Serverless architecture
Serverless architecture has become a real buzzword in the tech world, promising scalability, cost savings, and simplified infrastructure management. But does it really deliver on those promises? In this article, we explore what serverless architecture is exactly, why it is so popular, which use cases it is ideal for, and in which situations it is not the best choice. We also take a closer look at Function as a Service (FaaS) and discuss whether serverless solutions can also be replicated on-premises.
What is serverless architecture?
Serverless architecture is a cloud computing model in which the cloud provider dynamically manages the allocation of machine resources such as CPU, RAM, and disk space. Unlike traditional server setups—where you are responsible for managing the server infrastructure yourself—serverless allows you to focus primarily on developing your applications. The deployment of your microservices or code is fully automated. This way of working and deploying also fits in perfectly with an event-driven architecture, where code is executed in response to events. Cloud providers offer specific (serverless) services for this purpose. For example, Amazon Web Services offers services such as and Simple Notification Service, while Google Cloud Platform offers solutions such as Eventarc and Pub/Sub.
With the many services and tools offered by cloud providers, it is possible to build a complete product without ever having to manage a server yourself. In short, serverless means that you can deploy applications without worrying about server management. The name is somewhat misleading: servers are still there, but you no longer have to manage them yourself.
Why is it hyped?
Serverless architecture has received a lot of attention for several reasons. Let's take a look at some of the most important ones.
Scalability
Serverless automatically scales your application based on the load. Whether you are dealing with a sudden spike in traffic or a quiet period, serverless ensures that your application adapts to this. However, it is important to keep in mind that there are limits to how far certain services can scale in order to ensure stability. That is why it remains essential to monitor your architecture closely.
Cost-effective
You only pay for what you actually use. There is no need to reserve and pay for server capacity that is idle most of the time. This fits in well with the scalability of serverless, especially when the load is unpredictable or sometimes almost zero. You don't waste resources on a safety margin. At the same time, serverless is not the most cost-effective option in all scenarios, so a thorough cost analysis remains important.
Less maintenance
It's true that server management and certain infrastructure-related tasks are largely eliminated. But don't fire your engineers just yet: even a serverless architecture needs to be managed, it's just that the type of work changes. You still need monitoring to ensure stability and identify bottlenecks or problems. The focus shifts from traditional metrics and OS upgrades to things like execution times, errors, cold starts, and possibly throttle limits. In addition, correctly configuring components such as your API gateway, CDN, and cloud functions remains important. Perhaps most important of all is managing roles and permissions for all the different components within your serverless architecture.
Does serverless deserve the hype? And how can it be cheaper?
The hype surrounding serverless is largely justified, especially when you consider the advantages in specific scenarios. At the same time, it is important to carefully evaluate whether serverless is right for your situation. Below you can see how and when serverless can be more cost-effective.
Highly variable and unpredictable load
For applications with highly fluctuating traffic, such as event ticketing or alerting systems, serverless offers immediate scalability. Resources are adjusted in real time, keeping your application responsive and available without having to over-provision your infrastructure.
Event-driven architecture
Serverless is ideally suited for event-driven applications, where functions are triggered by specific events, such as data uploads, user interactions, or system notifications. For example, AWS Lambda can automatically execute a function when a file is uploaded to Amazon S3. This makes serverless ideal for real-time data processing and asynchronous workloads.
Low-load applications
When an application requires few resources, serverless is an excellent choice. Consider, for example, tasks that run for a few minutes once a day, such as collecting, consolidating, and exporting daily cloud costs.
Another good example is a static website for an event. Amazon S3 can host the website, and Amazon CloudFront ensures fast response times worldwide and manages SSL certificates. In one customer implementation, the cost of running the website was approximately 60 cents per month: about 50 cents for DNS and the hosted zone, and the remaining 10 cents for storage in S3 and traffic via CloudFront.
In short: serverless deserves the hype, especially in scenarios with unpredictable loads, event-driven architectures, and applications with low resource requirements. Outside of these situations, however, a different architecture may be better and cheaper—as always, it depends.
When you should not use serverless
Despite its advantages, serverless is not a silver bullet for every scenario. Knowing when not to use something is perhaps even more valuable than knowing when to use it. Below are a number of situations in which serverless may not be the best choice.
High throughput and low latency requirements
Cold starts, resource limits, and the fact that serverless services depend on external components to deliver their functionality can affect latency and throughput. When low latency and high throughput are absolute requirements, serverless is probably not the right solution.
An online multiplayer gaming platform is a good example here: these types of applications do not typically benefit from a serverless architecture. Support systems—such as an email or notification service—can, on the other hand, be ideally suited for serverless.
Long-running processes
Serverless functions usually have a maximum execution time (for example, 15 minutes with AWS Lambda). Applications with long-running processes therefore encounter limitations.
There are serverless platforms such as AWS Batch where this time limit is less of an issue. But at that point, it may be more efficient to use a server that you start when needed and stop again when finished. Again, it all depends on the specific use case.
Complex deployment dependencies
Applications with complex deployment requirements or extensive local development environments may find serverless limiting. Serverless platforms do not always support all necessary dependencies or configurations.
In such cases, you often have to integrate multiple third-party services to compensate for missing functionality, or rearchitect parts of your application to fit within the serverless paradigm. This can lead to additional operational complexity, technical debt, and greater dependence on external suppliers for critical components. This, in turn, has an impact on scalability, performance, and troubleshooting.
For highly customized or complex deployments, a more traditional infrastructure is therefore often more suitable than serverless—unless the platform develops further and starts to support these needs natively.
Some points to consider
There are also other considerations that may prevent organizations from switching to a serverless architecture:
Vendor lock-in
Because serverless solutions are closely tailored to a specific cloud provider, it can be difficult to migrate to another provider later on. Cloud providers often offer similar services, but these are rarely interchangeable on a one-to-one basis. The more vendor-specific services you use, the greater the risk of lock-in.
complexity
Serverless solutions often appear simpler from a distance, but in practice, troubleshooting and debugging can be complex. Due to the distributed nature of serverless architectures—where multiple services and platforms work together—it can be difficult to trace problems that span multiple components. Implementing good monitoring and logging strategies is therefore essential.
Stateless character
Many serverless services are stateless. This can introduce additional complexity when an application needs context or memory from previous invocations. In such cases, state must be stored externally, which can complicate the architecture.
Security
The underlying infrastructure is beyond your direct control. When working with sensitive data, this can be a dealbreaker, as you are dependent on the security measures and compliance of the cloud provider. In some sectors or use cases, this is simply not acceptable.
In summary
Serverless architecture offers clear advantages, especially in scenarios where scalability, cost efficiency, and reduced maintenance are key considerations. The ability to support event-driven applications and automatically handle variable loads makes serverless an attractive choice for many modern organizations.
But as with any technology, serverless is not a one-size-fits-all solution. Potential drawbacks, such as latency issues, execution limits, and vendor lock-in, must be carefully weighed against the benefits. As with any architectural choice, it is crucial to thoroughly understand the specific needs and limitations of your application. Only then can you determine whether serverless architecture truly aligns with your goals, or whether a more traditional approach is better suited to your situation.
Are you curious to find out whether your organization could benefit from a serverless approach? Feel free to contact us—our engineers will be happy to brainstorm with you and help you find a suitable solution!
