IaaS, PaaS, and SaaS are the three most popular types of cloud service offerings. They are sometimes referred to as cloud service models or cloud computing service models.

Infrastructure as a service

Also known as IaaS. It is on-demand access to cloud-hosted physical and virtual servers, storage, and networking - the backend IT infrastructure for running applications and workloads in the cloud. The difference is that the cloud service provider hosts, manages, and maintains the hardware and computing resources in its own data centers. IaaS customers use the hardware via an internet connection and pay for that use on a subscription or pay-as-you-go basis. Customers can provision, configure and operate the servers and infrastructure resources via a graphical dashboard, or programmatically through APIs.

IaaS is like a Lego factory.

Benefits

1. Flexibility : Compared to traditional IT, IaaS gives customers more flexibility to build out computing resources as needed and to scale them up or down in response to spikes or slow-downs in traffic.
2. Reduction of customer costs and overhead : It lets customers avoid the up-front expense and overhead of purchasing and maintaining its own on-premises data center.
3. Scalability : It eliminates the constant tradeoff between the waste of purchasing excess on-premises capacity to accommodate spikes, versus the poor performance or outages that can result from not having enough capacity for unanticipated traffic bursts or growth.
4. Higher availability : The company can effortlessly set up backup servers and even deploy them in different locations to guarantee continued operation in case of local power failures or physical disasters.
5. Lower latency, and improved performance : Because IaaS providers typically operate data centers in multiple geographies, IaaS customers can locate apps and services closer to users to minimize latency and maximize performance.
6. Improved responsiveness : Customers can quickly set up resources, try out new ideas rapidly, and easily introduce them to a larger audience.
7. Comprehensive security : With strong security measures in place at the office, data centers, and encryption, organizations can often benefit from enhanced security and protection similar to what they would have if they managed the cloud infrastructure themselves.
8. Faster access to best-of-breed technology : Cloud providers compete by offering cutting-edge technologies to their users. Customers using IaaS can benefit from these technologies much sooner and at a lower cost compared to implementing them in their own physical locations.

Usage

• Disaster recovery
• Ecommerce
• IoT, event processing, AI
• Startups
• Software development

Platform as a service

As known as PaaS. It provides a cloud-based platform for developing, running, and managing applications. The cloud services provider hosts manages and maintains all the hardware and software included in the platform, servers, OS software, storage, networking, databases, middleware, runtimes, frameworks, and development tools. Also provide related services for security, OS and software upgrades, and backups.

Users can access PaaS through GUI. Development or DevOps teams can collaborate on all their work across the entire application lifecycle, coding, integration, testing, delivery, deployment, and feedback.

PaaS is like a Lego brick. PaaS developer provides the Lego bricks to the software developers and the software developers make their own Lego model using the bricks. They do not need to make their own Lego bricks for their service; they just choose the bricks and pay for them.

Benefits

1. Efficiency : Allows customers to build, test, deploy run, update, and scale applications more quickly and cost-effectively than they might if they had to build out and manage their own on-premises platform.
2. Faster time to market : Development teams are able to spin-up development, testing, and production environments in minutes, rather than weeks or months using PaaS.
3. Low- to no-risk testing and adoption of new technologies : Typically, a PaaS platform has an application that includes access to a wide range of up-to-date resources above and below the stack. This enables enterprises to operate new OS without significant investment in systems, languages, and other tools. Users can test the infrastructure required to test or run their system, language, and other tools.
4. Simplified collaboration : As a cloud-based service, PaaS provides a shared software development environment, giving development and operations teams access to all the tools they need, from anywhere with an Internet Connection.
5. A more scalable approach : With PaaS, organizations can purchase extra capacity for building, testing, staging, and running applications whenever they need it.
6. Less to manage : PaaS offloads infrastructure management, patches, updates, and other administrative tasks to the cloud service provider.

Usage

• API development and management
• IoT
• Agile development and DevOps
• Cloud-native development and hybrid cloud strategy

Software as a service

As known as SaaS. It is cloud-hosted, ready-to-use application software. Users pay a monthly or annual fee to use a complete application from within a web browser, desktop client, or mobile app. The application and all of the infrastructure required to deliver it-servers, storage, networking, middleware, application software, data storage-are hosted and managed by the SaaS vendor. Simply, the user does not need to download the software to use.

The vendor manages all upgrades and patches to the software. As part of the Service Level Agreements (SLAs), vendors ensure availability, performance, and security levels. Customers can add more users and data storage on demand by paying extra.

Email, social media, and cloud file storage solutions are examples of SaaS applications. The chatGPT is SaaS product.

SaaS is like already made the Lego model.

Benefits

1. Convenience : SaaS offloads all infrastructure and application management to the SaaS vendor. All the user has to do is create an account, pay the fee, and start using the application. The vendor handles everything else, from maintaining the server hardware and software to managing user access and security, storing and managing data, implementing upgrades and patches, and more.
2. Minimal risk : There is a free trial period or low monthly fees provided by most SaaS providers. Let customers try the software to get used to it or see if it will meet their needs.
3. Anytime/anywhere productivity : If there is an internet connection, the customers can use SaaS products anytime and anywhere. Adding users is as simple as registering and paying for new seats - customers can purchase more data storage for a nominal charge.

Some SaaS vendors allow the user to customize their product from provided a companion PaaS solution.

Reference

What are iaas, paas and SAAS?. IBM. (2024, March 8). https://www.ibm.com/topics/iaas-paas-saas