Outreach.io is a CRM platform for sales teams with features such as email tracking and scheduling, custom templates, analytics, and more. It is designed to help sales teams increase performance and drive more sales. On the other hand, SendGrid is an email delivery platform that allows users to send, track, and deliver emails using APIs and webhooks. It also offers other features such as template libraries, automated email campaigns, and advanced analytics to help businesses create and manage their emails. The key difference between SendGrid and Outreach.io is that SendGrid is focused on email delivery, while Outreach.io focuses on sales automation.