Business growth is complicated by many factors, from the size of the company’s staff to the app’s usage capacity. In the digital-first market, the latter becomes especially important. It is not uncommon to see companies trying to address the issue by throwing more hardware at the task – often to no effect. In reality, making an app scalable takes both strategic vision and the right tools.
Simply put, scalability is the app’s ability to grow in scope. Depending on the app's type, it may involve the ability to remain responsive, handle uneven loads, or store large volumes of data. In the end, it can be boiled down to the balance between performance and resource availability. As long as adding new resources provides enough of an increase in performance, the app can be considered scalable. The problem is, the rate of demand often outpaces the benefits of resource addition.
Scalability is particularly important for digital businesses like m-commerce startups that are expected to grow in popularity at an increasing rate. Suppose you are a new Amazon, processing a modest $7 billion worth of transactions annually. Every three years, you need to double your app’s throughput, which, in the best-case scenario, involves buying more and more servers, building new infrastructure, and pouring money into custom mobile application development.
Let’s say you’re okay with constantly mounting expenses and write it into your business plan. Now imagine something happens that brings in an influx of customers. Not only will it stretch the budget thin, but it will also probably deal a blow to performance. Research shows that modern customers are not the most patient kind and will happily bounce off even at the slightest slowdown. So, scalability is essential for any kind of strategic perspective in the digital-first economy.
Making an app scalable involves a whole host of factors. For a simple application, it may be achieved by adding new hardware to increase throughput. More complex products like enterprise solutions would require a systemic approach integrated with the app’s strategy to address all possible problems, including:
- Low computing power: The app is taking too long to perform the operation due to insufficient resources
- Lack of integration: Different components of the app are having trouble communicating with each other
- Inefficient code: The codebase is poorly organized and difficult to work with
- Inefficient database handling: The app overloads the database with queries
- Poor server configuration: The servers cannot put all requests through
- Poorly organized testing process: The issues are difficult to spot and trace
As you can see, some of the problems can be solved by application developers simply by following the best practices in the field, while others require estimating the rate of growth and adding the scalability considerations to the deployment strategy as early as possible.
A successful commercial app is expected to tick these four boxes in order to be scalable:
- Performance: Running smoothly no matter the load
- Availability: Working at all times
- Data integrity: Nothing is lost due to malfunction
- Monitoring: Issues are identified and addressed
While there is no single way to meet all these requirements in every case, several recommendations can make the task easier.
As the industry of app development is catching up with the demand, more and more tools acquire the features that can alleviate the problem. Some programming languages are built with scalability in mind – Elixir, for instance, boasts its process organization that is scalable both vertically and horizontally. Other languages introduce elements that enable scalability, like Python’s Flask framework. The same can be said about databases – the development of NoSQL, for example, was partially driven by the need to circumvent the limitations of scale in relational databases.
There is probably at least one element in any app’s architecture that, once removed, will render the entire service unusable. In technical terms, this is known as SPOF (single point of failure), and, in the case of the digital-first market, it can easily become a decisive blow to the business. The audience of digital products is extremely sensitive to subpar experience, so be sure to have a backup of everything through replication.
Once your app becomes popular, you’ll have to deal with uneven loads that can easily overwhelm your database with queries. One way to reduce the load is by caching the data. Of course, caching means additional expenses on memory, so the trick here is to cache only what is most often requested. Another trade-off is in that cached data is not recalculated each time, so apply it only where data freshness is not critical.
It is tempting to think that an app can be made scalable simply by throwing more computing power in the firebox to keep it running. In reality, this is like trying to cure obesity by loosening the belt. To truly address the issue, the principles of scalability have to be taken into account as early as possible and integrated with other aspects of app development.
Originally published at DZone