When to use SaaS, PaaS, and IaaS

What’s The Difference Between SaaS, PaaS, IaaS?

When your business has made the decision to consider cloud services for your application or infrastructure deployment, it’s important that you grasp the fundamental differences between the core categories of cloud services available.

The cloud is a very broad concept, and it covers just about every possible sort of online service, but when businesses refer to cloud procurement, there are usually three models of cloud service under consideration, Software as a Service (SaaS), Platform as a Service (PaaS), and Infrastructure as a Service (IaaS). Each has its own intricacies and hybrid cloud models, but today we’re going to help you develop an understanding of the high-level differences between SaaS, PaaS, and IaaS.


Software as a Service

In some ways, SaaS is very similar to the old thin-client model of software provision, where clients, in this case usually web browsers, provide the point of access to software running on servers. SaaS is the most familiar form of cloud service for consumers. SaaS moves the task of managing software and its deployment to third-party services. Among the most familiar SaaS applications for business are customer relationship management applications like Salesforce, productivity software suites like Google Apps, and storage solutions brothers like Box and Dropbox.

Use of SaaS applications tends to reduce the cost of software ownership by removing the need for technical staff to manage install, manage, and upgrade software, as well as reduce the cost of licensing software. SaaS applications are usually provided on a subscription model.

Platform as a Service

PaaS functions at a lower level than SaaS, typically providing a platform on which software can be developed and deployed. PaaS providers abstract much of the work of dealing with servers and give clients an environment in which the operating system and server software, as well as the underlying server hardware and network infrastructure are taken care of, leaving users free to focus on the business side of scalability, and the application development of their product or service.

As with most cloud services, PaaS is built on top of virtualization technology. Businesses can requisition resources as they need them, scaling as demand grows, rather than investing in hardware with redundant resources.

Examples of PaaS providers include Heroku, Google App Engine, and Red Hat’s OpenShift.

Infrastructure as a Service

Moving down the stack, we get to the fundamental building blocks for cloud services. IaaS is comprised of highly automated and scalable compute resources, complemented by cloud storage and network capability which can be self-provisioned, metered, and available on-demand.

IaaS providers offer these cloud servers and their associated resources via dashboard and/or API. IaaS clients have direct access to their servers and storage, just as they would with traditional servers but gain access to a much higher order of scalability. Users of IaaS can outsource and build a “virtual data center” in the cloud and have access to many of the same technologies and resource capabilities of a traditional data center without having to invest in capacity planning or the physical maintenance and management of it.

IaaS is the most flexible cloud computing model and allows for automated deployment of servers, processing power, storage, and networking. IaaS clients have true control over their infrastructure than users of PaaS or SaaS services. The main uses of IaaS include the actual development and deployment of PaaS, SaaS, and web-scale applications.

There are a lot of providers offering Infrastructure as a Service such as Navisite, exoscale, and Softlayer reach with their own unique value proposition and service portfolio to choose from.

ComputeNext provides a brokerage service for IaaS, so that you can be sure you’re choosing the right IaaS provider for your application needs. With normalized access to over 20 cloud providers from a single API you can compare price and performance across providers to find the best fit – and then build and deploy without getting locked in to just one platform.

Hopefully you now have a good grasp of the differences between SaaS, PaaS, and IaaS.

If you have any questions, feel free to ask in the comments.

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  • Smsoma

    I want one example explain 3 iaas paas saas

    • Ashok

      Let me put it this way for better understanding.

      saas: You have already built a website/application(Eg: https://www.computenext.com). And you want to host your website/application, you go for this cloud service.

      paas: You are planning to build a website/application(Eg: https://www.computenext.com). And you don’t want to buy Visual studio/Photo shop .. etc softwares on your own. You think if someone would rent you the software license for a week or month. paas will be best option.

      iaas: You want to build a website/application, you want the license of the visual studio/photoshop and you also want to make sure that the system which you work will have certain computational capabilities. iaas comes into picture.

      Hope it makes sense to you.

      • Karan Trivedi

        very well described..thnk you Ashok 🙂

      • Sathasivam Rangasamy


      • SrinivasaRao Bodepudi

        Great! Ashok. Thank you so much for sharing with us. Finally I got it.

      • Rad Kairav

        Hi Ashok,
        I have a different understanding on this.Please correct me if I am wrong.
        saas- you are not going to build your application.You dont want to buy tools and build infrastructure.So,you get managed services from cloud service provider.In this case you dont have to build application,you get application as a service.

        paas-you are going to build your application.you will get tools and infrastructure from cloud service provider.

        iaas – you are going to build your application and also buy tools.but you will just get infrastructure from cloud service provider.

        • Swarup Batabyal

          Yes. You are right.

      • uzma khan

        THIS was best explanation, now get the concept completely. thanks 🙂

        • StrDev

          Actually Ashok’s explanation is wrong. He confuses PaaS and SaaS. The right explanation would be: if a software runs in the cloud (in Ashok’s example Photoshop), than it is SaaS. (Quite straightforward: Software — i.e. Photoshop — as a Cloud.)

          If you want to host your website, than it is not SaaS as Ashok explains, but it is PaaS.

      • vishal kaushik

        I build one app and to host it I took MS Azure subscription. I used the SQL server Database and web server to host my app. As per my understanding, I have consumed iaas ? is it true ?

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  • Adarsh

    would u like to elaborate the expenses in making a seperate cloud for iaas

  • Roberto Barrera

    Smsoma, they Say already, SaaS is Google Apps, PaaS is Google App Engine and for IaaS is like a host service, where you manage your server they only provide it and give you user and password.

  • Avinish Chandra

    I am trying to find out what will be the best for this site(iamwire.com),presently using AWS ec2 cloud service and just want an advice over the pricing issue as to whether it can be cut down using a PaaS service or not(using one small and one big instance on AWS),I am uploading images for better understanding and suggestions.

  • Priyanka

    Salesforce is both SAAS and PAAS,is it true?

    • Ashok

      Force.com is Salesforce.com’s cloud computing platform as a service (PaaS) development framework. It facilitates developers in building multi-tenant applications to be hosted by and presumably integrated to Salesforce.com.

  • mark

  • mark

  • Arvind Modi

    Here is a perfect image explaining these three models of web hosting.
    I believe this will clear the concept.

    Credits to – http://blog.webspecia.com/cloud/iaas-paas-saas-explained-examples-comparison

    • Wonderful explanation dude. I was stuck between these articles. You helped me. Thanks.

      • Hey there this is wonderful, means I got the correct idea what difference they really have .

    • Grey is a Lie

      Beautifully summarized, thanks for sharing

    • mvsagar

      Excellent! I wonder if there can be anything better than this. Thanks for sharing.

    • Rajesh kumar

      Wounderful explanation..Cheers mate…

    • Jin

      Thanks so much Arvind and ComputeNext!

    • Amit Kataria

      Thanks for sharing. Complexity has been explained in a much simplified way. Cheers !!!

  • Arvind Modi

    Here is a perfect image explaining these three models of web hosting.
    I believe this will clear the concept.

    Credits to – http://blog.webspecia.com/cloud/iaas-paas-saas-explained-examples-comparison

  • Mevin_Drake

    IaaS allows an organization to spin up additional resources quickly and efficiently without having to purchase physical hardware, also this model is charged on a “pay-as-you-use” or “pay-as-you-grow” basis charging you for what you are actually using.

  • Ritesh Dwivedi

    Very beautifully explained. Thanks.

  • roopesh sales

    what are the common factors on SaaS,PaaS and IaaS?

    • jamshiyas

      As u can see in Arvind’s post above, physical servers, storage, virtualization and networking are managed by the vendor which is common for all three cloud service models

  • Mike Murphy

    So, does the Saas model mean that the application software always exists on the server or can it be that the software is installed on the client machine and there is a license verification that interacts with the server? Or perhaps the software application lives on the client but some data is exchanged with the server?

    • jamshiyas

      Not really..the software is installed and managed by the vendor. As a client we will use the application (CRM, DMS, etc) using web browsers. At times the software delivery may use some browser plugins, anyway no client software running on user PCs involved.

  • Erin Maccabe

    Thank you for this helpful article regarding the differences between SaaS, IaaS and PaaS (many are still confused as to which is which). Anyway, I think the different needs of a company defines which among the three is the most suitable for them. For me, I think SaaS is the most beneficial one as it handles most of the tasks for the customer (upgrades, back-ups, etc). It also is cost-savvy and rapid to implement. Another thing is that there are SaaS support teams (e.g. Lirik – http://lirik.io/) available to help with matters in regard to SaaS which helps provide maximum SaaS end user experience.

  • Iaas, Paas and Saas these all are the form of cloud computing services. But Iaas services allows the developer to create their own platform and software. And Saas came with the Iaas, but Saas doesn’t offer flexibility of creating custom software as like Iaas. And Paas service provider already built paltform and developer deploy them.

  • Overlapping some of the spectrum of IaaS and PaaS is a new paradigm introduced by Nanobox (http://nanobox.io) called micro-PaaS, which performs many of the functions of PaaS, but is not connected to a particular cloud host (like Heroku with AWS).

    Nanobox’s version of a micro-PaaS includes everything from a local dev environment to automated deployment to a production management console: https://www.youtube.com/watch?v=DbEb8VubvUs

  • Your blog is better but not best because you have to define its usage in real life which is missing from your blog. It is a structure of Cloud which is mostly using in business purpose for hosting Business and Tax applications.
    The SageNext is providing Cloud hosting services for Small and Medium Businesses.

  • Ayaskant Swain

    While i understand IaaS as provisioning of computing hardware such as memory, storage device (ESB or S3 in AWS) , networking , load balancers + the OS (RHEL or SUSE), then what exactly is PaaS? I am not getting a clear answer on this from internet. To me PaaS is the offerings made by cloud providers that help users to develop their application. example – for building a java based web application i will need JRE (Runtime env for my app), Tomcat (to deploy & run my application) & a RDBMS for storing my data (MySql or Oracle). If my cloud provider also provides me all of these softwares will they be called as PaaS?

    Can someone please answer this?

    • Madhusudhan Reddy

      What do you think OpenShift is?

  • Atkia Rose

    for smart home architecture which service above is better ?

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