Scalable Applications: Why They Matter And How To Build Them

scalable app mockup

Growing your business, gaining more traffic, reaching significant milestones — it’s all exciting. But what if your app buckles under a surge of new users?

Slow loading times and frequent crashes drive customers away, tarnishing your brand’s image and hampering expansion. This is why building a scalable application is critical if you’re serious about growth.

In fact, scalability is on Gartner’s list of top strategic technology trends. And it’s not just for enterprises. Around 74% of SMB tech leaders prioritize scalability when evaluating new technologies.

What exactly is application scalability? In this blog, we talk about everything you need to know — what it is, why it’s important, and how to start.

In this blog:

Application scalability definition

Designed for growth, a scalable application can effectively handle increasing users, transactions, and data volume without performance issues.

Scalability maintains (or even improves) an app’s loading speed, response time, uptime, and reliability as loads increase. The goal is to deliver consistently excellent functionality, whether serving 20 users or 20 million.

Zoom is a great poster child for scalability. The video conferencing app’s daily users soared from 10 million in December 2019 to a staggering 200 million by March 2020 because of global lockdowns.

Despite this unexpected growth, it maintained almost disruption-free services. How? By using a global hybrid cloud network that combined its own data centers with AWS scalability solutions and Oracle cloud resources.

Zoom’s exponential revenue hike — from $623 million in 2020 to $4.10 billion in 2022 — underscores scalability’s sheer impact on growth. The company expects to earn $4.55 billion in 2023. 

Vertical vs. Horizontal scaling

There are two types of scaling: vertical (scaling up) and horizontal (scaling out). They both bolster infrastructure with more computing resources but are fundamentally different. While horizontal scaling adds more machines, vertical scaling turbocharges existing machines.

  • Horizontal scaling is like adding more lanes to a highway to manage increased traffic. For example, if your server is maxed out and can’t handle additional stress, you can bring in extra servers to keep things running smoothly.
  • Vertical scaling is like upgrading your car’s engine to make it more powerful. Instead of adding more servers, you improve your current one.

The right choice depends on your app’s nature and expected server load increase, among other factors.

Why is application scaling important? What are its advantages?

Scalable architecture positions your app for success. Here are some of its key benefits:

  1. Savings

Scalable apps use resources optimally. They can cater to more users without a corresponding rise in hardware and other resource demands. Using application scalability techniques from the start lets you bypass expensive refactoring when your user base expands.

Scalable web and mobile applications also reduce the risk of downtime while streamlining maintenance — both of which bring down costs. And if you’re trying to raise funding, building scalable web and mobile applications shows investors you’re ready for growth.

  1. Improved growth/ROI potential

Scalability lets you add new features or integrations as your business evolves. This flexibility allows you to adapt to shifting market trends and customer expectations, supporting your growth.

A scalable app is also often more profitable because it’s primed for sudden transaction spikes. For example, if you’re a retailer, you can confidently offer special promotions during peak periods (like Christmas and Cyber Monday) without worrying that your app might crash.

  1. Better user feedback

Proper app scaling involves multiple quality assurance tests that let you find and fix bugs before your users do. This can help you keep bad reviews at bay.

  1. High-quality user experience

A scalable app performs smoothly at all times, supports continuous improvements, and allows personalization for a growing user base. Plus, its built-in fail-safes reduce downtime, so it’s consistently accessible. All of these improve the overall user experience. 

How to address scalability in your app

application scalability techniques

Scaling can be a resource-intensive commitment, so be sure to thoroughly assess your requirements before diving in.

Take stock of current performance barriers and predict potential issues that may come up as you grow. Ask yourself:

  • Are users frequently reporting issues (like a slow response or frequent downtime) that might suggest scalability problems?
  • What obstacles might affect your app’s operation as you add features or enter new markets?

Next, gauge your app’s current capacity. Find out:

  • How does your app perform during peak traffic periods?
  • What’s the maximum user count it can serve simultaneously without slowing down? 
  • How nimbly can your app manage varying loads?

Finally, let your growth projections guide your future planning. For example, will your current infrastructure be sufficient if you aim to double your user base in the next year? Remember to account not only for increased traffic but also for new services you plan to launch.

Challenges of building scalable apps 

Scaling an app is no piece of cake (or Cheesecake, in our case!). Before you start building your app, pay attention to these common pitfalls so you can steer clear of them:

  • Not choosing the right frameworks – Selecting a non-scalable framework can mean significant rework and inefficiencies down the line.
  • Not carrying out realistic load testing – Overlooking or downplaying the importance of load testing can cause headaches when your application goes live.
  • Not choosing the best hardware  – Non-scalable hardware lacking rapid resource provisioning can hinder scalability efforts.
  • Not optimizing your app’s design for scalability  – Without proper scalability planning, you may encounter limitations as your user base grows.
  • Not evenly distributing traffic – Imbalanced traffic distribution can cause system overloads.
  • Not spending enough time to build things right – Rushing through the development process can result in inadequate testing and hasty architecture decisions.
  • Not using experienced developers – Finding developers trained in building scalable apps can be difficult.

The good news? The right application scalability techniques can address these challenges. Let’s take a look.

Infographic: How to build scalable applications

infographic how to build scalable applications

So, how do you build scalability into a software program or app? Take note of these best practices:

  1. Use the right architecture

Your app architecture should support both vertical and horizontal scaling as user demand increases.

Monolithic vs. Microservices 

For smaller apps, a monolithic architecture might be enough. It operates like a one-man-band, with a single codebase managing all functions. But while this consolidation suits simpler apps, it becomes harder to manage as complexity grows.

On the flip side, microservices architecture resembles a team, where each service has its own codebase and performs specific tasks independently. This decentralization allows you to modify one function without disturbing the entire app, making it suitable for more advanced, ever-evolving systems.

Which one is better? Microservices win when it comes to scalability — most of the time

Unlike monolithic codebases, the microservices approach breaks things down into standalone modules which means that you can scale only parts of the application as needed. With monolithic architecture, you will need to scale the whole application


Your database is not just a place to store data. It directly affects your app’s scalability, so choose one that aligns with your growth strategy.

Relational databases like MySQL and PostgreSQL store data in structured tables, making them ideal for interrelated data. However, they struggle to scale under heavy workloads.

Meanwhile, NoSQL databases like MongoDB — which are designed for unstructured data — excel at managing large volumes. They simplify horizontal scaling due to their distributed nature.


Your choice of framework also affects your app’s scalability. Django and Node.JS are all strong contenders. Your choice should ultimately align with your overall architectural decisions.

PaaS or IaaS solutions are often ideal for many startups and SMEs. These services manage all the critical technical aspects of scaling a web application. Their Service Level Agreements also guarantee consistent uptime, enhancing reliability.

  1. Identify performance bottlenecks

Watch out for issues that can slow your app down, including:

  • Single databases – Relying on a single database can create choke points as traffic increases. Consider using a distributed database system or sharding to split data across multiple machines.
  • Incorrect data – Validate all entered data for correctness, usefulness, and security before processing. Does your app require a user to input an email address, for example? Use a simple validation tool to check if it includes an “@” symbol and a domain.
  • Caching flaws – Intelligent caching stores frequently accessed data for quick retrieval, significantly improving speed. But it’s a double-edged sword. For example, an improperly configured Varnish Cache could mishandle dynamic content (like user comments or shopping cart items.) Review your caching strategy for loopholes.
  • Not using load balancers – Load balancers allocate traffic across multiple servers so that no single server becomes overwhelmed. This supports efficient resource utilization and boosts responsiveness.
  • Bandwidth limitations – Optimize data usage to prevent hitting bandwidth limits. Consider using content delivery networks to distribute loads.
  1. Use monitoring tools

Keep an eye on vital metrics like CPU and memory usage, network throughput, and latency to spot signs of problems before they get worse.

Regular monitoring also helps you balance workloads and resources effectively. There are AWS scalability solutions (like AWS CloudWatch and AWS Auto Scaling) to simplify this task.

  1. Build in redundancies

Make sure there’s a backup for every part of your application so that if one part hits a snag, the system can keep running.

Cloud-based solutions often offer automated redundancy (including data replication and backup services) to make it easier to build resilient software and scalable applications. With redundancies in place, your app can power through sudden load surges and system issues.

  1. Use clean coding

Clean code is clear, logical, and properly documented. This is essential to scalability for several reasons:

  • Maintainability – Your application will need more updates as it grows. Clean code is easier to understand and modify, making implementing changes without disrupting existing functionality simpler. It’s also typically modular, following DRY (Don’t Repeat Yourself) and SOLID (Single responsibility, Open-closed, Liskov substitution, Interface segregation, and Dependency inversion) principles that make it easier to add new features.
  • Performance – Well-written code executes efficiently and keeps resource usage to a minimum.
  • Bug reduction – High-quality code results in fewer errors. This means less service disruption, improved user experiences, and less time spent on troubleshooting.
  • Collaboration – Efficient code is easier for other developers to understand and work with. As your team grows (or if you need to bring in outside help), they’ll be able to get up to speed more quickly.

Investing in clean coding may require more effort upfront, but it pays off by smoothing the path to scaling later on. 

  1. Don’t lose focus on security

Scaling an app involves complex architecture, codebase, and platform changes — all of which can create security weaknesses. Here are some tips for maintaining robust protection during this process:

  • Incorporate security best practices from the earliest design and development stages. Implement secure coding guidelines, strong user authentication/authorization protocols, and encryption for sensitive data.
  • Regularly use penetration testing and vulnerability scanners to detect security gaps.
  • Confirm that your app aligns with relevant compliance standards like GDPR for data protection or PCI DSS for payment security. Expect to encounter additional requirements as your app grows, especially if you’re expanding to new regions.
  • Secure your app’s environment. If you’re using cloud services, always monitor for any suspicious activities. Cloud providers often offer built-in security tools for this, but you can also use third-party security solutions for added protection.
  • Use automated security tools for continuous monitoring and routine checks. These tools can also handle patch management to automatically equip your systems with the latest security updates.
  1. Run realistic load tests 

Comprehensive load and performance tests that simulate real-world scenarios reveal how your app performs under pressure. You can adopt a behavior-driven development that aims to approach testing from a non-technical perspective.

Load tests uncover capacity gaps, while behavior-driven development gives you another perspective on testing and quality assurance and helps improve communication within the development team. These strategies help you build a high-performing and resilient app ready to grow with your business.

  1. Work with application scaling experts

Application scaling experts can assess your current architecture, identify bottlenecks, and recommend tailored solutions. They can focus your scalability efforts where improvement is needed most to maximize your ROI.

Their experience also lets them anticipate challenges and preemptively implement measures to make the transition smoother while maintaining your app’s overall stability and availability.

Cheesecake Labs has experience and expertise in building scalable applications. We’ve helped many of our clients scale their apps for growth:

  • Car subscription company FINN initially relied on outdated technologies, which were sufficient for their launch in the US (with only 10 cars) but proved inadequate for hyper-growth. We stepped in to help the company expand across 12 states and exponentially boost its US subscriber base.
  • Skyroam, a global Wi-Fi hotspot creator and service provider, sought our expertise for international expansion. We engineered a robust web server on AWS Cloud. The architecture is inherently scalable and automatically adjusts to handle peak-time traffic. Skyroam now operates in over 130 countries.
  • For Tapcart — a revolutionary SaaS platform for Shopify merchants — we built a scalable Android app architecture that aligns with the latest Google guidelines. We also established a white-label structure for rolling out custom native apps for various brands using a single codebase.
  • The influencer marketing platform Woovit has been working with our design and engineering teams for over four years. We’ve helped it scale to more than 18k streamers on board — and it’s ready for even more growth!

Ready to scale your app? Cheesecake Labs can help 

It’s clear that building scalable apps from the start is an excellent way to future-proof your business’s growth and expansion. We hope this guide will help set you up for success when building scalable apps by calling out what to look for, best practices, and pitfalls to avoid. 

But for most SMBs, having the tech talent in-house to build out a scalable app just isn’t realistic. Instead of devoting extra time, energy, and money to hiring in-house developers, partnering with outsourced developers is an excellent option. 

At Cheesecake Labs, we work on a nearshore development model and have over 10 years of experience building modern, scalable apps for businesses of all sizes.

build scalable applications

We can work with you to create stunning, effective apps that scale at a price and pace that works for your business.

Ready to get started? Let’s chat. We can’t wait to hear about your idea!

About the author.

Douglas da Silva
Douglas da Silva

Also known as Doug Gimli, I'm a developer that works with interactive solutions facing web projects, trying every day to deliver a full and great experience to users.