I've been working with web applications since the 90s, and over the years I've heard many buzzwords which mean "Host your application on system which is run by someone else". The latest buzzword is 'Cloud'.

What is the difference between "Cloud" applications, SaaS (Software as a service) and ASP (Application Service Providers)? Isn't there alot of overlap between these definitions? Sometimes I'm speaking to an executive who keeps saying "Cloud" when I would use the term ASP. I've worked for an organization who did ASP, another who did SaaS, and now another organization who says "Cloud". But they all seem very similar to me.

What distinguishes Cloud vs Saas vs ASP? Are there any official definitions for each of these terms?

5 Answers 5


This blog has a pretty good outline of Saas vs PaaS vs IaaS and compares what Google, Amazon, Azure and other "cloud" providers offer. Here's generally how they breakdown:

Saas vs PaaS vs IaaS

For more information check out this blog post about how Cloud computing compares vs traditional dedicated servers or VPS/VMs. or this post specific for Azure terms and definitions.


As I see it, SaaS is a subset of Cloud. SaaS specifically relates to Software that makes use of the Cloud. There are other Cloud technologies like IaaS (Infrastructure as a Service), PaaS (Platform as a Service, e.g. Force.com, Google App Engine), storage (e.g. Amazon S3) and so on...

As for ASP, I think that's pretty much synonymous with SaaS...


From my understanding all SaaS models essentially utilize the cloud because they are not hosted on the client's server. However, all apps in the Cloud are not necessarily SaaS apps.


ASP and SAAS: application controlled by vendor/provider Cloud Application: application is controlable by tenant

ASP use older technology, could be client/server or traditional webapp SAAS use SOA/WebService/WebApp

ASP and Cloud App: multi-tenancy by multiple instances for each tenant or by os level / app level virtualization SAAS: multi-tenant database design (shared schema, shared database) with addition of tenantid field to differentiate table row owner

SAAS could be a subset of Cloud, but not Cloud App is SAAS (if it not use multi-tenancy but use only virtualization instead)


Cloud Computing is a utility based model. That utility can be hardware (IaaS), software (SaaS), or OS (PaaS) like Azure etc. It's different from ASP as it's hosted else where in any of the cloud providers’ datacenters and you "Pay as you go". Don't have to pay more/less, pay only for what you use. This is SaaS. So ASP is just hosting where as SaaS is metering + billing as you utilize. The resources are provided on demand like VM's, CPU cycles, storage etc.

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