Mailshake is primarily an email marketing platform that helps businesses automate and personalize their outbound sales communication. It offers features like email sequencing, A/B testing, and analytics to help businesses generate more leads and close more deals. On the other hand, HubSpot CRM is a complete customer relationship management platform that offers a range of marketing, sales, and customer service tools. It helps businesses manage their entire customer journey from lead generation to customer retention. HubSpot CRM includes tools like email marketing, lead tracking, pipeline management, and customer support to enhance customer relationships. Overall, Mailshake focuses on outbound sales communication while HubSpot CRM focuses on managing the end-to-end customer journey.