Cloud Computing – What is Function-as-a-Service (FaaS)?

Cutting-edge technologies like artificial intelligence, machine learning, and cloud computing are shaping our everyday lives. From going shopping (online & offline) to setting up appointments with a doctor, technology is governing much of what we do today. Managed Cloud Services are becoming a trendy way for companies worldwide to run their businesses. And Function-as-a-Service, also known as FaaS, is today’s fastest-growing cloud computing model.  

But what is FaaS? How is it linked to serverless and microservices architectures? And why is it growing so rapidly?  

Let’s dig deep to uncover the answers to these questions.  

Function-as-a-Service (FaaS)

If you want to host an application on the Internet, you must provide a physical or virtual server. You also have to manage an operating system and manage web server hosting procedures.  

The Function-as-a-Service cloud computing model removes all these requirements. Your cloud service provider handles all this – physical hardware/infrastructure, virtual machine OS, web server management, etc. – to enable your developers to focus on the core product instead.  

Here’s what it is.  

Function-as-a-Service (FaaS) is a type of cloud computing model that enables software developers (cloud customers) to build, deploy, run, and manage applications as functions without worrying about the infrastructure. Such infrastructure is usually a vital part of developing and launching applications.  

In other words, companies employing the FaaS model run their applications directly from the cloud instead of hosting them on a server. It is time-consuming to run, manage, and maintain servers. Hence, a serverless model like FaaS is quickly gaining traction among businesses.  

The best part about FaaS is its event-driven nature, which means that the code executes as a result of some event that triggers its execution. These events include API requests, scheduled events, events in the database, etc. And you pay for it only when the functionality is executed. These unique features of the Function-as-a-Service model are the reason behind its rise in popularity and use.  

In the traditional cloud computing model, the code runs on the server continuously, and you are charged for it. Under the conventional model, one also has to provision infrastructure, while FaaS removes the need for it. Therefore, all the other types of cloud computing models must operate on a server at any given time. But with FaaS, the model runs only when a function is executed; it stops after the code is executed.  

Examples of FaaS include the following:  

  • AWS Lambda  
  • Microsoft Azure Functions  
  • Google’s Cloud Functions  
  • OpenFaaS  
  • IBM Cloud Functions  

FaaS and Serverless Architecture – Are They the Same Thing?

Many people use the terms FaaS and serverless interchangeably, but that is a mistake. While there are similarities between the two, there are apparent differences as well.   

Let’s see what these similarities and differences are.  

In the beginning, both terms used to mean the same thing, more or less. However, with time serverless architecture’s scope expanded to include a set of practices and architectural models that employ the in-depth use of common services, including the custom business logic present in FaaS.  

Traditional applications and microservices can both use serverless architecture insofar as they abide by state management and scaling requirements while being containerized.  

The major similarity between the FaaS and serverless architecture is that both emphasize removing the need for users to manage and configure infrastructure. For example, storage service offered by a cloud service provider means that all the underlying infrastructure is handled by the service provider, thus removing the need for the users to manage it themselves.  

FaaS is an extension and a subcategory of serverless architecture. The latter focuses on any service category, such as database, storage, compute, API gateways, etc. FaaS, as opposed to serverless, is governed by an event-driven cloud migration strategy where containers or the application code run only in response to some requests (e.g., API requests) or events (e.g., scheduled events).  

Hence, the primary difference between the two is that while both eliminate the need for users to configure and manage the underlying infrastructure, serverless runs continuously and FaaS does not. Function-as-a-Service (FaaS) only runs for a short duration, executes the function, and then shuts down, thus saving you incremental business costs.  

This makes Function-as-a-Service one type of serverless architecture, yet the difference between the two remains. It helps to think of serverless architecture as an umbrella term under which FaaS features.  

Function-as-a-Service (FaaS) and Microservices

Microservices is an architectural approach employed in software development. It builds software applications as a set of loosely coupled services that communicate through lightweight protocols or APIs. Moreover, microservices architecture helps you develop complex applications using the serverless architectural approach.  

You can deploy these loosely coupled services independently. They are testable, highly maintainable, and owned by small, self-contained teams. As an architectural approach, microservices enable your software developers to rapidly develop and scale your applications. It also reduces the time to market, releases new features, and fixes bugs.  

Microservices applications are the opposite of yesteryear’s monolithic, tightly coupled applications where all the processes are run as a single service. Here, if you want to meet the surge in demand for one of your app’s processes, you will have to scale the entire application. Thus, experimentation with new ideas or adding new features to a monolithic application becomes a very tedious and challenging task.  

So, how are FaaS and microservices related?  

The principle behind the two is the same. In microservices, each service is supposed to do just one thing. It’s the same for FaaS, where each function is supposed to carry out a single operation. Moreover, both FaaS and microservices use virtual containers. FaaS functions are executed in containers, and microservices applications are also usually deployed in containers.  

Advantages of Function-as-a-Service (FaaS)

  • Increased Development Speed – The most significant benefit of Function-as-a-Service is that it enables your developers to focus on the application code itself instead of worrying about managing and configuring the underlying infrastructure. Thus, FaaS expedites your application development process.  
  • Scalability – Your developers do not need to concern themselves with creating contingencies in case your application process experiences a spike in demand. That is because FaaS is, by its very nature, scalable. Your cloud service provider looks after all your scalability requirements.  
  • Cost efficiency – Another critical advantage of the FaaS cloud computing solutions for business is that your service provider does not charge you for idle computing time. Instead, you are only charged based on the number of functionality executed. Moreover, it also saves you a lot of money since you don’t have to manage and configure the underlying infrastructure.  
  • Efficiency – The FaaS model significantly reduces the application development and deployment periods since costs are less and you can run more workloads.  


While FaaS has a few drawbacks, its benefits far outweigh its disadvantages. These drawbacks include increased testing complexity, less system control, and CI/CD pipeline integration issues.  

Such issues can be attributed to the fact that Function-as-a-Service (FaaS) as a cloud computing model emerged only recently. With time, intelligent developers and innovative tech companies will indeed overcome these issues.  

If you need assistance with cloud computing models, Azure DevOps automated deployment, or services, contact us at [email protected]. 

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