PaaS is the provision of access to a platform which allows the customer to deploy software applications without having to buy and maintain the middleware or hardware. It is similar to SaaS but, instead of allowing the customer to simply access and use the software, PaaS allows the customer to access a platform for the creation or management of software applications or services on top of the infrastructure provided by the supplier.
PaaS is defined by NIST as follows:
‘The capability provided to the consumer is to deploy onto the cloud infrastructure consumer-created or acquired applications created using programming languages, libraries, services, and tools supported by the provider. The consumer does not manage or control the underlying cloud infrastructure including network, servers, operating systems, or storage, but has control over the deployed applications and possibly configuration settings for the application-hosting environment.’
PaaS will typically contain not only the elements of IaaS but also such items as:
• application platforms
• integration platforms
• business analytics platforms
• event-streaming services
• monitoring, management, deployment and other related capabilities
Examples of PaaS services include Windows Azure, AWS Elastic Beanstalk, Force.com and Google App Engine.