Segment
Segment is a customer data platform (CDP) that helps you collect, clean, and control your customer data.

Twilio is an American company based in San Francisco, California providing programmable communication tools for making and receiving phone calls, sending and receiving text messages, and performing other communication functions using its web service APIs. Twilio was founded in 2008 by Jeff Lawson, Evan Cooke, and John Wolthuis and was originally based in both Seattle, Washington, and San Francisco, California.
SendGrid provides a cloud-based service that assists businesses with email delivery. The service manages various types of email including shipping notifications, friend requests, sign-up confirmations, and email newsletters. It also handles internet service provider (ISP) monitoring, domain keys, sender policy framework (SPF), and feedback loops. Additionally, the company provides link tracking, open rate reporting. It also allows companies to track email opens, unsubscribes, bounces, and spam reports.