Appian Cloud Service

This link helps you to understand more in detail - https://apprenda.com/library/paas/iaas-paas-saas-explained-compared/

For more info: What is the difference between IaaS, SaaS and PaaS?

For the IoT, there are differences between SaaS and PaaS solutions. Perhaps this information will be useful to you: https://www.aimprosoft.com/blog/how-to-develop-iot-app/

read about this - https://computools.com/iot-software-development/

Thanks a lot for help!