Pipedrive - Sales pipeline software that gets you organized. Helps you focus on the right deals, so easy to use that salespeople just love it. Great for small teams.
Vero - Email platform for product, marketing and engineering teams
Zoho CRM - Omnichannel CRM for Businesses of all sizes
Mailgun - A set of powerful APIs that enable you to send, receive and track email from your app effortlessly whether you use Python, Ruby, PHP, C#, Node.js or Java.
Freshsales CRM - A full-fledged CRM for high-velocity sales teams.
Aritic Mail - Ariticmail is a transactional email delivery API for applications and enterprises.