On-demand software also is known as Software as a Service (SaaS). It is a software distribution model in which services are hosted by a cloud computing service provider. These services are available to end-users over the internet so, the end-users do not need to install any software on their devices to access these services easily. Applications provided by SaaS are listed below:

  • Billing and invoicing system applications
  • Customer Relationship Management (CRM) applications
  • Help desk applications
  • Human Resource (HR) solutions

Software-as–a-Service (SaaS) model allows to provide software application as a service to the end users. It refers to a software that is deployed on a host service and is accessible via Internet. There are several SaaS applications listed below:  Billing and invoicing system Customer Relationship Management (CRM) applications Help desk applications Human Resource (HR) solutions Some of the SaaS applications are not customizable such as Microsoft Office Suite. But SaaS provides us Application Programming Interface (API), which allows the developer to develop a customized application.

All applications provided by SaaD are not customizable such as Microsoft Office Suite  But provide Application Programming Interface (API), which allows the developer to develop a customized application.

Characteristics of the Software as a Service (SaaS)

Some important characteristics of the Software as a Service (SaaS) service model are given below:

  • SaaS provide softare over the Internet.
  • The software applications are maintained by the vendor.
  • The license to the software may be subscription-based or usage-based. And it is billed on a recurring basis.
  • SaaS applications are cost-effective since they do not require any maintenance on the end-user side.
  • SaaS applications are available on demand.
  • We can increase and decrease applications according to need.
  • Automatically upgraded and updated.
  • SaaS offers a shared data model. Therefore, multiple users can share a single instance of infrastructure. It is not required to hardcode the functionality for individual users.
  • All users run the same version of the software at a time.

Advantages of SaaS cloud computing layer

SaaS has proved to be beneficial in terms of efficiency, scalability, and performance. Some Advantages or benefits of SaaS cloud computing are listed below:

  • Easy to buy
  • Modest software tools
  • Multitenant solutions
  • Efficient use of software licenses
  • Centralized management and data
  • Platform responsibilities managed by the provider

Easy to buy

SaaS pricing on based a monthly fee or annual fee subscription, but it is allows organizations to access business functionality at a low cost, which is less than licensed applications. Unlike traditional software, which is sold as a licensed base with an up-front cost (and often optional), SaaS providers are generally pricing the applications using via subscription fee, most commonly a monthly or annual fee.

Multitenant solutions

SaaS services are offered as a one-to-many model means a single instance of the application is shared by multiple users.

Less hardware is required for SaaS

It is less hardware required for software hosted remotely, so organizations do not need to invest in additional hardware. Saas software as a service. it removes the need for installation, set-up, and daily maintenance for the organizations. The initial set-up cost for SaaS is typically less than we can enterprise software. SaaS vendors are pricing their applications based on some usage parameters, such as the number of users using the application.

No special software or hardware versions are required

All users will have a like version of the software and typically access it via the web browser. SaaS reduces IT support costs by outsourcing hardware and software maintenance.

Multidevice support

SaaS services are easily accessed from any device such as desktops, laptops, tablets, phones, and then clients.

API Integration

SaaS services are very easily connected with other software services via standard APIs.

No client-side installation

SaaS services are accessed directly from the service provider and can use the internet connection easily so do not need to require any software and installation.

Issues/Disadvantages of SaaS cloud computing

Some disadvantages or issues associated with SaaS are listed below:

  • Security Issue
  • Latency issue
  • Network dependency
  • Lack of portability between SaaS clouds

Security Issue

Actually, cloud data is stored in the cloud, so security may be an issue for some users. However, cloud computing is not more secure than in-house deployment.

Latency issue

Since data and applications are stored in the cloud at a variable distance from the end-user, there is a possibility that there may be greater latency when interacting with the application compared to local deployment. Therefore, the SaaS model is not suitable for applications whose demand response time is in milliseconds.

Network dependency

Without an internet connection, most SaaS applications are not usable.

Switching between SaaS vendors is difficult

Switching SaaS vendors involves the difficult and slow task of transferring very large data files over the internet and then converting and importing them into another SaaS also.

Open SaaS and SOA

Open SaaS applications are developed by using an open-source programming language. These applications can be run on any open-source operating system and database. Open SaaS application has several benefits over SaaS applications some benefits are listed below:

  • Low Deployment Cost
  • No License Required
  • Less Vendor Lock-in
  • More Robust Solution
  • More portable applications

The following diagram shows the SaaS implementation based on SOA:

Software as a Service | SaaS

Popular SaaS Providers

The below table shows some popular SaaS providers and services that are provided by them -

Provider Services


On-demand CRM solutions

Microsoft Office 365

Online office suite

Google Apps

Gmail, Google Calendar, Docs, and sites


ERP, accounting, order management, CRM, Professionals Services Automation (PSA), and e-commerce applications.


Online meeting and video-conferencing software

Constant Contact

E-mail marketing, online surveys, and event marketing

Oracle CRM

CRM applications

Workday, Inc

Human capital management, payroll, and financial management.