How to Design a Web Application: Software Architecture 101

When to use monolithic architecture

Monolithic applications fit best for use cases where the requirements are pretty simple, the app is expected to handle a limited amount of traffic. One example of this is an internal tax calculation app of an organization or a similar open public tool.

These are the use cases where the business is certain that there won’t be an exponential growth in the user base and the traffic over time.

There are also instances where the dev teams decide to start with a monolithic architecture and later scale out to a distributed microservices architecture.

When to use microservice architecture

The microservice architecture fits best for complex use cases and for apps which expect traffic to increase exponentially in future like a fancy social network application.

A typical social networking application has various components such as messaging, real-time chat, LIVE video streaming, image uploads, Like, Share feature etc.

In this scenario, I would suggest developing each component separately keeping the Single Responsibility and the Separation of Concerns principle in mind.

Writing every feature in a single codebase would take no time in becoming a mess.

So, by now, in the context of monolithic and microservices, we have gone through three approaches:

• Picking a monolithic architecture
• Picking a microservice architecture
• Starting with a monolithic architecture and then later scale out into a microservice architecture.

Picking a monolithic or a microservice architecture largely depends on our use case.
I’ll suggest, keep things simple, have a thorough understanding of the requirements. Get the lay of the land, build something only when you need it & keep evolving the code iteratively. This is the right way to go.

When should you use NoSQL or SQL?

When to pick a SQL database?

If you are writing a stock trading, banking or a Finance-based app or you need to store a lot of relationships, for instance, when writing a social networking app like Facebook, then you should pick a relational database. Here’s why:

Transactions & Data Consistency

If you are writing software which has anything to do with money or numbers, that makes transactions, ACID, data consistency super important to you.
Relational DBs shine when it comes to transactions & data consistency. They comply with the ACID rule, have been around for ages & are battle-tested.

Storing Relationships

If your data has a lot of relationships like which friends of yours live in a particular city? Which of your friend already ate at the restaurant you plan to visit today? etc. There is nothing better than a relational database for storing this kind of data.

Relational databases are built to store relationships. They have been tried & tested & are used by big guns in the industry like Facebook as the main user-facing database.

Popular relational databases:

• MySQL
• Microsoft SQL Server
• PostgreSQL
• MariaDB

When to pick a NoSQL database

Here are a few reasons why you’d want to pick a NoSQL database:

Handling A Large Number Of Read Write Operations

Look towards NoSQL databases when you need to scale fast. For example, when there are a large number of read-write operations on your website and when dealing with a large amount of data, NoSQL databases fit best in these scenarios.

Since they have the ability to add nodes on the fly, they can handle more concurrent traffic and large amounts of data with minimal latency.

Running data analytics

NoSQL databases also fit best for data analytics use cases, where we have to deal with an influx of massive amounts of data.

Popular NoSQL databases:

• MongoDB
• Redis
• Cassandra
• HBASE

Picking the right technology for the job

Real time data interaction

If you are building an app that needs:

• To interact with the backend server in real-time, such as a messaging application, or an audio-video streaming app like Spotify, Netflix etc.
• A persistent connection between the client and server, and a non-blocking technology on the back-end.

Then some of the popular technologies which enable you to write these apps are NodeJS, and the popular Python framework known as Tornado. If you are working in the Java Ecosystem you can look into Spring Reactor, Play, and Akka.

Peer-to-peer web application

If you intend to build a peer to peer web app, for instance, a P2P distributed search engine or a P2P Live TV radio service, something similar to LiveStation by Microsoft, then you’ll want to look into JavaScript, protocols like DAT, IPFS. Checkout FreedomJS, it’s a framework for building P2P web apps that work in modern web browsers.

CRUD-based Regular Application

If you have simple use cases such as a regular CRUD-based app, then some of the technologies which you can use are: Spring MVC, Python Django, Ruby on Rails, PHP Laravel, ASP .NET MVC.

Simple, small scale applications

If you intend to write an app which doesn’t involve much complexity like a blog, a simple online form, simple apps which integrate with social media that run within the IFrame of the portal, then you can pick PHP.

You can also consider other web frameworks like Spring boot, Ruby on Rails, which cut down the verbosity, configuration, development time by notches & facilitate rapid development. But PHP hosting will cost much less in comparison to hosting other technologies. It is ideal for very simple use cases.

CPU and memory intensive applications

Do you need to run CPU Intensive, Memory Intensive, heavy computational tasks on the backend such as Big Data Processing, Parallel Processing, Running Monitoring & Analytics on quite a large amount of data?

Regular web frameworks & scripting languages are not meant for number crunching.
Tech commonly used in the industry to write performant, scalable, distributed systems is
C++.

It has features that facilitate low-level memory manipulation, providing more control over memory to the developers when writing distributed systems. Majority of the cryptocurrencies are written using this language. Here’s a great course to Learn C++ for free.

Rust is a programming language similar to C++. It is built for high performance and safe concurrency. It’s gaining a lot of popularity lately amongst the developer circles.
Java, Scala & Erlang are also a good pick. Most of the large scale enterprise systems are written in Java.

Go is a programming language by Google to write apps for multi-core machines & handling a large amount of data.

Julia is a dynamically programmed language built for high performance & running computations & numerical analytics.

How to become a software architect?

If this all sounds interesting, then you may aspire to be a software architect. But where do you start? Well, it’s extremely uncommon for someone to start out as a software architect, so most software engineers work for a few years before they take on designing architecture.

One of the best ways to become familiar with software architecture is by designing your own web applications. This will force you to think through all the different aspects of your application, from load balancing, message queueing, stream processing, caching and more.

Once you start to understand how these concepts fit into your app, you’ll be well on your way to becoming a software architect.

As an aspiring software architect, you need to constantly expand your knowledge and stay on top of the latest industry trends. You may start by learning one or more programming languages, work as a software developer, and gradually make your way.

Where to go from here?

While there was a lot covered in this post, we’ve merely touched the surface on this topic. We still have yet to explore REST APIs, high availability, and CAP theorem.

If you’d like a deep dive into software architecture, I highly recommend Web Application and Software Architecture 101. It walks you step by step through different components & concepts involved when designing the architecture of a web application.

You’ll learn about various architectural styles such as the client-server, peer to peer decentralized architecture, microservices, the fundamentals of data flow in a web application, different layers involved, concepts like scalability, high availability and much more.

It will also help you with the software engineering interviews, especially for the full stack developer positions.

Happy learning!

Keep reading about software architecture