1. IAAS：
基础架构即服务(IAAS)是将计算基础架构作为按需服务交付的方式。它是三个基本的云服务模型服务器存储网络操作系统之一。在用户购买服务器软件数据中心空间或网络设备的过程中，将这些资源出租为完全外包的服务可能需要的模型。它允许动态扩展，并且资源作为服务进行分发。通常在单个硬件上包括多用户。
2. PAAS：
平台即服务(PAAS)是一种云交付模型，用于由第三方管理的服务组成的应用程序。它为您的应用程序提供了弹性扩展，允许开发人员在Internet上构建应用程序和服务，并且部署包括公共，私有和混合。
3. SAAS：
软件即服务(SAAS)允许用户运行现有的在线应用程序，并且它是一种模型软件，已作为托管服务进行部署，并且可以通过输出重述/重新编写的文本访问Internet或软件交付模型，在该模型中，软件及其相关数据处于集中托管，并使用其客户端(通常是网络上的在线浏览器)进行访问。 SAAS服务用于开发和部署现代应用程序。
IAAS，PAAS和SAAS之间的区别：
| Basis Of | IAAS | PAAS | SAAS |
|---|---|---|---|
| Stands for | Infrastructure as a services. | Platform as a services. | Software as a services. |
| Uses | IAAS is used by network architects. | PAAS is used by developer. | SAAS is used by end user. |
| Access | IAAS give access to the resources like virtual machines and virtual storage. | PAAS give access to run time environment to deployment and development tools for application. | SAAS give access to the end user. |
| Model | It is service model that provide visualized computing resources over internet. | It is a cloud computing model that delivers tools that is used for development of application. | It is a service model in cloud computing that host software make available for client. |
| Technical understanding. | It required technical knowledge. | In which you required knowledge of subject to understand basic setup. | There is no requirement about technicalities company handle everything. |
| Popularity. | It is popular between developer and researchers. | It popular between developer who focus on the development of apps and scripts. | It is popular between consumer and company.such as file sharing, email and networking. |
| Cloud services. | Amazon web services, sun, vcloud express. | Facebook, and google search engine. | M.S office web, Facebook and google apps. |
| Enterprise services. | AWS virtual private cloud. | Microsoft azure. | IBM cloud analysis. |
| Outsourced cloud services. | Salesforced. | Force.com, Gigaspaces. | AWS, terremark |