They are cloud-based services to develop software without large investments, since you will only pay for the amount of resources that are used.
Heroku is a very useful example for rapid prototyping, it lets you to configure a scalable server in any language and add any additional services that you might need (e.g logs management, database, cron jobs).
We recommend investigating existing PAAS to develop prototypes, to quickly start testing hypotheses without the need to invest a lot of time and resources.
Platforms as services allow us to test ideas quickly without distracting our I.T. areaPablo Ardiles - Head of CRM Groupon Latam