly define the app's goals before developing it. For instance, it's possible that the company operates in a specialized industry or digital product is intended for a particular customer base and won't be sold in all app stores.

Instead of becoming the best application on the market in this scenario, the primary goal can be to automate and streamline the procedures inside the organization. These goals influence the degree of scalability that applications must have to continue operating over the long haul.

The Right Technologies

Considering scalability in the planning phase, you'll be ahead. It's crucial to give the chosen technology extra thought before developing the app.

The degree of scalability varies across many technologies, including databases, frameworks, and programming languages.

For instance, Node.js is the preferred backend environment for scalability and flexibility, and it can be utilized for both mobile and online applications.

Build Functionalities for Future Growth

Businesses don't have to focus on making software with many features in the initial version. Still, it would be beneficial if you built it with future development and extension in mind.

A program can only handle a small number of users initially and only stores and executes a few commands. Then, to make the same program scalable, it must be built with expansion in mind. This will make managing expansion, including database and speed expansion, easier.

Write Clean Code

Writing clean code is crucial when developing enterprise software for growth. To build scalable and maintainable code, one must employ programming approaches such as  KISS (keep it simple, stupid), DRY (don't repeat yourself), and others. You will also prevent needless enterprise software performance iterations.

A well-written code makes it easy to apply future updates. A new programmer will devote less effort to analyzing current scripts and more to developing new ones.

This emphasizes the need to hire a good developer who will not only do the assignment but will also do it properly.

Use the Caching Technique to Improve Scalability

Caching keeps pre-computed results that applications can retrieve without needing database queries or page views. Computing power up your system to avoid repeatedly handling costly requests, lowering total response time and program performance.

This implies that software only makes one request, caches the data, and then keeps using it. The program will have to search the cache for the data before making a request, which helps consumers owing to the speed of software even as it scales.

Asynchronous Processing

It describes procedures broken down into independent phases that can be processed without waiting for the completion of the preceding one.

For instance, the user can receive a "sent!" indication even when the email is still technically being processed.

Bottlenecks impact large-scale software performance; some are eliminated through asynchronous processing.

Scalability Challenges and How to Overcome Them

Although an application's capacity to scale is essential to its success, scaling can also provide several obstacles that must be removed. This segment will discuss some of the most prevalent scaling issues and offer solutions.

Performance Issues

When scalable systems need to manage growing workloads effectively, performance problems can be a significant concern. Monitoring application performance frequently, identifying bottlenecks, and implementing speed-enhancing strategies like caching and optimization are critical to resolving performance concerns.

Infrastructure Limitations

Infrastructure constraints can also be a problem for scalable systems, which must be able to manage rising workloads effectively.

Overcoming infrastructure constraints may be essential to improving or replacing existing infrastructure or embracing a cloud-based infrastructure with better scalability. Backendless Cloud infrastructure, for example, is designed to grow automatically to match your application's demands.

Data Management Challenges

Data management can also be an issue for scaled applications since the program must handle increasing volumes of data efficiently.

Employing data splitting or sharding techniques or using a NoSQL database more suited for scalability (albeit not without drawbacks) may be essential to tackle data management issues.

Furthermore, monitoring data expansion regularly and making necessary changes to the data architecture is critical.

Increased Costs

When a business expands its operations, the expenses increase significantly. As you expand the infrastructure, you invest more money in hardware, software, and personnel.

An easy option to tackle this difficulty is to employ a cloud-based solution to help you save money. Working on finance and accounting in advance is also beneficial for thoroughly comprehending the budget.

Changes in the Marketplace

Businesses can be successful when they adjust to changing market conditions. New rivals, new technology, or changes in client demand are examples. Develop a flexible corporate infrastructure to swiftly react to changes to address this difficulty.

Additionally, employing the appropriate technology might help you scale rapidly and efficiently.

Can Modular Software Architecture Improve Software Scalability?

A software system that is designed using modular software architecture comprises separate, replaceable modules that connect via well-defined interfaces. The principle asserts that each module should have a single responsibility and minimum dependencies on other modules, which can be achieved with the aid of this method.

Yes, Modular software architecture can improve a software system's scalability, maintainability, and quality.

You can reduce code complexity, and improve components' coherence and reusability by breaking the system into smaller, more manageable modules.

Also, it can independently test, debug, and implement modules, which can shorten the time it takes to design a new product and lower the possibility of mistakes.

Furthermore, it can simply expand and modify the system by adding, deleting, or swapping out modules without impacting the system as a whole.

It is a good practice to use modular software architecture in SaaS software development.

Is It Possible to Build a Scalable Architecture in an Agile World?

Agile methods are standard in the field of software development today. However, most development teams are left to use conventional architectural techniques on agile projects, which might not be effective in real-world scenarios. Architecting is a slow process that calls for revision, criticism, and adaptation. Businesses can not expect amazing software to be produced overnight.

Companies that are well-known for their adaptable microservices architectural paradigm include Uber and Spotify. These architectures, in the meantime, are not pre-designed. Rather, they are progressively built via a dynamic, forward-thinking process.

Scalable architecture offers the adaptability needed to meet demand and development in the future. Building a scalable architecture requires defining design principles with business goals in mind, defining only a high-level initial architecture model, using cloud-native solutions, building software in a modular fashion, keeping an eye on usage and performance, and reviewing and adjusting the architecture regularly.

Domain-Oriented Microservices Architecture, integrated with event-driven architecture, CQRS, BFF, APIs, and Agile practices, offers a powerful approach for organizations to build adaptable, scalable, and business-aligned software solutions.

By leveraging these principles and frameworks, organizations can unlock the full potential of their architecture, deliver exceptional value to customers, and achieve sustainable success in today's fast-paced digital landscape.

Example # 1 - Cisco

Cisco adopted the Scaled Agile Framework (SAFe) and introduced three Agile release trains on the Subscription Billing Platform.

These include capabilities, defects and fixes, and projects. The idea was to collaborate on building and testing small features within one SaaS component and delivering them to the system integration and testing team.

Cisco delivered the new release of its subscription billing platform on schedule. In the new release, defects were reduced by 40% compared to previous releases, and efficiency increased by 14% thanks to agile methodology.

Example # 2 - Fitbit

Fitbit successfully used Scrum to meet an urgent consumer holiday-driven product delivery schedule. However, as the company and customer base grew, it became clear that the company would need to scale its process.

The company started with 12 Scrum teams at its initial Program Increment (PI) planning event, slowly adding more units and functional groups with each successive PI. The company immediately saw increased velocity, cadence, and team engagement.

The year after deploying its agile methodology, Fitbit released four new products and shipped millions of devices thanks to its successful scaling effort.

Summary

A scalable application means you gain more flexibility, security, and possibilities for additional functionalities. Scalability should be the first thing in the minds of business owners, especially when creating a software development project.

Software scaling depends on selecting the required skills, expertise, tech stack, and detailed strategic planning.

By focusing on the right selection of scalability type, horizontal or vertical scaling, implementing the right technologies such as caching, testing, and application security, businesses can build scalable software solutions to meet the needs of an ever-growing customer base. This approach helps businesses to deliver a high-quality user experience and maintain optimal performance.

In this blog, we have covered everything that you need to learn about what scalability is, how it’s ensured, and what benefits it can bring business-wise.