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The difference between IaaS, PaaS, and SaaS

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Last editedMar 20203 min read

Many businesses throughout the world are taking their business to the cloud, whether for infrastructure or application deployment. There are three key models of cloud service that businesses rely on: software-as-a-service (SaaS), platform-as-a-service (PaaS), and infrastructure-as-a-service (IaaS). But what are the differences between these service models, and which one is right for your business? Gain a little more insight into IaaS, PaaS, and SaaS with our comprehensive guide. 

Understanding SaaS, PaaS, and IaaS

So, what do IaaS, PaaS, and SaaS mean? Let’s look at these terms in a little more detail:

  • IaaS – Infrastructure-as-a-service refers to cloud-based, pay-as-you-go services such as virtualisation, storage, or networking. Examples include Amazon Web Services (AWS), Microsoft Azure, and Rackspace.

  • PaaS – Platform-as-a-service refers to software tools or hardware that are available on the internet. Examples include Google App Engine, AWS Elastic Beanstalk, and Windows Azure.

  • SaaS – Software-as-a-service refers to software that’s available via third-parties on the internet. Examples include Xero, Dropbox, and Salesforce.

Those are the basic definitions, but that doesn’t provide us with everything we need to understand the difference between IaaS, PaaS, and SaaS. We’ve put together a quick guide to IaaS, PaaS, and SaaS services, including the characteristics, advantages, and limitations of each service model.

More about SaaS

Software-as-a-service is the most commonly used cloud service option for businesses. Put simply, SaaS platforms make software that’s managed by a third-party available to users via the internet, usually for a monthly fee. Most SaaS applications run directly on your web browser, which means that there aren’t any downloads or installations required from the client.

Because SaaS is delivered via the web, there’s no need to download and install the application on every employee’s computer. Instead, all technical issues are managed by the SaaS vendor. If you’re dealing with an application that’s hosted on a remote server, available over the internet, managed from a centralised location, and takes responsibility for hardware/software updates out of the hands of users, you’re probably using a SaaS application.

So, what are the advantages and disadvantages of SaaS? Well, the major benefit of SaaS is its flexibility. It’s ready to go, it’s easy to scale, and it’s very simple to upgrade. Plus, SaaS tends to be less expensive than other cloud or on-premise options, and it can be used in a variety of business areas.

On the other hand, SaaS also leaves critical business functions in the control of a third-party, while there’s always a risk of service termination since you don’t own the software. There are also some security concerns when it comes to SaaS, as you won’t be the sole controller of your data.

More about PaaS

Platform-as-a-service provides hardware and software via the internet, offering developers a framework by which they can create customised applications. Servers, storage, and networking are managed by the third-party provider, while the developers utilizing PaaS usually manage the applications themselves.

PaaS delivery is somewhat similar to SaaS delivery, except instead of software being delivered across the internet, PaaS provides a software creation platform via the web. There are many different characteristics of PaaS, including integrated web services and databases, virtualisation technology, and a range of services to develop, test, and deploy apps.

Using PaaS offers several advantages. First off, it’s a simple, cost-effective way to develop and deploy apps, giving developers the opportunity to customise apps without needing to expend resources maintaining the software. It reduces the amount of coding and is highly scalable, while PaaS also offers easy migration to hybrid models.

However, there are operational limitations with PaaS, as the platform may limit end users’ operational capabilities. In addition, PaaS may not be an ideal solution for legacy apps and services, as they may require multiple configurations and changes to work properly.

More about IaaS

Infrastructure-as-a-service consists of scalable cloud infrastructure services offering pay-as-you-go networking, virtualisation, and storage. In essence, it’s a cloud-based alternative to on-premise infrastructure that gives businesses the opportunity to avoid investing in high-cost on-site resources.

Typically, IaaS is provided via an API or dashboard, which gives clients control over the entire infrastructure. One of the key differences between IaaS, PaaS, and SaaS is the fact that the client is responsible for managing applications, runtime, middleware, and data, although IaaS providers still manage the hard drives, networking, servers, virtualisation, and storage.

IaaS is highly flexible, and it enables clients to retain complete control. In addition, it’s easy to automate the deployment of networking, servers, storage, and processing power via IaaS. Furthermore, IaaS is highly scalable depending on the needs of your company.

But there are some limitations to be aware of. Infrastructure-as-a-service may not deliver the controls necessary to secure legacy apps, so enhancements may be necessary before you can move them to the cloud. In addition, security may be a concern as system vulnerabilities or insider threats could expose data communication between virtual machines and the host infrastructure.

Final word on IaaS, PaaS, and SaaS services

As you can see, there are many differences between IaaS, PaaS, and SaaS, particularly when it comes to how they work and what they offer to clients. As IaaS, PaaS, and SaaS are all cloud-based service models, the advantages and disadvantages of IaaS, PaaS, and SaaS are relatively similar. All suffer from potential issues with security, cost overruns, vendor lock-ins, and difficulty with customisation.

If you’re trying to decide between these service models, the choice completely depends on your business goals. For out-of-the-box software, SaaS is the best option. However, if your business is in need of a platform to build software, PaaS may be the best choice. Finally, if you need a virtual machine, IaaS is likely to be the best service for your needs.

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