When you describe a perfect app, scalability is a feature that is going to be mentioned in ten out of ten cases. A high-performance app has to be scalable, period. But what is scalability and why is it so important?

In simple words, scalability is an app’s ability to grow together with the demand. A scalable app can accommodate the growth of user request volumes, both gradual and sharp, without losing performance or availability.

Why should we care about scalability? Well, any business is supposed to grow in terms of getting more customers that, in turn, create higher loads on the app. Besides, there are always those peak loads, both sudden and predicted, that will put the app’s performance to the test.

The Covid-19 pandemic, for example, caused many customer-facing apps to endure much higher loads that they did not expect. A city shuts down public transportation due to quarantine – a demand for taxi services increases. Shops get closed – delivery apps see a surge in customer requests. Schools and colleges switch to online education – communication and eLearning platforms experience peak loads.

Even without such dramatic circumstances, peak loads happen. If your marketing team plans a Christmas special, you can surely expect a peak in the second half of December. When the deadline for tax return filing approaches, the online platforms where taxpayers can submit their forms get overloaded. These are examples of planned or expected, loads to which app developers should be prepared, too.

What are the characteristics of a scalable app?

Scalability per se is just an abstract concept that can, however, translate into some very real benefits. A scalable app is an app that:

• Can perform under high loads without losing availability;
• Continues to load content with the usual speed regardless of the number of requests;
• Allows smooth updates;
• Is easy to expand by adding new features.

Obviously, scalability plays a key role in winning customers’ loyalty and retention. Pages that take forever to load and resources that throw errors when they are needed surely make users want to look for alternatives. Hence, scalability.

How to build a scalable app?

The most important thing here is that scalability should be planned for from the very beginning. If you have a working app that turns out to be poorly scalable, you can hardly fix it by adding more servers. It does not always work that way, you need to build scalability in the very architecture of your app.

Below are several tips that can help you plan a truly scalable app.

Implement scalability at the design level

Plan for scalability every step of the way. Think how you prefer to scale – horizontally or vertically. The difference is that you achieve horizontal scalability by adding more servers and vertical – by upgrading the existing ones. There are pros and cons for both approaches but the common opinion is that while horizontal scaling is more costly, it is easier to implement.

Consider using cloud storage and servers. Clouds provide almost effectively unlimited storage space that can be obtained quickly and at a reasonable cost. Moreover, you can increase your cloud resources for the period when you expect high loads and then reduce them again.

Choose the tools and frameworks that will ensure proper scalability and performance as well as load balancing software to distribute the load between servers. If you are using third-party software, make sure you choose those capable of guaranteeing high scalability to avoid bottlenecks.

Choose scalable hardware

If you opt for hardware servers rather than cloud resources, make sure you will be able to scale your system either horizontally or vertically. Verify that you can upgrade your CPUs and install additional RAM if needed.

Alternatively, if you are planning to scale horizontally, make sure that you can integrate additional servers smoothly.

Use cache

Caches store data that may be reused in the future. Caches improve the loading speed by supplying the required data rather than downloading it once again.

During peak loads, caches can improve app performance and create better user experiences.

Schedule regular monitoring and maintenance

Maintenance is important not only for app scalability but for any aspect of its operation. With regular maintenance, you can make sure that all app components work and communicate as designed, that you are using the most current software versions, that any third-party updates have been implemented.

To perform regular maintenance, you need to implement continuous monitoring of the key components of your app to be alerted in the event of any failures or service deterioration.

Do load testing

During load testing, you simulate a situation when multiple users access your service simultaneously. Such tests help to verify that your app, indeed, is ready for both sudden and planned peak loads and will continue providing the service with no failure or degradation.

Load testing gives you a number of valuable insights:

• Whether your infrastructure is suitable for your type of app;
• Whether your app can withstand high loads;
• Whether your app can recover from a failure resulting from overloading;
• What is the maximum number of users your app can serve at a time.

Load testing can help you plan upgrades and capacity extensions that can accommodate peak loads.

Build a scalable application with QuickBlox

How can QuickBlox help you in building a truly scalable app? Messaging and chatting applications can be susceptible to overloading, and if you want to be prepared for any peak loads, consider including QuickBlox in your infrastructure.

With QuickBlox, you will quickly create your own secure real-time messaging app with infrastructure built with scalability in mind. The QuickBlox APIs and SDKs allow setting up feature-rich communication apps for any number of users. Using the instant messaging API developed by QuickBlox, you can integrate a chatting or calling feature into your app to enable real-time communication for your users.

Contact us to learn more about how to create a fully functional communication app including real-time chat, file upload, voice, and video calling. If you need a reliable, high-performance communication app that grows together with your business, QuickBlox can do it for you.