SaaS, PaaS, and IaaS: what's the difference?

It’s hard to imagine a world without Google Apps, Dropbox, Slack, Netflix and Spotify. As consumers, our habits have been changed by cloud computing in a relatively short time span.

Yet, it’s not that long ago that businesses were debating whether to transition into the cloud at all. The internet was abuzz with debate around security, and companies were worried about missing out on potential revenue and opportunities if they waited until cloud services matured. Now, these once novel services are ubiquitous: everyone from SMEs to enterprises has embraced life in the cloud.

So, what does this mean for those who need to make business decisions about cloud services and infrastructure? Well, given this ubiquity, chances are it’s not only experts like cloud architects or cloud engineers who need to understand what’s on offer.

Everyone from newbie programmers to start-up founders and finance directors need to get to grips with the features and relative benefits of cloud computing – using a network of servers to host, store, manage, and process data online.

You’re likely to come across three main ways businesses are making use of cloud computing. In increasing order of complexity, hands-on management time and customisation options, these are: SaaS – Software as a Service; PaaS – Platform as a Service; and IaaS – Infrastructure as a Service.

Let’s look at each of these in more detail to discover the differences between them, and when you might want to use each one.

SaaS – Software as a Service

Also known as cloud application services, SaaS is the most commonly used and most straightforward cloud option for businesses. Simply put, it uses the internet to deliver applications that are managed by a third-party vendor. Well-known examples include Salesforce, Cisco WebEx, Concur and GoToMeeting, as well as the applications we mentioned earlier (Google Apps, Dropbox, Slack, Netflix and Spotify).

Most SaaS applications run directly through a web browser, which means businesses don’t need to worry about managing or maintaining downloads or software installations. They can release software updates automatically, and customer support is made simple since everyone is using the same, up-to-date version. Customers are, in effect, renting the software.

SaaS offers plenty of advantages to companies by cutting the time and money spent on routine tasks, especially installing, managing and upgrading software.

Is SaaS right for you (or your business)?

If you fall into one of these categories then SaaS is worth considering:

• You’re offering an application that is used infrequently, such as tax software
• Running a start-up or small company
• Launching all your support and ecommerce systems quickly is vital for cash flow and you don’t have the time or perhaps the know-how to deal with server or software issues
• Running a short-term project that only has time and budget for a quick, easy, and affordable solution
• Running applications that need both web and mobile access.

But with flexibility, there are also some trade-offs. So, what are the limitations and drawbacks of SaaS?

• Loss of control: When you use a hosted solution you give control to a third-party provider.
• Limited applications: SaaS is gaining in popularity. However, there are still many software applications that don't offer a hosted platform.
• Connectivity requirements: You can't use these applications without an Internet connection so if yours goes down, everything stops.
• Variable functions & features: Hosted applications can be limited in function so you’ll need to evaluate each application on a case-by-case basis to make sure you have all the features you need.
• Slower speeds: SaaS applications generally run at slightly slower speeds than client/server applications.

PaaS – Platform as a Service

As cloud platform services, PaaS provide cloud components to software and are mainly used for applications. PaaS offers a framework for developers to build upon and create customised applications. Well-known examples include AWS Elastic Beanstalk, Windows Azure, Heroku, Force.com, Google App Engine and OpenShift.

PaaS differs from SaaS in that IT administrators can have control over their data and applications, while all the servers, storage, and networking are managed by the enterprise or a third-party provider (the same way as SaaS).

This control is the biggest advantage of the PaaS model. However, it comes with the drawback that developers can only control what’s built on the platform. If an issue develops with the hardware or operating system, or there’s a power outage, the whole system goes down and there’s nothing that can be done to restore the software – you have to wait for the provider to fix it.

Is PaaS right for you?

You may need to use PaaS:

• For streamlining workflows if you have multiple developers working on the same project
• When working with multiple vendors, to create a speedy and flexible process
• For creating customised applications
• If cost is an issue, you can drastically reduce this by using PaaSto solve many of the challenges that come with developing and deploying an app at speed.

PaaS clearly offers a good balance between control, flexibility and managed services. So, what are some of its limitations and drawbacks?

• Data security: Security options may be limited as customers may not be able to deploy services with specific hosting policies.
• Integrations: Connecting the data stored within an onsite data centre or off-premise cloud is highly complex. This may affect which apps and services can be adopted.
• Vendor lock-in: Requirements that drive decisions for a specific PaaS solution may change over time.
• Customisation of legacy systems: Several customisations and configuration changes may be needed for legacy systems to work.

IaaS – Infrastructure as a Service.

Finally, we come to IaaS – cloud-based infrastructure resources delivered to organisations, using virtualisation technology to help them build and manage their servers, network, operating systems, and data storage. This option offers the most customisation and control for IT managers. Examples include the two most popular cloud platforms: Amazon Web Services (AWS) and Microsoft Azure, as well as DigitalOcean, Linode, Rackspace, Cisco Metacloud, and Google Compute Engine (GCE).

IaaS customers control their own data infrastructure without having to physically manage it on-site. They access and store data on servers through a dashboard or API (application programming interface). IaaS is a flexible solution for companies looking to scale and grow as they can pay for the amount of storage and server space they need to build their hardware or software, and add to it as they need more. They don’t need to host and manage servers themselves on-site. IaaS is for companies who are building their own cloud-delivered technologies.

Is IaaS right for you?

Some examples of where IaaS is useful include

• Running an application or website
• Analysing large amounts of data or carrying out data mining which requires incredible amounts of computing power. This is the most cost-effective way to harness it
• Building virtual data centres for large companies that need a highly scalable, effective and secure environment.

So, what are some of the limitations and drawbacks of IaaS?

• Dependency on the provider: Their responsibility is to make sure the service is available and secure.
• Internet access is essential
• Vendor tie-in: It’s very complicated to change providers.
• Possible privacy issues: Especially dependent on the provider’s server locations.

Making the decision between SaaS, PaaS and IaaS is a complex process. Hopefully we’ve given you a good introduction today.

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