Salesforce is a cloud-based customer relationship management (CRM) platform and software as a service (SaaS) company that provides services to manage contacts and relationships with customers and potential customers. It also offers a platform as a service (PaaS) allowing customers to build applications that are hosted on Salesforce's infrastructure. The key difference between PaaS and SaaS is that with PaaS, customers can create and host their own applications using tools and libraries from the provider.