Ontraport and Constant Contact are two popular marketing automation platforms. The main difference between the two is that Ontraport is geared towards small businesses, while Constant Contact is designed for larger companies. While both platforms feature many of the same marketing functions, such as email marketing, social media management, and contact management, Ontraport provides additional features such as A/B testing, automation, and CRM. Constant Contact also offers additional features such as an event management platform, surveys, and email analytics. Overall, Ontraport is better-suited for small businesses, while Constant Contact is better for larger companies.