The Ultimate Guide to Building Scalable Web apps: Part 1

Why should you invest in building large-scale web apps?

Performance is the magic word, when it comes to scalable web apps. Large scale web applications can effectively achieve high performance irrespective of the number of people using it any given moment in time. It can effortlessly handle large volumes of data, and adapt to voluminous load changes without impacting the quality of operations.

That being said, let us explore some of the characteristic features of scalable web apps:

• Performance: Whether it is hundreds, thousands, or millions of users transactions per second, large-scale applications can handle voluminous user requests on applications easily.
• Distributed: Large-scale applications are distributed with servers that are geographically closer to users, leveraging CDNs. In absence of data centers, you can run in the cloud.
• Data: Deal with a large volume of data and with lots of data types such as customer behavior tracking, page views, logs, products, orders, and more. It can handle different data types.
• Availability: It can be accessed at any time of the day or week.

That being said, let’s dive in and explore the important aspects that you have to consider before scaling your web applications!

5 things to consider while building large scale web apps

1. The need for scaling

Scaling is an arduous and expensive exercise. If you intend to add new features to your system, or make the existing ones more sophisticated, you need to make sure that the current functionality can handle the changes.

Ensure that your expectations of scaling justify the expenses. How do you find out whether a large scale web application is necessary for your business? Here are a few questions to help you decide:

• Do you expect an increase in the number of users? If yes, what percentages are you looking at, and what is the timeframe?
• How long can you current customer/user base fit the server you currently use?
• What storage plan do you use? Is it flexible enough to accommodate size changes?

2. Metrics to define scalability challenges

Once you’re clear that your application needs to be scaled, the next step is to decide what scalability issues you need to focus on. Track the following metrics to get a complete picture:

• 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  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. App monitoring tools

 The first aspect of building scalable web apps, is to choose the right app-monitoring tools. These tools can identify problems/bottlenecks which hinder your ability to scale, and enable you to resolve them on time.

Some examples include 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.

4. Infrastructure

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.

If you don’t yet use a PaaS, consider the following options:

• Amazon Web Services Elastic Beanstalk: It automatically handles deployment details including capacity provisioning, load balancing, auto-scaling, and application health monitoring.
• Heroku: It always knows what’s going on with your applications owing to built in monitoring of throughput, response times, memory, CPU load, and errors.
• IBM Cloud PaaS: It helps you modernize existing applications, embed additional security, and develop new apps for digital initiatives.
• Microsoft Azure PaaS: It is a complete development and deployment environment in the cloud, with resources that enable you to deliver everything from simple cloud-based apps to sophisticated, cloud-enabled enterprise applications.

SEE ALSO: Choosing the Right Technology Stack for Web application development 

5. Architecture

The choice of an architecture pattern depends on your app’s unique requirements. The most commonly used architectures are listed below:

1. Layered architecture

This architecture consists of multiple layers, and a database at the foundation, as the name suggests. Each layer has a specific task, and data usually travels from top to bottom.

Pick this architecture if you need to develop:

• new apps within a limited time frame
• apps that require strict standards in maintenance and testing

If your business leverages traditional IT processes or have developer teams that lack a strong understanding of different architectures, layered architecture is the ideal choice. 

2. Event driven architecture

This architecture consists of a central unit along with modules that interact with data, which is specific to them. When an event triggers the central unit, it delegates the data to the dedicated module.

Event-driven architecture is most suitable for:

• Developing asynchronous systems
• 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.

Microkernel architecture is most suitable for:

• apps that have a wide target audience
• instances where you can clearly distinguish between basic and higher needs

4. Micorservices architecture:

Microservices is an architectural style that structures an application as a collection of services that are

• Highly maintainable and testable
• Loosely coupled
• Independently deployable
• Organized around business capabilities
• Owned by a small team

The microservice architecture enables rapid, frequent and reliable delivery of large, complex applications. It also enables you to 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

This blog is the first of a two-part series on building scalable web apps. In the subsequent blogs, we’ll explore other considerations that you have to take into account while developing scalable web apps. We’ll also look at the benefits, and challenges associated with scalable web apps, and the strategies to overcome challenges.