Outreach.io is an enterprise-level sales engagement platform and automation tool that helps sales teams secure more meetings, and increase pipeline involvement. It uses multi-channel outreach with automated email sequences and activity scoring to prioritize and identify prospective customers. Lemlist, on the other hand, is an automation tool that helps with email outreach. It enables businesses and individual email marketers to design customized email campaigns and automate follow-up emails with personalized content. It has features such as A/B split testing, personalized images, and advanced automation. Outreach.io is better suited for large-scale companies and sales teams, while Lemlist is great for smaller businesses or individual email marketers who are looking for an affordable solution. Outreach.io is more comprehensive and powerful, with advanced features such as an AI-powered lead scoring system, automated workflows, and seamless integrations. Lemlist is less expensive and more user-friendly, but its features cannot match those of Outreach.io.