Apollo is mainly a marketing automation platform that focuses on generating more leads, nurturing them, and converting them into customers. It is a cloud-based software that is designed to simplify the marketing process, making it easy to integrate with other marketing tools. On the other hand, Infusionsoft is a robust CRM platform that can automate sales, marketing, and e-commerce activities. It is a comprehensive all-in-one platform that offers features like CRM, marketing automation, e-commerce, and payment processing. Infusionsoft is designed for small to mid-sized businesses who want to grow their customer base and streamline their business processes. Therefore, the key difference between Apollo and Infusionsoft is that Apollo is more focused on marketing automation, while Infusionsoft is a combination of CRM, e-commerce, and marketing automation.